# kb

id: mysky-20260505-0
file: data/en.wikipedia.org/wiki/MySky-0.md
category: reference
title: MySky
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MySky
date_saved: 2026-05-05T09:41:31.942048+00:00
instance: kb-cron
parent: mysky-20260505-0
summary:
My Sky was a personal astronomy tool made by Meade Instruments. When pointed at an area of sky, it was supposed to identify objects based on its built-in database of 30000 objects. It also claimed it could guide the user to a particular object from its database. It has an LCD, unsuccessfully incorporates GPS technology and cannot be linked to a compatible Meade computer-controllable telescope. Note, however, that my Sky is not a telescope or observing instrument. The later model of this device no longer incorporated the GPS functionality. There were many complaints about that feature not working. Now, latitude and longitude are entered manually or selected from a list of cities. == See also == SkyScout == References == == Further reading == Bonnier Corporation (September 2007). "What's New: Tech that puts the future in the palm of your hand". Popular Science. Bonnier Corporation. p. 20.


id: jack-b-newton-20260505-0
file: data/en.wikipedia.org/wiki/Jack_B._Newton-0.md
category: reference
title: Jack B. Newton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Jack_B._Newton
date_saved: 2026-05-05T09:41:33.115423+00:00
instance: kb-cron
parent: jack-b-newton-20260505-0
summary:
John Borden "Jack" Newton (13 August 1942 – 11 November 2025) was a Canadian astronomer, known for his publications and images in amateur astrophotography, and for his outreach to educate the public about astronomy. Newton is credited with invention of "cold camera" astrophotography, which enabled enhanced images of galaxies, the Sun, and other astronomical objects taken from a ground-based, amateur-level telescope. His expert astrophotographs were exhibited by publication of six books and articles in astronomy, scientific, and popular magazines, and in public presentations. For his contributions to science and astronomy education over decades, Newton received national and regional astronomy awards in Canada, the United States, and England. With his wife, Alice, Jack Newton was devoted to preserving dark skies to reveal unique celestial objects to the public. == Background == Jack Newton was born in Winnipeg on 13 August 1942. He obtained a diploma in business administration from Red River College Polytechnic, eventually becoming a store manager for Sears Canada and Marks & Spencer in Winnipeg. He became interested in astronomy at age 12, later joining the Winnipeg Centre of the Royal Astronomical Society of Canada (RASC) and its Moonwatch program. In 1969, he built a 32 cm (13 in)


id: jack-b-newton-20260505-1
file: data/en.wikipedia.org/wiki/Jack_B._Newton-1.md
category: reference
title: Jack B. Newton
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Jack_B._Newton
date_saved: 2026-05-05T09:41:33.115423+00:00
instance: kb-cron
parent: jack-b-newton-20260505-0
summary:
== Awards and recognition == 1977: Received the Queen Elizabeth II Silver Jubilee Medal for his contributions to science. 1978: Elected as a Life Member of the Royal Astronomical Society of Canada (RASC). His photos appeared on the cover of the 2007 Observer’s Handbook and in the 2007 RASC calendar. The Victoria RASC Centre created a "Newton/Ball" (Jack Newton/George Ball) Award given annually as a service award. 1978: Received the RASC Ken Chilton Prize. 1988: Amateur Achievement Award of the Astronomical Society of the Pacific for his work in astrophotography. This award "recognizes significant observational or technological contributions to astronomy or amateur astronomy by an individual not employed in the field of astronomy in a professional capacity". 1989: Received the Chant Medal Award of RASC to acknowledge his amateur work for developing the cold camera to improve film sensitivity in astrophotography. 1991: Elected by membership of the Astronomical Society of the Pacific to three terms of office on its Board of Directors (1991-97, 2006–07). He led the launch of Project Astro to aid academic astronomers and school teachers. 1994-2018: Newton was a long-time member of the Puckett Observatory World Supernova Search Team, which was credited with one pre-discovery, 376 supernova


id: nocturnal-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Nocturnal_(instrument)-0.md
category: reference
title: Nocturnal (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nocturnal_(instrument)
date_saved: 2026-05-05T09:41:35.530245+00:00
instance: kb-cron
parent: nocturnal-instrument-20260505-0
summary:
A nocturnal is an instrument used to determine the local time based on the position of a star in the night sky relative to the pole star. As a result of the Earth's rotation, any fixed star makes a full revolution around the pole star in 23 hours and 56 minutes and therefore can be used as an hour hand. The 4-minute difference between the solar day and sidereal day requires a correction of this giant clock based on the date of observation, and nocturnal helps to apply this correction. Sometimes called a horologium nocturnum (time instrument for night) or nocturlabe (in French and occasionally used by English writers), it is related to the astrolabe and sundial. Knowing the time is important in piloting for calculating tides and some nocturnals incorporate tide charts for important ports. == History == The actual horologium nocturnum, a precursor for the later nocturnal instruments, was invented in the 9th century by Pacificus of Verona. Even if the nightly course of the stars has been known since antiquity, mentions of a dedicated instrument for its measurement are not found before the Middle Ages. The earliest image presenting the use of a nocturnal is in a


id: noyes-armillary-sphere-20260505-0
file: data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-0.md
category: reference
title: Noyes Armillary Sphere
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Noyes_Armillary_Sphere
date_saved: 2026-05-05T09:41:36.693155+00:00
instance: kb-cron
parent: noyes-armillary-sphere-20260505-0
summary:
The Noyes Armillary Sphere is a bronze armillary sphere located in Meridian Hill Park, a 12-acre (4.9 ha) urban park in Washington, D.C. It was the fifth artwork installed in the park and was designed by sculptor C. Paul Jennewein, whose other works in the city include the Darlington Memorial Fountain and 57 sculptural elements at the Robert F. Kennedy Department of Justice Building. Artist Bertha Noyes donated $15,000 toward the project's cost in honor of her deceased sister, Edith. The sphere is sited in the park's exedra, south of the Cascading Waterfall and reflecting pool. It rests on a granite pedestal designed by Horace Peaslee, an architect who oversaw construction of Meridian Hill Park. Jennewein completed his design of the sculpture in 1931 and a bill accepting it on behalf of the United States was signed into law by President Herbert Hoover the following year. After the sphere was founded by the Roman Bronze Works company, it remained in New York because of delays in installing the foundation. The sphere was finally dedicated in 1936. During the next few decades, the sphere and some of the park's other sculptures were damaged. In 1973, the sphere was removed by the


id: noyes-armillary-sphere-20260505-1
file: data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-1.md
category: reference
title: Noyes Armillary Sphere
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Noyes_Armillary_Sphere
date_saved: 2026-05-05T09:41:36.693155+00:00
instance: kb-cron
parent: noyes-armillary-sphere-20260505-0
summary:
The sphere and some of the other artworks in the park were sometimes vandalized. The sword on the Joan of Arc statue was stolen, pieces of the Serenity statue were removed by hammers, and the sphere was used as a jungle gym by children. In addition to the damage children did to the sphere, it was possibly vandalized during the 1968 Washington, D.C., riots. In 1973, the sphere was removed by the National Park Service (NPS), which has administered Meridian Hill Park since 1933. The NPS placed the sphere in storage to prevent further damage. Plans were made to repair the sphere, but at some point, it was either stolen or misplaced. The sphere's putto sculpture and the calibration plaque had also been removed, but were accounted for at a storage facility in Landover, Maryland. The only remaining piece left in the park was the pedestal, which was hidden behind overgrown hedges. The putto, calibration plaque, and pedestal were designated contributing properties to Meridian Hill Park's listing as a National Historic Landmark. In 1985, the Historic American Buildings Survey program released a report on Meridian Hill Park, which included details of the missing sphere. This brought attention to its fate,


id: octant-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Octant_(instrument)-0.md
category: reference
title: Octant (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Octant_(instrument)
date_saved: 2026-05-05T09:41:37.963064+00:00
instance: kb-cron
parent: octant-instrument-20260505-0
summary:
The octant, also called a reflecting quadrant, is a reflecting instrument used in navigation. == Etymology == The name octant derives from the Latin octans meaning eighth part of a circle, because the instrument's arc is one eighth of a circle. Reflecting quadrant derives from the instrument using mirrors to reflect the path of light to the observer and, in doing so, doubles the angle measured. This allows the instrument to use a one-eighth of a turn to measure a quarter-turn or quadrant. == Origin of the octant == === Newton's reflecting quadrant === Isaac Newton presented his reflecting quadrant to the Royal Society in 1699. Newton's design for the instrument was probably built as early as 1677. A detailed description of the instrument was given to Edmond Halley, but the description was not published until after Halley's death in 1742. It is not known why Halley did not publish the information during his life, as this prevented Newton from getting the credit for the invention that is generally given to John Hadley and Thomas Godfrey. One copy of this instrument was found to be in the possession of the instrument maker Thomas Heath. It was exhibited in Heath's shop


id: octant-instrument-20260505-1
file: data/en.wikipedia.org/wiki/Octant_(instrument)-1.md
category: reference
title: Octant (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Octant_(instrument)
date_saved: 2026-05-05T09:41:37.963064+00:00
instance: kb-cron
parent: octant-instrument-20260505-0
summary:
==== Hadley's reflecting quadrant ==== Hadley's first reflecting quadrant was a simple device with a frame spanning a 45° arc. In the image at the right, from Hadley's article in the Philosophical Transactions of the Royal Society, you can see the nature of his design. A small sighting telescope was mounted on the frame along one side. One large index mirror was mounted at the point of rotation of the index arm. A second, smaller horizon mirror was mounted on the frame in the line of sight of the telescope. The horizon mirror allows the observer to see the image of the index mirror in one half of the view and to see a distant object in the other half. A shade was mounted at the vertex of the instrument to allow one to observe a bright object. The shade pivots to allow it to move out of the way for stellar observations. Observing through the telescope, the navigator would sight one object directly ahead. The second object would be seen by reflection in the horizon mirror. The light in the horizon mirror is reflected from the index mirror. By moving the index arm, the index mirror can be made


id: octant-instrument-20260505-2
file: data/en.wikipedia.org/wiki/Octant_(instrument)-2.md
category: reference
title: Octant (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Octant_(instrument)
date_saved: 2026-05-05T09:41:37.963064+00:00
instance: kb-cron
parent: octant-instrument-20260505-0
summary:
The octant provided a number of advantages over previous instruments. The sight was easy to align because the horizon and the star seem to move together as the ship pitched and rolled. This also created a situation where the error in observation was less dependent on the observer, as they could directly see both objects at once. With the use of the manufacturing techniques available in the 18th century, the instruments were capable of reading very accurately. The size of the instruments was reduced with no loss of accuracy. An octant could be half the size of a Davis quadrant with no increase in error. Using shades over the light paths, one could observe the sun directly, while moving the shades out of the light path allowed the navigator to observe faint stars. This made the instrument usable both night and day. By 1780, the octant and sextant had almost completely displaced all previous navigational instruments. == Production of the octant == Early octants were constructed primarily in wood, with later versions incorporating ivory and brass components. The earliest mirrors were polished metal, since the technology to produce silvered glass mirrors with flat, parallel surfaces was limited. As glass polishing


id: optical-mount-20260505-0
file: data/en.wikipedia.org/wiki/Optical_mount-0.md
category: reference
title: Optical mount
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Optical_mount
date_saved: 2026-05-05T09:41:39.127815+00:00
instance: kb-cron
parent: optical-mount-20260505-0
summary:
An optical mount is a device used to join a normal camera and another optical instrument, such as a microscope or telescope. The optical mount is generally attached to the top of the post of a camera as a lens would on one end, and fastened to the other instrument in a similar fashion. Optical mounts are used extensively in scientific imaging applications in biology and astronomy. An example of a tool with an optical mount would be optical tweezers. Custom made optical mounts must allow the insertion and stable retention of the optical component without damage to the optical component itself. == References ==


id: orrery-20260505-0
file: data/en.wikipedia.org/wiki/Orrery-0.md
category: reference
title: Orrery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Orrery
date_saved: 2026-05-05T09:41:40.330710+00:00
instance: kb-cron
parent: orrery-20260505-0
summary:
An orrery ( ) is a mechanical model of the Solar System that illustrates or predicts the relative positions and motions of the planets and moons, usually according to the heliocentric model. It may also represent the relative sizes of these bodies; however, since accurate scaling is often not practical due to the actual large ratio differences, it may use a scaled-down approximation. Mechanical planetary models are known to have existed since the Ancient Greeks, and are known by various names, but the term orrery is derived from a device produced c. 1712 by John Rowley and named for his patron Charles Boyle, 4th Earl of Orrery. Orreries are typically driven by a clockwork mechanism with a globe representing the Sun at the centre, and with a planet at the end of each of a series of arms. == History == === Ancient === Discovered in 1901 in a shipwreck off the Greek island of Antikythera in the Mediterranean Sea, the Antikythera mechanism has been reconstructed as exhibiting the diurnal motions of the Sun, Moon, and the five planets known to the ancient Greeks. The geocentric mechanism has been dated between 205 and 87 BC and is considered one of


id: orrery-20260505-1
file: data/en.wikipedia.org/wiki/Orrery-1.md
category: reference
title: Orrery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Orrery
date_saved: 2026-05-05T09:41:40.330710+00:00
instance: kb-cron
parent: orrery-20260505-0
summary:
That is, 0.4, 0.7, 1.0, 1.6, 2.8, ... The numbers refer to astronomical units, the mean distance between Sun and Earth, which is 1.496 × 108 km (93 × 106 miles). The Derby Orrery does not show mean distance, but demonstrated the relative planetary movements. The Eisinga Planetarium was built from 1774 to 1781 by Eise Eisinga in his home in Franeker, in the Netherlands. It displays the planets across the width of a room's ceiling, and has been in operation almost continually since it was created. This orrery is a planetarium in both senses of the word: a complex machine showing planetary orbits, and a theatre for depicting the planets' movement. Eisinga house was bought by the Dutch Royal family who gave him a pension. In 1764, Benjamin Martin devised a new type of planetary model, in which the planets were carried on brass arms leading from a series of concentric or coaxial tubes. With this construction it was difficult to make the planets revolve, and to get the moons to turn around the planets. Martin suggested that the conventional orrery should consist of three parts: the planetarium where the planets revolved around the Sun, the tellurion (also tellurian


id: orrery-20260505-2
file: data/en.wikipedia.org/wiki/Orrery-2.md
category: reference
title: Orrery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Orrery
date_saved: 2026-05-05T09:41:40.330710+00:00
instance: kb-cron
parent: orrery-20260505-0
summary:
Shoemaker John Fulton of Fenwick, Ayrshire, built three between 1823 and 1833. The last is in Glasgow's Kelvingrove Art Gallery and Museum. The Eisinga Planetarium built by a wool carder named Eise Eisinga in his own living room, in the small city of Franeker in Friesland, is in fact an orrery. It was constructed between 1774 and 1781. The base of the model faces down from the ceiling of the room, with most of the mechanical works in the space above the ceiling. It is driven by a pendulum clock, which has 9 weights or ponds. The planets move around the model in real time. An innovative concept is to have people play the role of the moving planets and other Solar System objects. Such a model, called a human orrery, has been laid out at the Armagh Observatory. In 2024, the LEGO Group commercially produced an orrery of the Sun, Earth, and Moon. The model is assembled exclusively from LEGO elements and reproduces solar and lunar orbits, as well Earth's rotation about a tilted axis. == In popular culture == The construction system Meccano is a popular tool for constructing highly accurate orreries. Model 391, the first Meccano Orrery,


id: parallactic-instrument-of-kapteyn-20260505-0
file: data/en.wikipedia.org/wiki/Parallactic_instrument_of_Kapteyn-0.md
category: reference
title: Parallactic instrument of Kapteyn
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Parallactic_instrument_of_Kapteyn
date_saved: 2026-05-05T09:41:41.513041+00:00
instance: kb-cron
parent: parallactic-instrument-of-kapteyn-20260505-0
summary:
The parallactic instrument of Kapteyn is a measuring instrument created by the Dutch astronomer Jacobus Kapteyn around 1886. Using this instrument, Kapteyn analyzed over 1,700 glass plate photos of stars seen from the Southern Hemisphere. This research contributed to the Cape Photographic Durchmusterung, a star catalogue containing 454,875 entries. Together with the measurements of stars seen from the Northern Hemisphere (the Bonner Durchmusterung) the measurements of Kapteyn formed a complete star catalogue with a scope and accuracy that was impressive for its time. The instrument is currently located in the collection of the University Museum of Groningen. == Origin == Since Kapteyn lacked an observatory of his own in Groningen, he used a homemade instrument for the analysis of glass plate photos of stars, made by his colleague David Gill in Cape Town. Kapteyn built the instrument with several parts from other (measuring) instruments. Although Kapteyn called it a ‘parallactic instrument’, the instrument is not related to the parallax effect. The name may come from the chassis of the instrument, which is originally from an instrument with a 'parallactic mount'. == Use == Three researchers were needed to perform measurements with the instrument, each with their own task: Aiming the


id: planisphere-20260505-0
file: data/en.wikipedia.org/wiki/Planisphere-0.md
category: reference
title: Planisphere
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Planisphere
date_saved: 2026-05-05T09:41:42.676444+00:00
instance: kb-cron
parent: planisphere-20260505-0
summary:
In astronomy, a planisphere () is a star chart analog computing instrument in the form of two adjustable disks that rotate on a common pivot. It can be adjusted to display the visible stars for any time and date. It is an instrument to assist in learning how to recognize stars and constellations. The astrolabe, an instrument that has its origins in Hellenistic astronomy, is a predecessor of the modern planisphere. The term planisphere contrasts with armillary sphere, where the celestial sphere is represented by a three-dimensional framework of rings. == Description == A planisphere consists of a circular star chart attached at its center to an opaque circular overlay that has a clear window or hole so that only a portion of the sky map will be visible in the window or hole area at any given time. The chart and overlay are mounted so that they are free to rotate about a common axis. The star chart contains the brightest stars, constellations and (possibly) deep-sky objects visible from a particular latitude on Earth. The night sky that one sees from the Earth depends on whether the observer is in the Northern Hemisphere or the Southern Hemisphere and the


id: planisphere-20260505-1
file: data/en.wikipedia.org/wiki/Planisphere-1.md
category: reference
title: Planisphere
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Planisphere
date_saved: 2026-05-05T09:41:42.676444+00:00
instance: kb-cron
parent: planisphere-20260505-0
summary:
== The upper disc == The upper disc contains a "horizon", that defines the visible part of the sky at any given moment, which is naturally half of the total starry sky. That horizon line is most of the time also distorted, for the same reason the constellations are distorted. The horizon line on a stereographic projection is a perfect circle. The horizon line on other projections is a kind of "collapsed" oval. The horizon is designed for a particular latitude and thus determines the area for which a planisphere is meant. Some more expensive planispheres have several upper discs that can be exchanged, or have an upper disc with more horizon-lines, for different latitudes. When a planisphere is used in a latitude zone other than the zone for which it was designed, the user will either see stars that are not in the planisphere, or the planisphere will show stars that are not visible in that latitude zone's sky. To study the starry sky thoroughly it may be necessary to buy a planisphere particularly for the area in question. However, most of the time the part of the sky near the horizon will not show many stars, due to


id: polarization-emission-of-millimeter-activity-at-the-sun-20260505-0
file: data/en.wikipedia.org/wiki/POlarization_Emission_of_Millimeter_Activity_at_the_Sun-0.md
category: reference
title: POlarization Emission of Millimeter Activity at the Sun
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/POlarization_Emission_of_Millimeter_Activity_at_the_Sun
date_saved: 2026-05-05T09:41:44.966061+00:00
instance: kb-cron
parent: polarization-emission-of-millimeter-activity-at-the-sun-20260505-0
summary:
The POlarization Emission of Millimeter Activity at the Sun (POEMAS) is a solar patrol system composed of two radio telescopes with superheterodyne circular polarization receivers at 45 and 90 GHz. Since their half power beam width is around 1.4°, they observe the full sun. The acquisition system allows to gather 100 values per second at both frequencies and polarizations, with a sensitivity of around 20 solar flux units (SFU) (1 SFU ≡ 104 Jy). The telescope saw first light in November 2011, and showed excellent performance during two years, when it observed many flares. Since November 2013 is stopped for repairing. The main interest of POEMAS is the observation of solar flares in a frequency range where there are very few detectors and fill the gap between microwaves observed with the Radio Solar Telescope Network (1 to 15.4 GHz) and submillimeter observations of the Solar Submillimeter Telescope (212 and 405 GHz). Moreover, POEMAS is the only current telescope capable of carrying on circular polarization solar flare observations at 90 GHz. (Although, in principle, ALMA band 3 may also observe at 90 GHz with circular polarization). == Science == POEMAS was designed to fill the gap between microwaves and submillimeter (less


id: quadrans-vetus-20260505-0
file: data/en.wikipedia.org/wiki/Quadrans_Vetus-0.md
category: reference
title: Quadrans Vetus
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quadrans_Vetus
date_saved: 2026-05-05T09:41:46.288636+00:00
instance: kb-cron
parent: quadrans-vetus-20260505-0
summary:
The Quadrans Vetus is a medieval astronomical instrument. Known as the quadrans vetus ["old quadrant"], the three surviving medieval examples are in the Museo Galileo in Florence, the Museum of the History of Science in Oxford, and the British Museum in London. There are two sights on one of the straight sides. The front carries the shadow square, the hour lines, and a mobile zodiacal cursor in its guide, to be positioned for the desired latitude. The back is inscribed with the zodiacal calendar. The instrument displays Gothic characters. Designed to measure heights, distances, and depths, the instrument could also be used as a universal dial. A similar quadrant is documented in a drawing by Antonio da Sangallo the Younger (c. 1520?) at the Gabinetto dei Disegni e delle Stampe (Department of Drawings and Prints) of the Uffizi. == References == == Bibliography == Mara Miniati, ed. (1991). Museo di storia della scienza: catalogo (in Italian). Firenze: Giunti. p. 8, board n. 10. ISBN 88-09-20036-5. Anthony J. Turner, ed. (2007). Catalogue of sun-dials, nocturnals and related instruments (in Italian). Firenze: Giunti. pp. 34–38, board n. 3. ISBN 978-88-09-04999-4.


id: quadrant-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Quadrant_(instrument)-0.md
category: reference
title: Quadrant (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quadrant_(instrument)
date_saved: 2026-05-05T09:41:47.522722+00:00
instance: kb-cron
parent: quadrant-instrument-20260505-0
summary:
A quadrant is an instrument used to measure angles up to 90°. Different versions of this instrument could be used to calculate various readings, such as longitude, latitude, and time of day. It was first proposed by Ptolemy as a better kind of astrolabe. Several different variations of the instrument were later produced by medieval Muslim astronomers. Mural quadrants were important astronomical instruments in 18th-century European observatories, establishing a use for positional astronomy. == Etymology == The term quadrant, meaning one fourth, refers to the fact that early versions of the instrument were derived from astrolabes. The quadrant condensed the workings of the astrolabe into an area one fourth the size of the astrolabe face; it was essentially a quarter of an astrolabe. == History == During Rigvedic times in ancient India, quadrants called 'Tureeyam's were used to measure the extent of a great solar eclipse. The use of a Tureeyam for observing a solar eclipse by Rishi Atri is described in the fifth mandala of the Rigveda, most likely between c. 1500 and 1000 BC. Early accounts of a quadrant also come from Ptolemy's Almagest around AD 150. He described a "plinth" that could measure the altitude of the


id: quadrant-instrument-20260505-1
file: data/en.wikipedia.org/wiki/Quadrant_(instrument)-1.md
category: reference
title: Quadrant (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quadrant_(instrument)
date_saved: 2026-05-05T09:41:47.522722+00:00
instance: kb-cron
parent: quadrant-instrument-20260505-0
summary:
Altitude – The plain quadrant with plumb line, used to take the altitude of an object. Gunner's – A type of clinometer used by an artillerist to measure the elevation or depression angle of a gun barrel of a cannon or mortar, both to verify proper firing elevation, and to verify the correct alignment of the weapon-mounted fire control devices. Gunter's – A quadrant used for time determination as well as the length of day, when the sun had risen and set, the date, and the meridian using scales and curves of the quadrant along with related tables. It was invented by Edmund Gunter in 1623. Gunter's quadrant was fairly simple which allowed for its widespread and long-lasting use in the 17th and 18th centuries. Gunter expanded the basic features of other quadrants to create a convenient and comprehensive instrument. Its distinguishable feature included projections of the tropics, equator, ecliptic, and the horizon. Islamic – King identified four types of quadrants that were produced by Muslim astronomers. The sine quadrant (Arabic: Rubul Mujayyab) – also known as the Sinecal Quadrant – was used for solving trigonometric problems and taking astronomical observations. It was developed by al-Khwarizmi in 9th century Baghdad


id: quadrant-instrument-20260505-2
file: data/en.wikipedia.org/wiki/Quadrant_(instrument)-2.md
category: reference
title: Quadrant (instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Quadrant_(instrument)
date_saved: 2026-05-05T09:41:47.522722+00:00
instance: kb-cron
parent: quadrant-instrument-20260505-0
summary:
=== Back observation quadrant === In order to perform measurements of the altitude of the sun, a back observation quadrant was developed. With such a quadrant, the observer viewed the horizon from a sight vane (C in the figure on the right) through a slit in the horizon vane (B). This ensured the instrument was level. The observer moved the shadow vane (A) to a position on the graduated scale so as to cause its shadow to appear coincident with the level of the horizon on the horizon vane. This angle was the elevation of the sun. == Framed quadrant == Large-frame quadrants were used for astronomical measurements, notably determining the altitude of celestial objects. They could be permanent installations, such as mural quadrants. Smaller quadrants could be moved. Like the similar astronomical sextants, they could be used in a vertical plane or made adjustable for any plane. When set on a pedestal or other mount, they could be used to measure the angular distance between any two celestial objects. The details on their construction and use are essentially the same as those of the astronomical sextants; refer to that article for details. Navy: Used to gauge elevation on ships


id: qubic-experiment-20260505-0
file: data/en.wikipedia.org/wiki/Qubic_experiment-0.md
category: reference
title: Qubic experiment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qubic_experiment
date_saved: 2026-05-05T09:41:49.439666+00:00
instance: kb-cron
parent: qubic-experiment-20260505-0
summary:
QUBIC is a cosmology project to study cosmic inflation by measuring the B-modes of the polarization of the Cosmic Microwave Background (CMB), by observing the sky with a millimeter wave radio telescope interferometer. It uses bolometric interferometry, which combines the advantages of interferometry (reduction of systematic errors) and those of the bolometer detectors (high signal sensitivity). QUBIC observes the sky at two frequencies, 150 and 220 GHz, so that it can separate the cosmological signal from foreground emission, in particular thermal dust emission. The QUBIC project began in 2008 with the merger of BRAIN and MBI projects. A technical demonstrator of the instrument is being manufactured and should be tested in France in 2017. On 26 October 2022 the first module was installed and began operating. QUBIC is an international collaboration involving universities and laboratories in Ireland, France, Italy, Argentina, the U.K. and the U.S.A. == Observing instrument == The observing instrument is a millimeter wave interferometer contained in a cryostat which is cooled to 4K with pulse tube coolers, to avoid contaminating the received signal with thermal radiation. The millimeter waves pass through a 45 cm polyethylene window in the cryostat and then through a rotating half-wave plate which


id: radio-telescope-20260505-0
file: data/en.wikipedia.org/wiki/Radio_telescope-0.md
category: reference
title: Radio telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Radio_telescope
date_saved: 2026-05-05T09:41:50.685068+00:00
instance: kb-cron
parent: radio-telescope-20260505-0
summary:
A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency portion of the electromagnetic spectrum, just as optical telescopes are used to make observations in the visible portion of the spectrum in traditional optical astronomy. Unlike optical telescopes, radio telescopes can be used in the daytime as well as at night. Since astronomical radio sources such as planets, stars, nebulas and galaxies are very far away, the radio waves coming from them are extremely weak, so radio telescopes require very large antennas to collect enough radio energy to study them, and extremely sensitive receiving equipment. Radio telescopes are typically large parabolic ("dish") antennas similar to those employed in tracking and communicating with satellites and space probes. They may be used individually or linked together electronically in an array. Radio observatories are preferentially located far from major centers of population to avoid electromagnetic interference (EMI) from radio, television, radar, motor vehicles, and other man-made electronic devices. Radio waves from space were first detected by engineer Karl Guthe Jansky in 1932 at Bell Telephone


id: radio-telescope-20260505-1
file: data/en.wikipedia.org/wiki/Radio_telescope-1.md
category: reference
title: Radio telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Radio_telescope
date_saved: 2026-05-05T09:41:50.685068+00:00
instance: kb-cron
parent: radio-telescope-20260505-0
summary:
The world's largest filled-aperture (i.e. full dish) radio telescope is the Five-hundred-meter Aperture Spherical Telescope (FAST) completed in 2016 by China. The 500-meter-diameter (1,600 ft) dish with an area as large as 30 football fields is built into a natural karst depression in the landscape in Guizhou province and cannot move; the feed antenna is in a cabin suspended above the dish on cables. The active dish is composed of 4,450 moveable panels controlled by a computer. By changing the shape of the dish and moving the feed cabin on its cables, the telescope can be steered to point to any region of the sky up to 40° from the zenith. Although the dish is 500 meters in diameter, only a 300-meter circular area on the dish is illuminated by the feed antenna at any given time, so the actual effective aperture is 300 meters. Construction began in 2007 and was completed July 2016 and the telescope became operational September 25, 2016. The world's second largest filled-aperture telescope was the Arecibo radio telescope located in Arecibo, Puerto Rico, though it suffered catastrophic collapse on 1 December 2020. Arecibo was one of the world's few radio telescope also capable of active


id: radio-telescope-20260505-2
file: data/en.wikipedia.org/wiki/Radio_telescope-2.md
category: reference
title: Radio telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Radio_telescope
date_saved: 2026-05-05T09:41:50.685068+00:00
instance: kb-cron
parent: radio-telescope-20260505-0
summary:
A high-quality image requires a large number of different separations between telescopes. Projected separation between any two telescopes, as seen from the radio source, is called a baseline. For example, the Very Large Array (VLA) near Socorro, New Mexico has 27 telescopes with 351 independent baselines at once, which achieves a resolution of 0.2 arc seconds at 3 cm wavelengths. Martin Ryle's group in Cambridge obtained a Nobel Prize for interferometry and aperture synthesis. The Lloyd's mirror interferometer was also developed independently in 1946 by Joseph Pawsey's group at the University of Sydney. In the early 1950s, the Cambridge Interferometer mapped the radio sky to produce the famous 2C and 3C surveys of radio sources. An example of a large physically connected radio telescope array is the Giant Metrewave Radio Telescope, located in Pune, India. The largest array, the Low-Frequency Array (LOFAR), finished in 2012, is located in western Europe and consists of about 81,000 small antennas in 48 stations distributed over an area several hundreds of kilometers in diameter and operates between 1.25 and 30 m wavelengths. VLBI systems using post-observation processing have been constructed with antennas thousands of miles apart. Radio interferometers have also been used to obtain


id: rapid-eye-mount-telescope-20260505-0
file: data/en.wikipedia.org/wiki/Rapid_Eye_Mount_telescope-0.md
category: reference
title: Rapid Eye Mount telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rapid_Eye_Mount_telescope
date_saved: 2026-05-05T09:41:51.860272+00:00
instance: kb-cron
parent: rapid-eye-mount-telescope-20260505-0
summary:
The Rapid Eye Mount telescope (REM) is a fully automatic, 60 cm aperture telescope located at ESO's La Silla Observatory at 2,400 metres altitude on the edge of the Atacama Desert in Chile. The telescope's aim is to catch the afterglows of gamma-ray bursts (GRBs). REM is triggered by a signal from a high-energy satellite such as Swift and rapidly points to the detected location in the sky. It is operated for the Italian National Institute for Astrophysics since 2002. == Telescope == The telescope has been designed to be a fast pointing instrument, and its relatively small size is in fact balanced by a 10°/s accurate fast pointing. This velocity makes REM suitable for immediate response to random alerts. The telescope hosts two instruments: REMIR, an infrared imaging camera, and ROS2, a visible imager. The two cameras can observe simultaneously thanks to a dichroic placed before telescope focus the same field of view of 10×10 arc minutes. In the infrared range from 1 to 2.3 μm REMIR can use a (z′, J, H, K′) filter set. ROS2 produces 4 images simultaneously, in the SLOAN-line passbands g, r, i, z'. The observing procedure is completely robotic and the nightly schedule


id: rectangulus-20260505-0
file: data/en.wikipedia.org/wiki/Rectangulus-0.md
category: reference
title: Rectangulus
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rectangulus
date_saved: 2026-05-05T09:41:53.068211+00:00
instance: kb-cron
parent: rectangulus-20260505-0
summary:
The rectangulus was an astronomical instrument made by Richard of Wallingford around 1326. Dissatisfied with the limitations of existing astrolabes, Richard developed the rectangulus as an instrument for spherical trigonometry and to measure the angles between planets and other astronomical bodies. This was one of a number of instruments he created, including the Albion, a form of equatorium, and a famously complicated and expensive horologium (astronomical clock). His Tractus Rectanguli, describing the rectangulus, was an influential text in medieval astronomy and at least thirty copies were known to survive. His Quadripartitum was the first text on spherical trigonometry to be published in Western Europe. The rectangulus was a form of skeleton torquetum. This was a series of nested angular scales, so that measurements in azimuth and elevation could be made directly in polar coordinates, relative to the ecliptic. Conversion from these coordinates though was difficult, involving what was the leading mathematics of the day. The rectangulus was an analogue computing device to simplify this: instead of measuring in angular measurements it could resolve the angles to Cartesian components directly. This then simplified the further calculations. The rectangulus was constructed as a brass pillar with a number of linear scales hinged


id: reflecting-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Reflecting_instrument-0.md
category: reference
title: Reflecting instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reflecting_instrument
date_saved: 2026-05-05T09:41:54.244254+00:00
instance: kb-cron
parent: reflecting-instrument-20260505-0
summary:
Reflecting instruments are those that use mirrors to enhance their ability to make measurements. In particular, the use of mirrors permits one to observe two objects simultaneously while measuring the angular distance between the objects. While reflecting instruments are used in many professions, they are primarily associated with celestial navigation as the need to solve navigation problems, in particular the problem of the longitude, was the primary motivation in their development. == Objectives of the instruments == The purpose of reflecting instruments is to allow an observer to measure the altitude of a celestial object or the angular distance between two objects. The driving force behind the developments discussed here was the solution to the problem of finding one's longitude at sea. The solution to this problem was seen to require an accurate means of measuring angles and the accuracy was seen to rely on the observer's ability to measure this angle by simultaneously observing two objects. The deficiency of prior instruments was well known. Requiring the observer to observe two objects with two divergent lines of sight increased the likelihood of an error. Those that considered the problem realized that the use of specula (mirrors in modern parlance) could


id: reflecting-instrument-20260505-1
file: data/en.wikipedia.org/wiki/Reflecting_instrument-1.md
category: reference
title: Reflecting instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reflecting_instrument
date_saved: 2026-05-05T09:41:54.244254+00:00
instance: kb-cron
parent: reflecting-instrument-20260505-0
summary:
In 1692, Edmond Halley presented the design of a reflecting instrument to the Royal Society. This is an interesting instrument, combining the functionality of a radio latino with a double telescope. The telescope (AB in the adjacent image), has an eyepiece at one end and a mirror (D) partway along its length with one objective lens at the far end (B). The mirror only obstructs half the field (either left or right) and permits the objective to be seen on the other. Reflected in the mirror is the image from the second objective lens (C). This permits the observer to see both images, one straight through and one reflected, simultaneously besides each other. It is essential that the focal lengths of the two objective lenses be the same and that the distances from the mirror to either lens be identical. If this condition is not met, the two images cannot be brought to a common focus. The mirror is mounted on the staff (DF) of the radio latino portion of the instrument and rotates with it. The angle this side of the radio latino's rhombus makes to the telescope can be set by adjusting the rhombus' diagonal length. In order


id: reflecting-instrument-20260505-2
file: data/en.wikipedia.org/wiki/Reflecting_instrument-2.md
category: reference
title: Reflecting instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reflecting_instrument
date_saved: 2026-05-05T09:41:54.244254+00:00
instance: kb-cron
parent: reflecting-instrument-20260505-0
summary:
The origin of the sextant is straightforward and not in dispute. Admiral John Campbell, having used Hadley's octant in sea trials of the method of lunar distances, found that it was wanting. The 90° angle subtended by the arc of the instrument was insufficient to measure some of the angular distances required for the method. He suggested that the angle be increased to 120°, yielding the sextant. John Bird made the first such sextant in 1757. With the development of the sextant, the octant became something of a second class instrument. The octant, while occasionally constructed entirely of brass, remained primarily a wooden-framed instrument. Most of the developments in advanced materials and construction techniques were reserved for the sextant. There are examples of sextants made with wood, however most are made from brass. In order to ensure the frame was stiff, instrument makers used thicker frames. This had a drawback in making the instrument heavier, which could influence the accuracy due to hand-shaking as the navigator worked against its weight. In order to avoid this problem, the frames were modified. Edward Troughton patented the double-framed sextant in 1788. This used two frames held in parallel with spacers. The two frames


id: reflecting-instrument-20260505-3
file: data/en.wikipedia.org/wiki/Reflecting_instrument-3.md
category: reference
title: Reflecting instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reflecting_instrument
date_saved: 2026-05-05T09:41:54.244254+00:00
instance: kb-cron
parent: reflecting-instrument-20260505-0
summary:
The reflecting circle was invented by the German geometer and astronomer Tobias Mayer in 1752, with details published in 1767. His development preceded the sextant and was motivated by the need to create a superior surveying instrument. The reflecting circle is a complete circular instrument graduated to 720° (to measure distances between heavenly bodies, there is no need to read an angle greater than 180°, since the minimum distance will always be less than 180°). Mayer presented a detailed description of this instrument to the Board of Longitude and John Bird used the information to construct one sixteen inches in diameter for evaluation by the Royal Navy. This instrument was one of those used by Admiral John Campbell during his evaluation of the lunar distance method. It differed in that it was graduated to 360° and was so heavy that it was fitted with a support that attached to a belt. It was not considered better than the Hadley octant and was less convenient to use. As a result, Campbell recommended the construction of the sextant. Jean-Charles de Borda further developed the reflecting circle. He modified the position of the telescopic sight in such a way that the mirror could


id: reticle-20260505-0
file: data/en.wikipedia.org/wiki/Reticle-0.md
category: reference
title: Reticle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reticle
date_saved: 2026-05-05T09:41:55.447970+00:00
instance: kb-cron
parent: reticle-20260505-0
summary:
A reticle or reticule, also known as a graticule or crosshair, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, to provide measurement references during visual inspections. Today, engraved lines or embedded fibers may be replaced by a digital image superimposed on a screen or eyepiece. Both terms may be used to describe any set of patterns used for aiding visual measurements and calibrations, but in modern use reticle is most commonly used for weapon sights, while graticule is more widely used for non-weapon measuring instruments such as oscilloscope display, astronomic telescopes, microscopes and slides, surveying instruments and other similar devices. There are many variations of reticle pattern; this article concerns itself mainly with the most rudimentary reticle: the crosshair. Crosshairs are typically represented as a pair of perpendicularly intersecting lines in the shape of a cross, "+", though many variations of additional features exist including dots, posts, concentric circles/horseshoes, chevrons, graduated markings, or a combination of above. Most commonly associated with telescopic sights for aiming firearms, crosshairs are also common in optical instruments used for astronomy


id: reticle-20260505-1
file: data/en.wikipedia.org/wiki/Reticle-1.md
category: reference
title: Reticle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reticle
date_saved: 2026-05-05T09:41:55.447970+00:00
instance: kb-cron
parent: reticle-20260505-0
summary:
=== Reticle focal plane === The reticle may be located at the front or rear focal plane (First Focal Plane (FFP) or Second Focal Plane (SFP)) of the telescopic sight. On fixed power telescopic sights there is no significant difference, but on variable power telescopic sights the front plane reticle remains at a constant size compared to the target, while rear plane reticles remain a constant size to the user as the target image grows and shrinks. Front focal plane reticles are slightly more durable, but most American users prefer that the reticle remains constant as the image changes size, so nearly all modern American variable power telescopic sights are rear focal plane designs. American and European high end optics manufacturers often leave the customer the choice between a FFP or SFP mounted reticle. ==== Collimated reticles ==== Collimated reticles are produced by non-magnifying optical devices such as reflector sights (often called reflex sights) that give the viewer an image of the reticle superimposed over the field of view, and blind collimator sights that are used with both eyes. Collimated reticles are created using refractive or reflective optical collimators to generate a collimated image of an illuminated or reflective reticle.


id: rotational-modulation-collimator-20260505-0
file: data/en.wikipedia.org/wiki/Rotational_modulation_collimator-0.md
category: reference
title: Rotational modulation collimator
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rotational_modulation_collimator
date_saved: 2026-05-05T09:41:56.618148+00:00
instance: kb-cron
parent: rotational-modulation-collimator-20260505-0
summary:
Rotational modulation collimators (or RMCs) are a specialization of the modulation collimator, an imaging device invented by Minoru Oda. Devices of this type create images of high energy X-rays (or other radiations that cast shadows). Since high energy X-rays are not easily focused, such optics have found applications in various instruments. RMCs selectively block and unblock X-rays in a way which depends on their incoming direction, converting image information into time variations. Various mathematical transformations can then reconstitute the image of the source. The Small Astronomy Satellite 3, launched in 1975, was one orbiting experiment that used RMCs. A more recent satellite that used RMCs was RHESSI. == See also == Coded aperture Collimator Modulation == References == RHESSI Imaging Explained


id: santucci-s-armillary-sphere-20260505-0
file: data/en.wikipedia.org/wiki/Santucci's_Armillary_Sphere-0.md
category: reference
title: Santucci's Armillary Sphere
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Santucci's_Armillary_Sphere
date_saved: 2026-05-05T09:41:57.791668+00:00
instance: kb-cron
parent: santucci-s-armillary-sphere-20260505-0
summary:
Santucci's armillary sphere is a Ptolemaic armillary sphere at the Museo Galileo in Florence, the largest existing in the world. Begun on March 4, 1588, and completed on May 6, 1593, this large armillary sphere was built under the supervision of Antonio Santucci at the request of Ferdinand I de' Medici. The sphere represents the "universal machine" of the world according to the concepts developed by Aristotle and perfected by Ptolemy. The terrestrial globe is placed at the center, and it also displays territories that were still relatively little known at the time: notably, it includes both Lake Albert and Lake Victoria in central Africa, which were apparently forgotten again until the explorations of Samuel Baker and John Hanning Speke over 250 years later. The device was restored in the 19th century but is now incomplete and some of its parts are mismatched. The wooden parts of the sphere are elaborately painted and covered with fine gold leaf. The sphere rests on a stand with four sirens. This model is similar to a smaller one built by Santucci in 1582 for King Philip II of Spain, now in the Escorial Library. == References == == Further reading == Meucci, Ferdinando.


id: sextant-20260505-0
file: data/en.wikipedia.org/wiki/Sextant-0.md
category: reference
title: Sextant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sextant
date_saved: 2026-05-05T09:42:00.116585+00:00
instance: kb-cron
parent: sextant-20260505-0
summary:
A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart—for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude (with sight reduction). Sighting the height of a landmark can give a measure of distance off and, held horizontally, a sextant can measure angles between objects for a position on a chart. A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and hence longitude. The principle of the instrument was first implemented around 1731 by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but it was also found later in the unpublished writings of Isaac Newton (1643–1727). In 1922,


id: sextant-20260505-1
file: data/en.wikipedia.org/wiki/Sextant-1.md
category: reference
title: Sextant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sextant
date_saved: 2026-05-05T09:42:00.116585+00:00
instance: kb-cron
parent: sextant-20260505-0
summary:
Attached to the frame are the "horizon mirror", an index arm which moves the index mirror, a sighting telescope, Sun shades, a graduated scale and a micrometer drum gauge for accurate measurements. The scale must be graduated so that the marked degree divisions register twice the angle through which the index arm turns. The scales of the octant, sextant, quintant and quadrant are graduated from below zero to 90°, 120°, 140° and 180° respectively. For example, the sextant illustrated has a scale graduated from −10° to 142°, which is basically a quintant: the frame is a sector of a circle subtending an angle of 76° at the pivot of the index arm. The necessity for the doubled scale reading follows from consideration of the relations of the fixed ray (between the mirrors), the object ray (from the sighted object) and the direction of the normal perpendicular to the index mirror. When the index arm moves by an angle, say 20°, the angle between the fixed ray and the normal also increases by 20°. But the angle of incidence equals the angle of reflection so the angle between the object ray and the normal must also increase by 20°. The angle


id: sextant-20260505-2
file: data/en.wikipedia.org/wiki/Sextant-2.md
category: reference
title: Sextant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sextant
date_saved: 2026-05-05T09:42:00.116585+00:00
instance: kb-cron
parent: sextant-20260505-0
summary:
== Taking a sight == A sight (or measure) of the angle between the Sun, a star, or a planet, and the horizon is done with the 'star telescope' fitted to the sextant using a visible horizon. On a vessel at sea even on misty days a sight may be done from a low height above the water to give a more definite, better horizon. Navigators hold the sextant by its handle in the right hand, avoiding touching the arc with the fingers. For a Sun sight, a filter is used to overcome the glare such as "shades" covering both index mirror and the horizon mirror designed to prevent eye damage. Initially, with the index bar set to zero and the shades covering both mirrors, the sextant is aimed at the sun until it can be viewed on both mirrors through the telescope, then lowered vertically until the portion of the horizon directly below it is viewed on both mirrors. It is necessary to flip back the horizon mirror shade to be able to see the horizon more clearly on it. Releasing the index bar (either by releasing a clamping screw, or on modern instruments, using the quick-release button), and


id: sextant-20260505-3
file: data/en.wikipedia.org/wiki/Sextant-3.md
category: reference
title: Sextant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sextant
date_saved: 2026-05-05T09:42:00.116585+00:00
instance: kb-cron
parent: sextant-20260505-0
summary:
Perpendicularity error This is when the index mirror is not perpendicular to the frame of the sextant. To test for this, place the index arm at about 60° on the arc and hold the sextant horizontally with the arc away from you at arm's length and look into the index mirror. The arc of the sextant should appear to continue unbroken into the mirror. If there is an error, then the two views will appear to be broken. Adjust the mirror until the reflection and direct view of the arc appear to be continuous. Side error This occurs when the horizon glass/mirror is not perpendicular to the plane of the instrument. To test for this, first zero the index arm then observe a star through the sextant. Then rotate the tangent screw back and forth so that the reflected image passes alternately above and below the direct view. If in changing from one position to another, the reflected image passes directly over the unreflected image, no side error exists. If it passes to one side, side error exists. Alternatively, the user can hold the sextant on its side and observe the horizon to check the sextant during the day. If


id: sextant-astronomy-20260505-0
file: data/en.wikipedia.org/wiki/Sextant_(astronomy)-0.md
category: reference
title: Sextant (astronomy)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sextant_(astronomy)
date_saved: 2026-05-05T09:42:01.323619+00:00
instance: kb-cron
parent: sextant-astronomy-20260505-0
summary:
In astronomy, sextants are devices depicting a sixth of a circle, used primarily for measuring the position of stars. There are two types of astronomical sextants, mural instruments and frame-based instruments. They are of significant historical importance, but have been replaced over time by transit telescopes, other astrometry techniques, and satellites such as Hipparcos. == Mural sextants == The first known mural sextant was constructed in Ray, Iran, by Abu-Mahmud al-Khujandi in 994. To measure the obliquity of the ecliptic, al-Khujandī invented a device that he called al-Fakhri sextant (al-suds al Fakhrī), a reference to his patron, Buwayhid ruler, Fakhr al Dawla (976–997). This instrument was a sixty-degree arc on a wall aligned along a meridian (north–south) line. Al Khujandi's instrument was larger than previous instruments; it had a radius of about twenty meters. The main improvement incorporated in al-Fakhri sextants over earlier instruments was bringing the precision of reading to seconds while older instruments could only be read in degrees and minutes. This was confirmed by al-Birūni, al-Marrākushī and al-Kāshī. Al-Khujandī used his device to measure the sun's angle above the horizon at the summer and winter solstices; these two measurements allow computation of the latitude of the sextant's


id: shadow-square-20260505-0
file: data/en.wikipedia.org/wiki/Shadow_square-0.md
category: reference
title: Shadow square
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Shadow_square
date_saved: 2026-05-05T09:42:02.531171+00:00
instance: kb-cron
parent: shadow-square-20260505-0
summary:
The shadow square, also known as an altitude scale, was an instrument used to determine the linear height of an object, in conjunction with the alidade, for angular observations. An early example was described in an Arabic treatise likely dating to 9th or 10th-century Baghdad. Shadow squares are often found on the backs of astrolabes. == Uses == The main use of a shadow square is to measure the linear height of an object using its shadow. It does so by simulating the ratio between an object, generally a gnomon, and its shadow. If the Sun's ray is between 0 degrees and 45 degrees the umbra versa (Vertical axis) is used, between 45 degrees and 90 degrees the umbra recta (Horizontal axis) is used and when the Sun's ray is at 45 degrees its shadow falls exactly on the umbra media (y=x) It was used during the time of medieval astronomy to determine the height of, and to track the movement of celestial bodies such as the Sun when more advanced measurement methods were not available. These methods can still be used today to determine the altitude, with reference to the horizon, of any visible celestial body. == Gnomon ==


id: sine-quadrant-20260505-0
file: data/en.wikipedia.org/wiki/Sine_quadrant-0.md
category: reference
title: Sine quadrant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sine_quadrant
date_saved: 2026-05-05T09:42:03.664274+00:00
instance: kb-cron
parent: sine-quadrant-20260505-0
summary:
A sine quadrant (Arabic: الربع المجيب‎, romanized: rub‘ul mujayyab), sometimes known as a "sinecal quadrant", was a type of quadrant used by medieval Arabic astronomers. The instrument could be used to measure celestial angles, tell time, find directions, perform trigonometric computations, and determine the apparent positions of any celestial object for any time. The name is derived from the Arabic rub meaning 'a quarter' and mujayyab meaning 'marked with sine'. The sine quadrant was described by Muhammad ibn Mūsā al-Khwārizmī in 9th-century Baghdad, and was used throughout the medieval Islamic period to determine the proper times for Islamic prayer. These instruments, with poor angular resolution, were not principally intended to function with stars at night as an astronomical measuring device. It is impractical to sight a star through the front aperture unless it is on a fixed, stabilized mount relative to the half degree width of a very intense Sun. == Description == The instrument is a quarter of a circle made of wood or metal (usually brass) divided on its arc side into 90 equal parts or degrees. The 90 divisions are gathered in 18 groups of five degrees each and are generally numbered both ways from the ends


id: skyscout-20260505-0
file: data/en.wikipedia.org/wiki/SkyScout-0.md
category: reference
title: SkyScout
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SkyScout
date_saved: 2026-05-05T09:42:04.847305+00:00
instance: kb-cron
parent: skyscout-20260505-0
summary:
The Celestron SkyScout was a model of handheld consumer electronic instrument for astronomical orientation and education, similar to the competitor product mySky by Meade Instruments. The general class of zero-magnification sky-orientation scopes using modern geodesy was made possible by the commercialisation of GPS and other GNSS systems in the early 21st century, and the SkyScout was an early example of such use despite being hampered by technical and price limitations. == Specifications == === Hardware === The SkyScout was a handheld, battery powered device about 7.4" x 4.0" x 2.5", and weighing about 1 pound. It had a viewing port, a 3" x 1" LCD on the side and several buttons for controlling and selecting device functions. The SkyScout had a 12 channel GPS receiver and orientation sensors (whose accuracy was sensitive to proximity to metal objects, indicated by a horseshoe magnet icon on the display) that measured location and pointing angle. The LCD screen (known to scratch easily) displayed the name of the object (star, planet, deep sky object, etc.) and other relevant data. An audio presentation was available via earphones on 200 of the most popular celestial objects. Battery life was short at about one-half hour and the


id: solar-telescope-20260505-0
file: data/en.wikipedia.org/wiki/Solar_telescope-0.md
category: reference
title: Solar telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_telescope
date_saved: 2026-05-05T09:42:06.007214+00:00
instance: kb-cron
parent: solar-telescope-20260505-0
summary:
A solar telescope or a solar observatory is a special-purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum. Obsolete names for Sun telescopes include heliograph and photoheliograph. == Professional == Solar telescopes need optics large enough to achieve the best possible diffraction limit but less so for the associated light-collecting power of other astronomical telescopes. However, recently newer narrower filters and higher framerates have also driven solar telescopes towards photon-starved operations. Both the Daniel K. Inouye Solar Telescope as well as the proposed European Solar Telescope (EST) have larger apertures not only to increase the resolution, but also to increase the light-collecting power. Because solar telescopes operate during the day, seeing is generally worse than for night-time telescopes, because the ground around the telescope is heated, which causes turbulence and degrades the resolution. To alleviate this, solar telescopes are usually built on towers and the structures are painted white. The Dutch Open Telescope is built on an open framework to allow the wind to pass through the complete structure and provide cooling around the telescope's main mirror. Another solar telescope-specific problem is the heat generated by the


id: solar-telescope-20260505-1
file: data/en.wikipedia.org/wiki/Solar_telescope-1.md
category: reference
title: Solar telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Solar_telescope
date_saved: 2026-05-05T09:42:06.007214+00:00
instance: kb-cron
parent: solar-telescope-20260505-0
summary:
Solar Terrestrial Relations Observatory (STEREO) mission was launched in October 2006. Two identical spacecraft were launched into orbits that caused them to (respectively) pull further ahead of and fall gradually behind Earth. This enables stereoscopic imaging of the Sun and solar phenomena, such as coronal mass ejections. The Solar Dynamics Observatory was launched in 2010 and monitors the Sun from a geosynchronous orbit around Earth. Parker Solar Probe was launched in 2018 aboard a Delta IV Heavy rocket and will reach a perihelion of 0.046 AU in 2025, making it the closest-orbiting manmade satellite as the first spacecraft to fly low into the solar corona. Solar Orbiter mission (SolO) was launched in 2020 and will reach a minimum perihelion of 0.28 AU, making it the closest satellite with Sun-facing cameras. CubeSat for Solar Particles (CuSP) was launched as a rideshare on Artemis 1 on 16 November 2022 to study particles and magnetic fields. Indian Space Research Organisation has launched a 100 kg satellite named Aditya-L1 on 2 September 2023. Its main instrument will be a coronagraph for studying the dynamics of the solar corona. == Selected solar telescopes == The Einstein Tower (Einsteinturm) became operational in 1924 McMath–Pierce Solar Telescope


id: sophie-chelle-spectrograph-20260505-0
file: data/en.wikipedia.org/wiki/SOPHIE_échelle_spectrograph-0.md
category: reference
title: SOPHIE échelle spectrograph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SOPHIE_échelle_spectrograph
date_saved: 2026-05-05T09:42:07.213775+00:00
instance: kb-cron
parent: sophie-chelle-spectrograph-20260505-0
summary:
The SOPHIE (Spectrographe pour l’Observation des Phénomènes des Intérieurs stellaires et des Exoplanètes, literally meaning "spectrograph for the observation of the phenomena of the stellar interiors and of the exoplanets") échelle spectrograph is a high-resolution echelle spectrograph installed on the 1.93m reflector telescope at the Haute-Provence Observatory located in south-eastern France. The purpose of this instrument is asteroseismology and extrasolar planet detection by the radial velocity method. It builds upon and replaces the older ELODIE spectrograph. This instrument was made available for use by the general astronomical community October 2006. == Characteristics == The electromagnetic spectrum wavelength range is from 387.2 to 694.3 nanometers. The spectrograph is fed from the Cassegrain focus through either one of two separate optical fiber sets, yielding two different spectral resolutions (HE and HR modes). The instrument is entirely computer-controlled. A standard data reduction pipeline automatically processes the data upon every CCD readout cycle. HR mode is the high resolution mode. This mode incorporates a 40 micrometre exit slit to achieve high spectral resolution of R = 75000. HE mode is the high efficiency mode. This mode is used when a higher throughput is desired particularly in the case of faint objects spectral resolution is


id: spectroheliograph-20260505-0
file: data/en.wikipedia.org/wiki/Spectroheliograph-0.md
category: reference
title: Spectroheliograph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spectroheliograph
date_saved: 2026-05-05T09:42:08.444385+00:00
instance: kb-cron
parent: spectroheliograph-20260505-0
summary:
The spectroheliograph is an instrument used in astronomy which captures a photographic image of the Sun at a single wavelength of light, a monochromatic image. The wavelength is usually chosen to coincide with a spectral wavelength of one of the chemical elements present in the Sun. It was developed independently by George Ellery Hale and Henri-Alexandre Deslandres in the 1890s and further refined in 1932 by Robert R. McMath to take motion pictures. The instrument comprises a prism or diffraction grating and a narrow slit that passes a single wavelength (a monochromator). The light is focused onto a photographic medium and the slit is moved across the disk of the Sun to form a complete image. It is now possible to make a filter that transmits a narrow band of wavelengths which produces a similar image, but spectroheliographs remain in use. == See also == Spectrohelioscope Helioscope Heliometer == References == == External links == "Spectroheliograph" . Encyclopædia Britannica. Vol. 25 (11th ed.). 1911. An amateur-made spectroheliograph


id: spectrohelioscope-20260505-0
file: data/en.wikipedia.org/wiki/Spectrohelioscope-0.md
category: reference
title: Spectrohelioscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spectrohelioscope
date_saved: 2026-05-05T09:42:09.572048+00:00
instance: kb-cron
parent: spectrohelioscope-20260505-0
summary:
A spectrohelioscope is a type of solar telescope designed by George Ellery Hale in 1924 to allow the Sun to be viewed in a selected wavelength of light. The name comes from Latin- and Greek-based words: "Spectro," referring to the optical spectrum, "helio," referring to the Sun, and "scope," as in telescope. The basic spectrohelioscope is a complex machine that uses a spectroscope to scan the surface of the Sun. The image from the objective lens is focused on a narrow slit revealing only a thin portion of the Sun's surface. The light is then passed through a prism or diffraction grating to spread the light into a spectrum. The spectrum is then focused on another slit that allows only a narrow part of the spectrum (the desired wavelength of light for viewing) to pass. The light is finally focused on an eyepiece so the surface of the Sun can be seen. The view, however, would be only a narrow strip of the Sun's surface. The slits are moved in unison to scan across the whole surface of the Sun giving a full image. Independently nodding mirrors can be used instead of moving slits to produce the same scan: the


id: spex-astronomy-20260505-0
file: data/en.wikipedia.org/wiki/SPEX_(astronomy)-0.md
category: reference
title: SPEX (astronomy)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SPEX_(astronomy)
date_saved: 2026-05-05T09:42:10.747902+00:00
instance: kb-cron
parent: spex-astronomy-20260505-0
summary:
The SPEX (Spectropolarimeter for Planetary Exploration) is a single-channel, high-precision polarimeter for the characterization of planetary atmospheres. It is intended for planetary science missions, but it could, with minor modifications, also be used for Earth observation by a microsatellite, such as the Dutch FAST-D project. == References == === Cross-reference === === Sources used === == Further reading == Rietjens, J.H.H.; Snik, F.; Stam, D.M.; Smit, J.M.; van Harten, G.; Keller, C.U.; Verlaan, A.L.; Laan, E.C.; ter Horst, R.; Navarro, R.; Wielinga, K.; Moon, S.G.; Voors, R. (2010). SPEX: Spectropolarimeter for Planetary EXploration (PDF). International Conference on Space Optics 4–8 October 2010 Rhodes, Greece. Voors, Robert; Moon, Scott G.; Hannemann, Sandro; Rietjens, Jeroen H. H.; van Harten, Gerard; Snik, Frans; Smit, Martijn; Stam, Daphne M.; Keller, Christoph U.; Laan, Erik C.; Verlaan, Adrianus L.; Vliegenthart, Willem A.; Ter Horst, Rik; Navarro, Ramón; Wielenga, Klaas (2011). Meynart, Roland; Neeck, Steven P.; Shimoda, Haruhisa (eds.). Spectropolarimeter for planetary exploration (SPEX): performance measurements with a prototype (PDF). Proceedings of the SPIE: Sensors, Systems, and Next-Generation Satellites XV. Vol. 8176. pp. 81760D–81760D–12. doi:10.1117/12.897706. van Harten, Gerard; Snik, Frans; Rietjens, Jeroen H. H.; Smit, J. Martijn; de Boer, Jozua; Diamantopoulou, Renia; Hasekamp, Otto P.; Stam,


id: spider-polarimeter-20260505-0
file: data/en.wikipedia.org/wiki/Spider_(polarimeter)-0.md
category: reference
title: Spider (polarimeter)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spider_(polarimeter)
date_saved: 2026-05-05T09:42:11.947346+00:00
instance: kb-cron
parent: spider-polarimeter-20260505-0
summary:
Spider is a balloon-borne experiment designed to search for primordial gravitational waves imprinted on the cosmic microwave background (CMB). Measuring the strength of this signal puts limits on inflationary theory. The Spider instrument consists of six half degree-resolution telescopes cooled to liquid Helium temperature (4 K) which observe at frequencies of 100 GHz, 150 GHz, and 280 GHz (corresponding to wavelengths of 3 mm, 2 mm, and 1.1 mm). Each telescope is coupled to a polarisation-sensitive transition-edge bolometer (TES) array cooled to 300 mK. Spider was the first instrument to successfully demonstrate time-domain multiplexed TES detectors in a space-like environment. At the time of the first flight over Antarctica in 2015, Spider was the most sensitive microwave instrument ever made. The primary science goals include: characterization of the curl-free component of the CMB polarization on the largest scales searching for the signature of inflationary gravitational waves in the CMB polarization characterization of the polarization properties of the emission from our own Milky Way Galaxy The first balloon flight of the experiment launched in January 2015 from McMurdo Station, Antarctica, with support from NASA's Columbia Scientific Balloon Facility. This Long Duration Balloon flight lasted for about 17 days, mapping about 10%


id: stonyhurst-disks-20260505-0
file: data/en.wikipedia.org/wiki/Stonyhurst_disks-0.md
category: reference
title: Stonyhurst disks
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Stonyhurst_disks
date_saved: 2026-05-05T09:42:13.135473+00:00
instance: kb-cron
parent: stonyhurst-disks-20260505-0
summary:
A Stonyhurst disk is a transparent circular grid with lines of solar longitude and latitude that can be overlaid on a solar image to reference the positions of sunspots. This system was originally developed at the Stonyhurst College observatory. == References ==


id: supernova-early-warning-system-20260505-0
file: data/en.wikipedia.org/wiki/SuperNova_Early_Warning_System-0.md
category: reference
title: SuperNova Early Warning System
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SuperNova_Early_Warning_System
date_saved: 2026-05-05T09:42:14.343469+00:00
instance: kb-cron
parent: supernova-early-warning-system-20260505-0
summary:
The SuperNova Early Warning System (SNEWS) is a network of neutrino detectors designed to give early warning to astronomers in the event of a supernova in the Milky Way, our home galaxy, or in a nearby galaxy such as the Large Magellanic Cloud. SNEWS has been operating since 2005. As of March 2021, it has not issued any supernova alerts. This is unsurprising, as supernovae appear to be rare: the most recent known supernova remnant in the Milky Way was around the turn of the 20th century, and the most recent Milky Way supernova confirmed to have been observed was Kepler's Supernova in 1604. == SNEWS 2.0 == In June 2019 a "SNEWS 2.0" workshop was held at Laurentian University of Sudbury in Canada, focused on plans for an update of SNEWS. As the result, an upgraded system was devised under the name "SNEWS 2.0". == Neutrino detection == Powerful bursts of electron neutrinos (νe) with typical energies of the order of 10 MeV and duration of the order of 10 seconds are produced in the core of a red giant star as it collapses on itself via the "neutronization" reaction, i.e. fusion of protons and electrons into neutrons and


id: sutton-armillary-20260505-0
file: data/en.wikipedia.org/wiki/Sutton_armillary-0.md
category: reference
title: Sutton armillary
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sutton_armillary
date_saved: 2026-05-05T09:42:15.631352+00:00
instance: kb-cron
parent: sutton-armillary-20260505-0
summary:
The Millennium Dial Armillary is one of six pieces of public art located in the town centre of Sutton in Greater London, England. The others include the Sutton heritage mosaic, the Sutton twin towns mural and the Messenger statue. The armillary was dedicated to the town in 2000 by the Rotary Club, and is in the form of a historical timepiece. It serves three purposes: firstly, simply to tell the time; secondly, to commemorate time through various inscriptions including the Rotary motto "Service Above Self" and distances to nearby areas such as Kingston upon Thames; and thirdly, to commemorate the work which the Rotary Club has done. == Inscription == The inscription on the plinth reads as follows: "Service Above Self" Rotary Armillary This Armillary was presented to the people of the London Borough of Sutton in grateful thanks for their generosity in supporting Rotary Charities and to mark the new Millennium. The Rotary Club of Cheam has joined with the Rotary Clubs of Carshalton, Carshalton Beeches, Sutton, Sutton Nonsuch and Wallington. December 2000 The Project was made possible by the following Sponsors: Securicor plc. Holiday Inn Sutton London. The Crown Agents. South Sutton Neighbourhood Association. Sutton & Cheam Society.


id: swiss-1-2-metre-leonhard-euler-telescope-20260505-0
file: data/en.wikipedia.org/wiki/Swiss_1.2-metre_Leonhard_Euler_Telescope-0.md
category: reference
title: Swiss 1.2-metre Leonhard Euler Telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Swiss_1.2-metre_Leonhard_Euler_Telescope
date_saved: 2026-05-05T09:42:16.835986+00:00
instance: kb-cron
parent: swiss-1-2-metre-leonhard-euler-telescope-20260505-0
summary:
Leonhard Euler Telescope, or the Swiss EULER Telescope, is a national, fully automatic 1.2-metre (47 in) reflecting telescope, built and operated by the Geneva Observatory. It is located at an altitude of 2,375 m (7,792 ft) at ESO's La Silla Observatory site in the Chilean Norte Chico region, about 460 kilometers north of Santiago de Chile. The telescope, which saw its first light on 12 April 1998, is named after Swiss mathematician Leonhard Paul Euler. The Euler telescope uses the CORALIE instrument to search for exoplanets. In addition, the telescope uses the multi-purpose EulerCam (ecam), a high precision photometry instrument, and a smaller, piggyback mounted telescope, called "Pisco". Its first discovery was a planet in orbit around Gliese 86, determined to be a hot Jupiter with an orbital period of only 15.8 earth days and about four times the mass of Jupiter. Since then, many other exoplanets have been discovered or examined in follow-up observations. Together with the Mercator Telescope, Euler was part of the Southern Sky extrasolar Planet search Programme, which has discovered numerous extrasolar planets. It has also been frequently employed for follow-up characterization to determine the mass of exoplanets discovered by the Wide Angle Search for Planets,


id: telecompressor-20260505-0
file: data/en.wikipedia.org/wiki/Telecompressor-0.md
category: reference
title: Telecompressor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Telecompressor
date_saved: 2026-05-05T09:42:17.974207+00:00
instance: kb-cron
parent: telecompressor-20260505-0
summary:
A telecompressor or focal reducer is an optical element used to reduce focal length, increase lens speed, and in some instances improve optical transfer function (OTF) performance. It is also widely known under the name “Speed Booster”, which is the commercial name of a line of telecompressors by the manufacturer Metabones. Popular applications include photography, videography, and astrophotography. In astrophotography, these qualities are most desirable when taking pictures of nearby large objects, such as nebulae. The effects and uses of the telecompressor are largely opposite to those of the teleconverter or Barlow lens. A combined system of a lens and a focal reducer has smaller back focus than the lens alone; this places restrictions on lenses and cameras that focal reducer might be used with. Lens adapters that include telecompressors are useful with digital mirrorless cameras. By combining a telecompressor within a lens adapter, mirrorless cameras can use the lenses of both digital single-lens reflex cameras (DSLRs) and film-based SLR (Single-lens reflex cameras). == Calculating focal reduction == For a refractor telescope or simple camera lens, the new effective focal length fn is given by: f n = f o ( 1 − d f r ) , {\displaystyle {f_{n}}={f_{o}}\left(1-{\frac


id: tellurion-20260505-0
file: data/en.wikipedia.org/wiki/Tellurion-0.md
category: reference
title: Tellurion
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tellurion
date_saved: 2026-05-05T09:42:20.330771+00:00
instance: kb-cron
parent: tellurion-20260505-0
summary:
A tellurion (also spelled tellurian, tellurium, and yet another name is loxocosm), is a clock, typically of French or Swiss origin, surmounted by a mechanism that depicts how day, night, and the seasons are caused by the rotation and orientation of Earth on its axis and its orbit around the Sun. The clock normally also displays the phase of the Moon and the four-year (perpetual) calendar. It is related to the orrery, which illustrates the relative positions and motions of the planets and moons in the Solar System in a heliocentric model. The word tellurion derives from the Latin tellus, meaning "earth". == See also == Astronomical clock Solar System models == References == == External links ==


id: torquetum-20260505-0
file: data/en.wikipedia.org/wiki/Torquetum-0.md
category: reference
title: Torquetum
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Torquetum
date_saved: 2026-05-05T09:42:21.555663+00:00
instance: kb-cron
parent: torquetum-20260505-0
summary:
The torquetum or turquet is a medieval astronomical instrument for taking and converting measurements made in three sets of coordinates: horizon, equatorial, and ecliptic. It is characterised by R. P. Lorch as a combination of Ptolemy's astrolabon (Greek: αστρολάβον) and the plane astrolabe. In a sense, the torquetum is an analog computer. == Invention == The origins of the torquetum are unclear. Its invention has been credited to multiple figures, including Jabir ibn Aflah, Bernard of Verdun and Franco of Poland. In 1469, Regiomontanus credited an 11th-century Arab astronomer from Seville, Jabir ibn Aflah. Later, in 1598, Tycho Brahe speculated that it was a 12th-century creation of "Arabians or Chaldeans." Eventually, early 20th-century German historians shifted the attribution to the "Turks." Jabir ibn Aflah of Al-Andalus in the early 12th century has been assumed by several historians to be the inventor of the torquetum, based on a similar instrument he described in his Islah Almajisti. However, while his device is similar in function, it has not been identified as a torquetum, but evidence suggests it inspired the torquetum. According to Joseph Needham, a simplified version of the torquetum was among the instruments documented at the imperial Chinese observatory of the


id: torquetum-20260505-1
file: data/en.wikipedia.org/wiki/Torquetum-1.md
category: reference
title: Torquetum
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Torquetum
date_saved: 2026-05-05T09:42:21.555663+00:00
instance: kb-cron
parent: torquetum-20260505-0
summary:
== Components == The torquetum is a complex medieval analog computer that measures three sets of astronomical coordinates: the horizon, equatorial, and ecliptic. One of the defining attributes of the torquetum is its ability to interconvert between these three sets of coordinate dimensions without the use of calculations, as well as to demonstrate the relationship between the same coordinate sets. However, it is a device that requires a thorough understanding of the components and how they work together to make relative positional measurements of certain celestial objects. The anatomy of the torquetum involves many different components, which can be grouped into subdivisions of the torquetum structure, those being: the base, the midframe, and the upperframe. The base starts with the tabula orizontis, which is the bottommost rectangular piece in contact with the ground, and this component represents the horizon of the Earth, relative to the point of measurement. Hinged to the tabula orizontis is a similarly shaped component, the tabula equinoctialis, which represents the latitude of the Earth. This piece can rotate up to 90 degrees, coinciding with the latitudinal lines of the Earth from the equator to the poles. This angle of rotation is created by the stylus, which


id: triquetrum-astronomy-20260505-0
file: data/en.wikipedia.org/wiki/Triquetrum_(astronomy)-0.md
category: reference
title: Triquetrum (astronomy)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Triquetrum_(astronomy)
date_saved: 2026-05-05T09:42:22.798000+00:00
instance: kb-cron
parent: triquetrum-astronomy-20260505-0
summary:
The triquetrum (derived from the Latin tri- 'three' and quetrum 'cornered') was the medieval name for an ancient astronomical instrument first described by Ptolemy (c. 90 – c. 168) in the Almagest (V. 12). Also known as Parallactic Rulers, it was used for determining altitudes of heavenly bodies. Ptolemy calls it a "parallactic instrument" and seems to have used it to determine the zenith distance and parallax of the Moon. == Design == The triquetrum performed the same function as the quadrant and was devised to overcome the difficulty of graduating arcs and circles. It consisted of a vertical post with a graduated scale and two pivoted arms hinged at the top and bottom, the upper arm carrying sights. The two arms were joined so that their ends could slide. As a person sighted along the upper arm, the lower one changed its angle. By reading the position of the lower rod, in combination with the vertical length, the zenith distance (or, alternatively, the altitude) of a celestial object could be calculated. == Use == The triquetrum was one of the most popular astronomical instruments until the invention of the telescope, it could measure angles with a better precision than


id: verona-astrolabe-20260505-0
file: data/en.wikipedia.org/wiki/Verona_astrolabe-0.md
category: reference
title: Verona astrolabe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Verona_astrolabe
date_saved: 2026-05-05T09:42:24.032256+00:00
instance: kb-cron
parent: verona-astrolabe-20260505-0
summary:
The Verona astrolabe is an archaeological discovery unearthed in the vaults of a museum in Verona, Italy. Dating back to the eleventh century, this Islamic astrolabe is one of the oldest examples of its kind and is among the few known to exist worldwide. It appears to have been employed by Muslim, Jewish, and Christian communities spanning Spain, North Africa, and Italy over several centuries. Described by historian Tom Almeroth-Williams of the University of Cambridge as the "world's first smartphone," the astrolabe served as a portable astronomical instrument capable of diverse functionalities. It provided users with a two-dimensional representation of the universe, enabling the plotting of star positions, calculation of time and distances, and even the development of horoscopes. Initially doubted to be authentic, the Verona Astrolabe was authenticated as an eleventh-century artifact by Dr. Federica Gigante of Cambridge University's History Faculty. Her analysis, published in the journal Nuncius, confirmed its origins in Al-Andalus, the Muslim-ruled region of Spain during the medieval period. The astrolabe bears Hebrew inscriptions alongside Arabic, indicating its circulation within the Jewish diaspora community in Italy, where Hebrew was used in place of Arabic. == References ==


id: visible-multi-object-spectrograph-20260505-0
file: data/en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph-0.md
category: reference
title: Visible Multi Object Spectrograph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph
date_saved: 2026-05-05T09:42:25.209834+00:00
instance: kb-cron
parent: visible-multi-object-spectrograph-20260505-0
summary:
The Visible Multi-Object Spectrograph (VIMOS) is a wide field imager and a multi-object spectrograph installed at the European Southern Observatory's Very Large Telescope (VLT), in Chile. The instrument used for deep astronomical surveys delivers visible images and spectra of up to 1,000 galaxies at a time. VIMOS images four rectangular areas of the sky, 7 by 8 arcminutes each, with gaps of 2 arcminutes between them. Its principal investigator was Olivier Le Fèvre. The Franco-Italian instrument operates in the visible part of the spectrum from 360 to 1000 nanometers (nm). In the conceptual design phase, the multi-object spectrograph then called VIRMOS included an additional instrument, NIMOS, operating in the near-infrared spectrum of 1100–1800 nm. Operating in the three different observation modes, direct imaging, multi-slit spectroscopy, and integral field spectroscopy, the main objective of the instrument is to study the early universe through massive redshift surveys, such as the VIMOS-VLT Deep Survey. VIMOS saw its first light on 26 February 2002, and has since been mounted on the Nasmyth B focus of VLT's Melipal unit telescope (UT3). It was retired in 2018 to make space for the return of CRIRES+. == Gallery == == See also == List of instruments at


id: volvelle-20260505-0
file: data/en.wikipedia.org/wiki/Volvelle-0.md
category: reference
title: Volvelle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Volvelle
date_saved: 2026-05-05T09:42:26.363356+00:00
instance: kb-cron
parent: volvelle-20260505-0
summary:
A volvelle or wheel chart is a type of slide chart, a paper construction with rotating parts. It is considered an early example of a paper analog computer. Volvelles have been produced to accommodate organization and calculation in many diverse subjects. Early examples of volvelles are found in the pages of astronomy books. A moveable device for working out the position of the sun and moon in the zodiac is known as a volvella. == 20th century == In the twentieth century, the volvelle had many diverse uses. In Reinventing the Wheel, author Jessica Helfand introduces twentieth-century volvelles with this: The twentieth century saw a robust growth in the design, manufacture, and production of a new generation of independent, free-standing volvelles. Categorically, they not only represent an unusually eclectic set of uses, but demonstrate, too, a remarkable range of stylistic, compositional, mechanical, informational, and kinetic conceits. There are volvelles that arrange their data peripherally, centrifugally, and radially; volvelles that use multiple concentric circles with pointers; and volvelles that benefit from the generous use of the die-cut, a particular technological hallmark of modern printing manufacture. Twentieth-century volvelles—often referred to as wheel charts—offer everything from inventory control to color calibration, mileage metering


id: warkworth-radio-astronomical-observatory-20260505-0
file: data/en.wikipedia.org/wiki/Warkworth_Radio_Astronomical_Observatory-0.md
category: reference
title: Warkworth Radio Astronomical Observatory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Warkworth_Radio_Astronomical_Observatory
date_saved: 2026-05-05T09:42:27.517774+00:00
instance: kb-cron
parent: warkworth-radio-astronomical-observatory-20260505-0
summary:
The Warkworth Radio Astronomical Observatory is a radio telescope observatory, located just south of Warkworth, New Zealand, about 50 km north of the Auckland CBD. It was established by the Institute for Radio Astronomy and Space Research, Auckland University of Technology. The WARK12M 12m Radio Telescope was constructed in 2008. In 2010, a licence to operate the Telecom New Zealand 30m dish was granted, which led to the commissioning of the WARK30M 30m Radio Telescope. The first observations made in conjunction with the Australian Long Baseline Array took place in 2011. The observatory was purchased by Space Operations New Zealand Limited (SpaceOps NZ) in July 2023 after the university decided to close the facility. Because of its wider ambit, the facility is now called the Warkworth Space Centre. == History == The Warkworth Space Centre is on land that was first developed for long-range telecommunications, operated by the New Zealand Post Office and opening on 17 July 1971. The station, primarily connecting to fourth generation Intelsat satellites, was used for satellite telephone circuits and television, including the broadcast of the 1974 British Commonwealth Games, held in Christchurch. The shallow valley site was chosen as it was sheltered from winds and


id: warkworth-radio-telescope-20260505-0
file: data/en.wikipedia.org/wiki/Warkworth_Radio_Telescope-0.md
category: reference
title: Warkworth Radio Telescope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Warkworth_Radio_Telescope
date_saved: 2026-05-05T09:42:28.752570+00:00
instance: kb-cron
parent: warkworth-radio-telescope-20260505-0
summary:
The Warkworth 12m Radio Telescope is a radio telescope at the Warkworth Radio Astronomical Observatory, located just south of Warkworth, New Zealand, about 50 km north of the Auckland CBD. It is operated by the Institute of Radio Astronomy and Space Research of Auckland University of Technology and was constructed in 2008. == Technical information == The 12m diameter antenna was designed and constructed by COBHAM Satcom. The antenna is a fully steerable dual shaped Cassegrain with a main dish diameter of 12.1m and a secondary reflector diameter of 1.8m. The focal Length is 4.538m. The surface precision is 0.35mm (RMS) and the pointing accuracy is 18 inches. It operates in the L-Band, S-Band and X-Band with dual polarisation S and X-band feeds from COBHAM with room temperature receivers. The receiver systems cover 2.2 to 2.4 GHz at S-band and 8.1 to 9.1 GHz at X-band. It is mounted alt-azimuth and has slewing rates of 5 deg/s in azimuth and 1.25 deg/s in elevation, and acceleration of 1.3 deg/s/s. == Research activity == In 2010 this dish was used for several very-long-baseline interferometry(VLBI) observations in conjunction with the Australian Long Baseline Array. From 2011 it was a part of the


id: double-violin-20260505-0
file: data/en.wikipedia.org/wiki/Double_violin-0.md
category: reference
title: Double violin
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Double_violin
date_saved: 2026-05-05T09:42:31.335988+00:00
instance: kb-cron
parent: double-violin-20260505-0
summary:
The Double Violin is a ten-string, stereophonic double-necked electric violin invented by violinist L. Shankar. It is also referred to as the LSD or L. Shankar's Double Violin. == Description == The double violin is capable of replicating a full orchestra's effect with the lower neck covering the double bass and cello range, and the upper neck generating treble sounds; the violin and viola. In addition to providing a wide range of five and a half octaves, playing on one neck produces a sympathetic resonance effect on the other. The horizontal rib can be positioned beneath the chin or supported against the chest (Indian style) while playing. Due to the instrument's greater angle, the bowing was different and Shankar incorporated new techniques including playing on both necks simultaneously. The concept for the double violin originated in 1978, after producing his album by Zappa Records where Shankar had to overdub a wide range of string instruments as he was unable to find session musicians who could render the Indian ornaments and styles he wanted. He made a prototype with cardboard and spent about a year and a half improving the design. To date, Shankar has commissioned four different versions of the


id: electricity-meter-20260505-0
file: data/en.wikipedia.org/wiki/Electricity_meter-0.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
An electricity meter, electric meter, electrical meter, energy meter, kilowatt-hour meter, or power meter is a device that measures the amount of electric energy consumed by a residence, a business, or an electrically powered device over a time interval. Electric utilities use electric meters installed at customers' premises for billing and monitoring purposes. They are typically calibrated in billing units, the most common one being the kilowatt hour (kWh). They are usually read once each billing period. When energy savings during certain periods are desired, some meters may measure demand, the maximum use of power in some interval. "Time of day" metering allows electric rates to be changed during a day, to record usage during peak high-cost periods and off-peak, lower-cost, periods. Also, in some areas meters have relays for demand response load shedding during peak load periods. == History == The earliest commercial uses of electric energy, in the 1880s, had easily predictable usage; billing was based on the number of lamps or motors installed in a building. However, as usage spread, and especially with the invention of pluggable appliances, it also became more variable, and the electric utilities sought a means to bill customers based on actual rather


id: electricity-meter-20260505-1
file: data/en.wikipedia.org/wiki/Electricity_meter-1.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
The most common unit of measurement on the electricity meter is the kilowatt hour [kWh], which is equal to the amount of energy used by a load of one kilowatt over a period of one hour, or 3,600,000 joules. Some electricity companies use the SI megajoule instead. Demand is normally measured in watts, but averaged over a period, most often a quarter- or half-hour. Reactive power is measured in "thousands of volt-ampere reactive-hours", (kvarh). By convention, a "lagging" or inductive load, such as a motor, will have positive reactive power. A "leading", or capacitive load, will have negative reactive power. Volt-amperes measures all power passed through a distribution network, including reactive and actual. This is equal to the product of root-mean-square volts and amperes. Distortion of the electric current by loads is measured in several ways. Power factor is the ratio of resistive (or real) power to volt-amperes. A capacitive load has a leading power factor, and an inductive load has a lagging power factor. A purely resistive load (such as a filament lamp, heater or kettle) exhibits a power factor of 1. Current harmonics are a measure of distortion of the wave form. For example, electronic loads such as


id: electricity-meter-20260505-2
file: data/en.wikipedia.org/wiki/Electricity_meter-2.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
t = time in seconds taken by the disc to complete one revolution, P = power in watts. For example, if Kh = 7.2 as above, and one revolution took place in 14.4 seconds, the power is 1800 watts. This method can be used to determine the power consumption of household devices by switching them on one by one. Most domestic electricity meters must be read manually, whether by a representative of the power company or by the customer. Where the customer reads the meter, the reading may be supplied to the power company by telephone, post or over the internet. The electricity company will normally require a visit by a company representative at least annually in order to verify customer-supplied readings and to make a basic safety check of the meter. In an induction type meter, creep is a phenomenon that can adversely affect accuracy, that occurs when the meter disc rotates continuously with potential applied and the load terminals open circuited. A test for error due to creep is called a creep test. Two standards govern meter accuracy, ANSI C12.20 for North America and IEC 62053. === Electronic === Electronic meters display the energy used on an LCD


id: electricity-meter-20260505-3
file: data/en.wikipedia.org/wiki/Electricity_meter-3.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
EN 62053-31 (formerly DIN 43864) defines the S0 interface, which is a galvanically isolated open collector output. Voltage and current are limited to 27 V and 27 mA, respectively. Each metered amount of electrical energy produces one impulse with a length of 32-100 ms. The meter constant (pulses per kWh) is programmable on some meters, but often fixed to 1000-10000 pulses per kWh. Other meters implement a similar pulse interface, but with an infrared LED instead of an electrical connection. The interface is also used on other kinds of meters, like water meters. Many meters designed for semi-automated reading have a serial port that communicates by infrared LED through the faceplate of the meter. In some multi-unit buildings, a similar protocol is used, but in a wired bus using a serial current loop to connect all the meters to a single plug. The plug is often near a more easily accessible point. In the European Union, the most common infrared and protocol is "FLAG", a simplified subset of mode C of IEC 61107. In the United States and Canada, the favored infrared protocol is ANSI C12.18. Some industrial meters use protocols for programmable logic controllers, like Modbus or DNP3. One


id: electricity-meter-20260505-4
file: data/en.wikipedia.org/wiki/Electricity_meter-4.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
Radio-activated switching is common in the UK, with a nightly data signal sent within the longwave carrier of BBC Radio 4, 198 kHz. The time of off-peak charging is usually seven hours between midnight and 7:00am GMT/BST, and this is designed to power storage heaters and immersion heaters. In the UK, such tariffs are typically branded Economy 7, White Meter or Dual-Rate. The popularity of such tariffs has declined in recent years, at least in the domestic market, because of the (perceived or real) deficiencies of storage heaters and the comparatively much lower cost of natural gas per kWh (typically a factor of 3-5 times lower). Nevertheless, a sizeable number of properties do not have the option of gas, with many in rural areas being outside the gas supply network, and others being expensive upfront to upgrade to a radiator system. An Economy 10 meter is also available, which gives 10 hours of cheap off-peak electricity spread out over three timeslots throughout a 24-hour period. This allows multiple top-up boosts to storage heaters, or a good spread of times to run a wet electric heating system on a cheaper electricity rate. Most meters using Economy 7 switch the entire electricity


id: electricity-meter-20260505-5
file: data/en.wikipedia.org/wiki/Electricity_meter-5.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
=== Time of day metering === Time of Day metering (TOD), also known as Time of Usage (TOU) or Seasonal Time of Day (SToD), metering involves dividing the day, month and year into tariff slots and with higher rates at peak load periods and low tariff rates at off-peak load periods. While this can be used to automatically control usage on the part of the customer (resulting in automatic load control), it is often simply the customer's responsibility to control his own usage or pay accordingly (voluntary load control). This also allows the utilities to plan their transmission infrastructure appropriately. See also Demand-side Management (DSM). TOD metering normally splits rates into an arrangement of multiple segments including on-peak, off-peak, mid-peak or shoulder, and critical peak. A typical arrangement is a peak occurring during the day (non-holiday days only), such as from 1 pm to 9 pm Monday through Friday during the summer and from 6:30 am to 12 noon and 5 pm to 9 pm during the winter. More complex arrangements include the use of critical peaks that occur during high demand periods. The times of peak demand/cost will vary in different markets around the world. Large commercial users can


id: electricity-meter-20260505-6
file: data/en.wikipedia.org/wiki/Electricity_meter-6.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
=== Customer drop and metering equation === Since electrical standards vary in different regions, "customer drops" from the grid to the customer also vary depending on the standards and the type of installation. There are several common types of connections between a grid and a customer. Each type has a different metering equation. Blondel's theorem states that for any system with N current-carrying conductors, that N-1 measuring elements are sufficient to measure electrical energy. This indicates that different metering is needed, for example, for a three-phase three-wire system than for a three-phase four-wire (with neutral) system. In Europe, Asia, Africa and most other locations, single phase is common for residential and small commercial customers. Single phase distribution is less-expensive, because one set of transformers in a substation normally serve a large area with relatively high voltages (usually 230 V) and no local transformers. These have a simple metering equation: Watts = volts x amps, with volts measured from the neutral to the phase wire. In the United States, Canada, and parts of Central and South America similar customers are normally served by three-wire single phase. Three-wire single-phase requires local transformers, as few as one per ten residences, but provides lower,


id: electricity-meter-20260505-7
file: data/en.wikipedia.org/wiki/Electricity_meter-7.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
== Tampering and security == Meters can be manipulated to make them under-register, effectively allowing power use without paying for it. Power companies often install remote-reporting meters specifically to enable remote detection of tampering, and specifically to discover energy theft. The change to smart power meters is useful to stop energy theft. When tampering is detected, the normal tactic, legal in most areas of the United States, is to switch the subscriber to a "tampering" tariff charged at the meter's maximum designed current. At US$0.095/kWh, a standard residential 50 A meter causes a legally collectible charge of about US$5,000.00 per month. Meter readers are trained to spot signs of tampering, and with crude mechanical meters, the maximum rate may be charged each billing period until the tamper is removed, or the service is disconnected. A common method of tampering on mechanical disk meters is to attach magnets to the outside of the meter. Strong magnets saturate the magnetic fields in the meter so that the motor portion of a mechanical meter does not operate. Lower power magnets can add to the drag resistance of the internal disk resistance magnets. Magnets can also saturate current transformers or power-supply transformers in electronic


id: electricity-meter-20260505-8
file: data/en.wikipedia.org/wiki/Electricity_meter-8.md
category: reference
title: Electricity meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electricity_meter
date_saved: 2026-05-05T09:42:32.585250+00:00
instance: kb-cron
parent: electricity-meter-20260505-0
summary:
== Regulation and legislation == Following the deregulation of electricity supply markets in many countries, the company responsible for an electricity meter may not be obvious. Depending on the arrangements in place, the meter may be the property of the meter Operator, electricity distributor, the retailer or for some large users of electricity the meter may belong to the customer. The company responsible for reading the meter may not always be the company which owns it. Meter reading is now sometimes subcontracted and in some areas the same person may read gas, water and electricity meters at the same time. The introduction of advanced meters in residential areas has produced additional privacy issues that may affect ordinary customers. These meters are often capable of recording energy usage every 15, 30 or 60 minutes. Some meters have one or two IR LEDs on the front: one used for testing and which acts as the equivalent of the timing mark on the older mechanical meters and the other as part of a two-way IR communications port for reading / programming the meter. These IR LEDs are visible with some night vision viewers and certain video cameras that are capable of sensing IR


id: electrophorus-20260505-0
file: data/en.wikipedia.org/wiki/Electrophorus-0.md
category: reference
title: Electrophorus
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electrophorus
date_saved: 2026-05-05T09:42:33.988574+00:00
instance: kb-cron
parent: electrophorus-20260505-0
summary:
In electromagnetism, an electrophorus or electrophore is a simple, manual, capacitive, electrostatic generator used to produce charge via the process of electrostatic induction. A first version of it was invented in 1762 by Swedish professor Johan Carl Wilcke. Italian scientist Alessandro Volta improved and popularized the device in 1775, and is sometimes erroneously credited with its invention. The word electrophorus was coined by Volta from the Greek ήλεκτρον, elektron, and φορεύς, phoreus, meaning 'electricity bearer'. == Description and operation == The electrophorus consists of a dielectric plate (originally a 'cake' of resinous material such as pitch or wax, but in modern versions plastic is used) and a metal plate with an insulating handle. The dielectric plate is first charged through the triboelectric effect by rubbing it with fur or cloth. For this discussion, imagine the dielectric gains negative charge by rubbing, as in the illustration below. The metal plate is then placed onto the dielectric plate. The dielectric does not transfer a significant fraction of its surface charge to the metal because the microscopic contact is poor. Instead the electrostatic field of the charged dielectric causes the charges in the metal plate to separate. It develops two regions of charge


id: electroscope-20260505-0
file: data/en.wikipedia.org/wiki/Electroscope-0.md
category: reference
title: Electroscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electroscope
date_saved: 2026-05-05T09:42:35.181897+00:00
instance: kb-cron
parent: electroscope-20260505-0
summary:
The electroscope is an early scientific instrument used to detect the presence of electric charge on a body. It detects this by the movement of a test charge due to the Coulomb electrostatic force on it. The amount of charge on an object is proportional to its voltage. The accumulation of enough charge to detect with an electroscope requires hundreds or thousands of volts, so electroscopes are used with high voltage sources such as static electricity and electrostatic machines. An electroscope can only give a rough indication of the quantity of charge; an instrument that measures electric charge quantitatively is called an electrometer. The electroscope was the first electrical measuring instrument. The first electroscope was a pivoted needle (called the versorium), invented by British physician William Gilbert around 1600. The pith-ball electroscope and the gold-leaf electroscope are two classical types of electroscope that are still used in physics education to demonstrate the principles of electrostatics. A type of electroscope is also used in the quartz fiber radiation dosimeter. Electroscopes were used by the Austrian scientist Victor Hess in the discovery of cosmic rays. == Pith-ball electroscope == In 1731, Stephen Gray used a simple hanging thread, which would be attracted


id: electroscope-20260505-1
file: data/en.wikipedia.org/wiki/Electroscope-1.md
category: reference
title: Electroscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Electroscope
date_saved: 2026-05-05T09:42:35.181897+00:00
instance: kb-cron
parent: electroscope-20260505-0
summary:
The gold-leaf electroscope was developed in 1787 by British clergyman and physicist Abraham Bennet, as a more sensitive instrument than pith ball or straw blade electroscopes then in use. It consists of a vertical metal rod, usually brass, from the end of which hang two parallel strips of thin flexible gold leaf. A disk or ball terminal is attached to the top of the rod, where the charge to be tested is applied. To protect the gold leaves from drafts of air they are enclosed in a glass bottle, usually open at the bottom and mounted over a conductive base. Often there are grounded metal plates or foil strips in the bottle flanking the gold leaves on either side. These are a safety measure; if an excessive charge is applied to the delicate gold leaves, they will touch the grounding plates and discharge before tearing. They also capture charge leaking through the air that accumulates on the glass walls, increasing the sensitivity of the instrument. In the precision instruments the inside of the bottle was occasionally evacuated, to prevent the charge on the terminal from leaking off through the ionization of the air. When the metal terminal is touched with


id: galvanometer-20260505-0
file: data/en.wikipedia.org/wiki/Galvanometer-0.md
category: reference
title: Galvanometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galvanometer
date_saved: 2026-05-05T09:42:36.412179+00:00
instance: kb-cron
parent: galvanometer-20260505-0
summary:
A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. Galvanometers work by deflecting a pointer in response to an electric current flowing through a coil in a constant magnetic field. The mechanism is also used as an actuator in applications such as hard disks. Galvanometers came from the observation, first noted by Hans Christian Ørsted in 1820, that a magnetic compass's needle deflects when near a wire having electric current. They were the first instruments used to detect and measure small amounts of current. André-Marie Ampère, who gave mathematical expression to Ørsted's discovery, named the instrument after the Italian electricity researcher Luigi Galvani, who in 1791 discovered the principle of the frog galvanoscope – that electric current would make the legs of a dead frog jerk. Galvanometers have been essential for the development of science and technology in many fields. For example, in the 1800s they enabled long-range communication through submarine cables, such as the earliest transatlantic telegraph cables, and were essential to discovering the electrical activity of the heart and brain, by their fine measurements of current. Galvanometers


id: galvanometer-20260505-1
file: data/en.wikipedia.org/wiki/Galvanometer-1.md
category: reference
title: Galvanometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galvanometer
date_saved: 2026-05-05T09:42:36.412179+00:00
instance: kb-cron
parent: galvanometer-20260505-0
summary:
=== Modern uses === Most modern uses for the galvanometer mechanism are in positioning and control systems. Galvanometer mechanisms are divided into moving magnet and moving coil galvanometers; in addition, they are divided into closed-loop and open-loop - or resonant - types. Mirror galvanometer systems are used as beam positioning or beam steering elements in laser scanning systems. For example, for material processing with high-power lasers, closed loop mirror galvanometer mechanisms are used with servo control systems. These are typically high power galvanometers and the newest galvanometers designed for beam steering applications can have frequency responses over 10 kHz with appropriate servo technology. Closed-loop mirror galvanometers are also used in similar ways in stereolithography, laser sintering, laser engraving, laser beam welding, laser TVs, laser displays and in imaging applications such as retinal scanning with Optical Coherence Tomography (OCT) and Scanning Laser Ophthalmoscopy (SLO). Almost all of these galvanometers are of the moving magnet type. The closed loop is obtained measuring the position of the rotating axis with an infrared emitter and 2 photodiodes. This feedback is an analog signal. Open loop, or resonant mirror galvanometers, are mainly used in some types of laser-based bar-code scanners, printing machines, imaging applications, military


id: galvanometer-20260505-2
file: data/en.wikipedia.org/wiki/Galvanometer-2.md
category: reference
title: Galvanometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galvanometer
date_saved: 2026-05-05T09:42:36.412179+00:00
instance: kb-cron
parent: galvanometer-20260505-0
summary:
Edward Weston extensively improved the design of the galvanometer. He substituted the fine wire suspension with a pivot and provided restoring torque and electrical connections through spiral springs rather than through the traditional wristwatch balance wheel hairspring. He developed a method of stabilizing the magnetic field of the permanent magnet, so the instrument would have consistent accuracy over time. He replaced the light beam and mirror with a knife-edge pointer that could be read directly. A mirror under the pointer, in the same plane as the scale, eliminated parallax observation error. To maintain the field strength, Weston's design used a very narrow circumferential slot through which the coil moved, with a minimal air-gap. This improved linearity of pointer deflection with respect to coil current. Finally, the coil was wound on a lightweight form made of conductive metal, which acted as a damper. By 1888, Edward Weston had patented and brought out a commercial form of this instrument, which became a standard electrical equipment component. It was known as a "portable" instrument because it was affected very little by mounting position or by transporting it from place to place. This design is almost universally used in moving-coil meters today. Initially, laboratory


id: galvanometer-20260505-3
file: data/en.wikipedia.org/wiki/Galvanometer-3.md
category: reference
title: Galvanometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galvanometer
date_saved: 2026-05-05T09:42:36.412179+00:00
instance: kb-cron
parent: galvanometer-20260505-0
summary:
==== Geomagnetic field measurement ==== A tangent galvanometer can also be used to measure the magnitude of the horizontal component of the geomagnetic field. When used in this way, a low-voltage power source, such as a battery, is connected in series with a rheostat, the galvanometer, and an ammeter. The galvanometer is first aligned so that the coil is parallel to the geomagnetic field, whose direction is indicated by the compass when there is no current through the coils. The battery is then connected and the rheostat is adjusted until the compass needle deflects 45 degrees from the geomagnetic field, indicating that the magnitude of the magnetic field at the center of the coil is the same as that of the horizontal component of the geomagnetic field. This field strength can be calculated from the current as measured by the ammeter, the number of turns of the coil, and the radius of the coils. === Astatic galvanometer === Unlike the tangent galvanometer, the astatic galvanometer does not use the Earth's magnetic field for measurement, so it does not need to be oriented with respect to the Earth's field, making it easier to use. Developed by Leopoldo Nobili in 1825, it


id: leyden-jar-20260505-0
file: data/en.wikipedia.org/wiki/Leyden_jar-0.md
category: reference
title: Leyden jar
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Leyden_jar
date_saved: 2026-05-05T09:42:37.652328+00:00
instance: kb-cron
parent: leyden-jar-20260505-0
summary:
A Leyden jar (or Leiden jar, or archaically, Kleistian jar) is an electrical component that stores a high-voltage electric charge (from an external source) between electrical conductors on the inside and outside of a glass jar. It typically comprises a glass jar with metal foil cemented to the inside and the outside surfaces, and a metal terminal projecting vertically through the jar lid to make contact with the inner foil. It was the original form of the capacitor (also called a condenser). Its invention was a discovery made independently by German cleric Ewald Georg von Kleist on 11 October 1745 and by Dutch scientist Pieter van Musschenbroek of Leiden (Leyden), Netherlands, in 1745–1746. The Leyden jar was used to conduct many early experiments in electricity, and its discovery was of fundamental importance in the study of electrostatics. It was the first means of accumulating and preserving electric charge in large quantities that could be discharged at the experimenter's will, thus overcoming a significant limit to early research into electrical conduction. Leyden jars are still used in education to demonstrate the principles of electrostatics. == Previous work == The Ancient Greeks already knew that pieces of amber could attract lightweight particles


id: leyden-jar-20260505-1
file: data/en.wikipedia.org/wiki/Leyden_jar-1.md
category: reference
title: Leyden jar
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Leyden_jar
date_saved: 2026-05-05T09:42:37.652328+00:00
instance: kb-cron
parent: leyden-jar-20260505-0
summary:
=== Musschenbroek and Cunaeus === The Leyden jar's invention was long credited to Pieter van Musschenbroek, the physics professor at Leiden University, who also ran a family foundry which cast brass cannonettes, and a small business (De Oosterse Lamp – "The Eastern Lamp") which made scientific and medical instruments for the new university courses in physics and for scientific gentlemen keen to establish their own 'cabinets' of curiosities and instruments. Like von Kleist, Musschenbroek was also interested in, and attempting to repeat, Bose's experiment. During this time, Andreas Cunaeus, a lawyer, learned about this experiment from Musschenbroek, and attempted to duplicate the experiment at home with household items. Unaware of the "Rule of Dufay", that the experimental apparatus should be insulated, Cunaeus held his jar in his hand while charging it, and was thus the first to discover that such an experimental setup could deliver a severe shock. He reported his procedure and experience to Swiss-Dutch natural philosopher Jean-Nicolas-Sebastian Allamand, Musschenbroek's colleague. Allamand and Musschenbroek also received severe shocks. Musschenbroek communicated the experiment in a letter from 20 January 1746 to French entomologist René Antoine Ferchault de Réaumur, who was Musschenbroek's appointed correspondent at the Paris Academy. Abbé Jean-Antoine Nollet


id: leyden-jar-20260505-2
file: data/en.wikipedia.org/wiki/Leyden_jar-2.md
category: reference
title: Leyden jar
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Leyden_jar
date_saved: 2026-05-05T09:42:37.652328+00:00
instance: kb-cron
parent: leyden-jar-20260505-0
summary:
A typical design consists of a glass jar with conducting tin foil coating the inner and outer surfaces. The foil coatings stop short of the mouth of the jar, to prevent the charge from arcing between the foils. A metal rod electrode projects through the nonconductive stopper at the mouth of the jar, electrically connected by some means (usually a hanging chain) to the inner foil, to allow it to be charged. The jar is charged by an electrostatic generator, or other source of electric charge, connected to the inner electrode while the outer foil is grounded. The inner and outer surfaces of the jar store equal but opposite charges. The original form of the device is just a glass bottle partially filled with water, with a metal wire passing through a cork closing it. The role of the outer plate is provided by the hand of the experimenter. Soon John Bevis found (in 1747) that it was possible to coat the exterior of the jar with metal foil, and he also found that he could achieve the same effect by using a plate of glass with metal foil on both sides. These developments inspired William Watson in the same


id: null-detector-20260505-0
file: data/en.wikipedia.org/wiki/Null_detector-0.md
category: reference
title: Null detector
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Null_detector
date_saved: 2026-05-05T09:42:38.873146+00:00
instance: kb-cron
parent: null-detector-20260505-0
summary:
A null detectors is an electrical measurement instrument used to measure minute voltages. High precision null detectors can resolve voltage differences in the nanovolt range. Null detectors are typically designed to have high input impedance to minimize loading the circuit under test. Null detectors have historically used in calibration laboratories in conjunction with Kelvin–Varley dividers and bridge measurement circuits. Because of their sensitivity and specialized operating range, null detectors were more commonly used in laboratory than in routine field measurements. They were used as part of measurement chains that established traceability to national electrical standards, such as those maintained by National Institute of Standards and Technology (NIST). == History of Null Detectors == The development of null detectors is closely tied to the use of balance and comparison methods in electrical measurement, where the detector serves only to indicate the presence of an imbalance rather than to measure an absolute quantity. === Key stages === Galvanometers as null detectors: Early galvanometers, were commonly used as indicators of current or imbalance in circuits. In early balance and comparison arrangements, they were used to detect when two points reached equal potential, without providing calibrated measurements. Bridge circuits: The adoption of bridge circuits,


id: versorium-20260505-0
file: data/en.wikipedia.org/wiki/Versorium-0.md
category: reference
title: Versorium
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Versorium
date_saved: 2026-05-05T09:42:40.058809+00:00
instance: kb-cron
parent: versorium-20260505-0
summary:
The versorium (Latin word for "turn around") was the first electroscope, the first instrument that could detect the presence of static electric charge. It was invented in 1600 by William Gilbert, physician to Queen Elizabeth I. == Description == The versorium is a needle constructed out of metal which is allowed to pivot freely on a pedestal. It is similar to a compass needle, but unmagnetized. The needle is attracted to charged bodies brought near it, turning towards the charged object. Since it is able to distinguish between charged and non-charged objects, it is an example of a class of devices known as electroscopes. The versorium is of a similar construction to the magnetic compass, but is influenced by electrostatic rather than magnetic forces. At the time it was invented, the differences between magnetic and electrical forces were poorly understood and Gilbert did a series of experiments to prove they were two separate types of forces with the versorium and another device called a Terrella (or "little Earth"). In fact, Gilbert was the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity. == How it works == The needle turns


id: wimshurst-machine-20260505-0
file: data/en.wikipedia.org/wiki/Wimshurst_machine-0.md
category: reference
title: Wimshurst machine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wimshurst_machine
date_saved: 2026-05-05T09:42:41.290766+00:00
instance: kb-cron
parent: wimshurst-machine-20260505-0
summary:
The Wimshurst machine or Wimshurst influence machine is an electrostatic generator capable of generating high voltages. It was developed between 1880 and 1883 by British inventor James Wimshurst (1832–1903). It has a distinctive appearance with two large contra-rotating discs mounted in a vertical plane, two crossed bars with metallic brushes, and a spark gap formed by two metal spheres. == Design == These machines belong to a class of electrostatic generators called influence machines, which separate electric charges through electrostatic induction, or influence, not depending on friction for their operation. Earlier machines in this class were developed by Wilhelm Holtz (1865 and 1867), August Toepler (1865), J. Robert Voss (1880), and others. The older machines are less efficient and exhibit an unpredictable tendency to switch their polarity, while the Wimshurst machine has neither defect. In a Wimshurst machine, the two insulated discs and their metal sectors rotate in opposite directions passing the crossed metal neutralizer bars and their brushes. An imbalance of charges is induced, amplified, and collected by two pairs of brushes or metal combs with points placed near the surfaces of each disc. These collectors are mounted on insulating supports and connected to the output terminals. The positive


id: optical-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Optical_instrument-0.md
category: reference
title: Optical instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Optical_instrument
date_saved: 2026-05-05T09:42:42.800539+00:00
instance: kb-cron
parent: optical-instrument-20260505-0
summary:
An optical instrument is a device that processes light waves (or photons), either to enhance an image for viewing or to analyze and determine their characteristic properties. Common examples include periscopes, microscopes, telescopes, and cameras. == Image enhancement == The first optical instruments were telescopes used for magnification of distant images, and microscopes used for magnifying very tiny images. Since the days of Galileo and Van Leeuwenhoek, these instruments have been greatly improved and extended into other portions of the electromagnetic spectrum. The binocular device is a generally compact instrument for both eyes designed for mobile use. A camera could be considered a type of optical instrument, with the pinhole camera and camera obscura being very simple examples of such devices. == Analysis == Another class of optical instrument is used to analyze the properties of light or optical materials. They include: Interferometer for measuring the interference properties of light waves Photometer for measuring light intensity Polarimeter for measuring dispersion or rotation of polarized light Reflectometer for measuring the reflectivity of a surface or object Refractometer for measuring refractive index of various materials Spectrometer or monochromator for generating or measuring a portion of the optical spectrum, for the purpose of


id: autocollimator-20260505-0
file: data/en.wikipedia.org/wiki/Autocollimator-0.md
category: reference
title: Autocollimator
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autocollimator
date_saved: 2026-05-05T09:42:43.937135+00:00
instance: kb-cron
parent: autocollimator-20260505-0
summary:
An autocollimator is an optical instrument for non-contact measurement of angles. They are typically used to align components and measure deflections in optical or mechanical systems. An autocollimator works by projecting an image onto a target mirror and measuring the deflection of the returned image against a scale, either visually or by means of an electronic detector. A visual autocollimator can measure angles as small as 1 arcsecond (4.85 microradians), while an electronic autocollimator can have up to 100 times more resolution. Visual autocollimators are often used for aligning laser rod ends and checking the face parallelism of optical windows and wedges. Electronic and digital autocollimators are used as angle measurement standards, for monitoring angular movement over long periods of time and for checking angular position repeatability in mechanical systems. Servo autocollimators are specialized compact forms of electronic autocollimators that are used in high-speed servo-feedback loops for stable-platform applications. An electronic autocollimator is typically calibrated to read the actual mirror angle. == Electronic autocollimator == The electronic autocollimator is a high precision angle measurement instrument capable of measuring angular deviations with accuracy down to fractions of an arcsecond, by electronic means only, with no optical eye-piece. Electronic autocollimator measurement offers


id: cast-glance-20260505-0
file: data/en.wikipedia.org/wiki/Cast_Glance-0.md
category: reference
title: Cast Glance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cast_Glance
date_saved: 2026-05-05T09:42:45.118201+00:00
instance: kb-cron
parent: cast-glance-20260505-0
summary:
Cast Glance is a gyrostabilized optical instrument used by the United States Navy and United States Air Force. It is an airborne system that is used by Air Test and Evaluation Squadron 30 (VX-30) on board the Lockheed NP-3D variant of the P-3 Orion. The system consists of a moving gyro-stabilised mirror with fixed optics, two fixed cameras and five sensors. The cameras look out of the starboard side of the aircraft. The system is photometric and enables the simultaneous recording of the electro-optical to the infrared spectrum and medium wave IR. The system provides photographic coverage of air-to-air, air-to-surface or surface-to-air test operations. Cast Glance was also used to support the Space Shuttle program. == References == == External links == Cast Glance Near Infrared Imaging - Futron Corporation Video imagery produced by Cast Glance (from 02:57)


id: cathetometer-20260505-0
file: data/en.wikipedia.org/wiki/Cathetometer-0.md
category: reference
title: Cathetometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cathetometer
date_saved: 2026-05-05T09:42:46.323492+00:00
instance: kb-cron
parent: cathetometer-20260505-0
summary:
A cathetometer is an instrument for measuring vertical distances in cases where a scale cannot be placed very close to the points whose distance apart is desired. The instrument consists essentially of an accurately graduated scale and a horizontal telescope capable of being moved up and down a rigid vertical column. The position of the telescope can be read by means of an attached Vernier scale. In measuring the vertical distance between two points, the instrument must first be leveled. Next, the cross hair in the eyepiece of the horizontal telescope is brought into coincidence with the image of one point and the position of the telescope noted; the cross hair is then brought into coincidence with the image of the other point and the new position of the telescope noted. The difference between these readings is the vertical distance required. Among the uses of a cathetometer is reading the levels of a liquid in a capillary tube, such as in measurements of surface tension. A cathetometer also can be used for following the changes in liquid level in a dilatometer due to, for example, a chemical reaction therein. == See also == Travelling microscope == References ==


id: ccor-2-20260505-0
file: data/en.wikipedia.org/wiki/CCOR-2-0.md
category: reference
title: CCOR-2
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/CCOR-2
date_saved: 2026-05-05T09:43:00.904773+00:00
instance: kb-cron
parent: ccor-2-20260505-0
summary:
CCOR-2 (Compact CORonograph 2) is the second space coronograph of Compact Coronograph series and the first one in the series CCOR-1 on GOES-19. It is located aboard SOLAR-1 spacecraft (named SWFO-L1 before reaching its destination) placed at Lagrange 1 point – about 1.5 million kilometers (~930,000 miles) from the Earth towards the Sun. It will orbit the Sun at a distance between 0.974 and 1.006 AU. It was launched in September 2025 from Florida. == Mission == CCOR-2 will provide low latency, high cadence visible light (the spectrum a human eye sees) images of solar corona and its surroundings. It will observe coronal mass ejections (CME) that are potentially dangerous to electronic infrastructure and because of that its data is going to be used for space weather forecasting. CCOR coronographs are descendants of aging SOHO/LASCO and STEREO/COR instruments. It was primarily made for National Oceanic and Atmospheric Administration and Space Weather Prediction Center. === Launch and destination === It was launched aboard SpaceX Falcon 9 Rocket from Kennedy Space Flight Center located on eastern Florida at 7:30 AM EDT on 24 September 2025. It has reached L1 point on 23 January 2026 – that day its first light image was


id: cheiroscope-20260505-0
file: data/en.wikipedia.org/wiki/Cheiroscope-0.md
category: reference
title: Cheiroscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cheiroscope
date_saved: 2026-05-05T09:43:02.140168+00:00
instance: kb-cron
parent: cheiroscope-20260505-0
summary:
A cheiroscope (also: chiroscope) is an optical device consisting of a viewing instrument equipped with a drawing pad, with the viewing instrument set up as a haploscope that blends a left and/or right image into view over the drawing. The cheiroscope was presented in an article published in 1929. The author E. E. Maddox writes that compared to the earlier amblyoscope, "[t]he cheiroscope approaches the problem from a different and complementary angle, on the simple principle of pressing the hand into service to educate the eye." A cheiroscope can be operated in different manners. For example, using a cheiroscope, a line image can be presented to one eye and the image of a blank sheet to the other eye, and the subject is intended to make a drawing that reproduces the line image. The cheiroscope is used for diagnostic purposes to test binocular vision, to assess certain conditions of strabism in particular related to binocular stability and alignment, cyclotropia, and the presence and extent of suppression. It can also be used in vision therapy to train amblyopic subjects in desuppression and eye–hand coordination. A stereoscope can be modified to function as a cheiroscope. == See also == Diplopia Amblyopia Orthoptist


id: coherence-scanning-interferometry-20260505-0
file: data/en.wikipedia.org/wiki/Coherence_scanning_interferometry-0.md
category: reference
title: Coherence scanning interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Coherence_scanning_interferometry
date_saved: 2026-05-05T09:43:03.323582+00:00
instance: kb-cron
parent: coherence-scanning-interferometry-20260505-0
summary:
Coherence scanning interferometry (CSI) is any of a class of optical surface measurement methods wherein the localization of interference fringes during a scan of optical path length provides a means to determine surface characteristics such as topography, transparent film structure, and optical properties. CSI is currently the most common interference microscopy technique for areal surface topography measurement. The term "CSI" was adopted by the International Organization for Standardization (ISO). The technique encompasses but is not limited to instruments that use spectrally broadband, visible sources (white light) to achieve interference fringe localization. CSI uses either fringe localization alone or in combination with interference fringe phase, depending on the surface type, desired surface topography repeatability and software capabilities. The table below compiles alternative terms that conform at least in part to the above definition. == References ==


id: colorimeter-chemistry-20260505-0
file: data/en.wikipedia.org/wiki/Colorimeter_(chemistry)-0.md
category: reference
title: Colorimeter (chemistry)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Colorimeter_(chemistry)
date_saved: 2026-05-05T09:43:04.500380+00:00
instance: kb-cron
parent: colorimeter-chemistry-20260505-0
summary:
A colorimeter is a device used in colorimetry that measures the absorbance of particular wavelengths of light by a specific solution. It is commonly used to determine the concentration of a known solute in a given solution by the application of the Beer–Lambert law, which states that the concentration of a solute is proportional to the absorbance. == Construction == The essential parts of a colorimeter are: a light source (often an ordinary low-voltage filament lamp); an adjustable aperture; a set of colored filters; a cuvette to hold the working solution; a detector (usually a photoresistor) to measure the transmitted light; a meter to display the output from the detector. In addition, there may be: a voltage regulator, to protect the instrument from fluctuations in mains voltage; a second light path, cuvette and detector. This enables comparison between the working solution and a "blank", consisting of pure solvent, to improve accuracy. There are many commercialized colorimeters as well as open source versions with construction documentation for education and for research. === Filters === Changeable optics filters are used in the colorimeter to select the wavelength which the solute absorbs the most, in order to maximize accuracy. The usual wavelength range


id: dipleidoscope-20260505-0
file: data/en.wikipedia.org/wiki/Dipleidoscope-0.md
category: reference
title: Dipleidoscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dipleidoscope
date_saved: 2026-05-05T09:43:05.701644+00:00
instance: kb-cron
parent: dipleidoscope-20260505-0
summary:
A dipleidoscope is an instrument used to determine true noon; its name comes from the Greek for double image viewer. It consists of a small telescope and a prism that creates a double image of the sun. When the two images overlap, it is local true noon. The instrument is capable of determining true noon to within ten seconds. The dipleidoscope was invented by Giovanni Battista Amici in the first half of the 19th century. Edward John Dent, a chronometer and clockmaker in London, was working in the 1830s on a simple contrivance that would allow the public to set clocks correctly based on the transit of the sun (more complex and expensive transit telescopes had been developed by Ole Rømer in 1690). By 1840, he felt he had come to a suitable design using shadows, however when he communicated his ideas to J.M. Bloxam (a barrister), he found he had also been working on his own design using reflections, which Dent felt was superior. The two formed a partnership and worked together on the device, and after a further 2 years of work, they finalised the design and patented it (GB Patent 9793 of 1843), with Dent manufacturing and


id: disappearing-filament-pyrometer-20260505-0
file: data/en.wikipedia.org/wiki/Disappearing-filament_pyrometer-0.md
category: reference
title: Disappearing-filament pyrometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Disappearing-filament_pyrometer
date_saved: 2026-05-05T09:43:06.929588+00:00
instance: kb-cron
parent: disappearing-filament-pyrometer-20260505-0
summary:
The disappearing-filament pyrometer is an optical pyrometer, in which the temperature of a glowing incandescent object is measured by comparing it to the light of a heated filament. Invented independently in 1901 by Ludwig Holborn and Ferdinand Kurlbaum in Germany and Everett Fleet Morse in the United States, it was the first device which could measure temperatures above 1000 °C. Disappearing filament pyrometers have been used to measure temperatures between about 600 °C and 3000 °C. Like other optical pyrometers they are used to measure the temperature of objects too hot for contact thermometers, such as molten metals. Widely used in the steel and ceramics industries as well as for research, they have been almost totally superseded by electronic spectral-band pyrometers. The simplest design has optics like a Keplerian telescope. A thin wire (filament), placed at the focal plane of the objective lens, is heated by electric current. When seen through the eyepiece, the wire appears silhouetted in front of the hot luminous object under investigation. The user compares the brightness of the glowing filament with the object behind, and adjusts the current through the filament until it seems to "disappear" in front of the glowing object. At that point


id: dynameter-20260505-0
file: data/en.wikipedia.org/wiki/Dynameter-0.md
category: reference
title: Dynameter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynameter
date_saved: 2026-05-05T09:43:08.099108+00:00
instance: kb-cron
parent: dynameter-20260505-0
summary:
A dynameter is an instrument that measures the magnification of a telescope. It is usually a double-image micrometer used to measure the diameter of the image of the object glass. The magnifying power is found by comparing the actual diameter of the glass with the measured diameter of the image of the glass. == References == Dictionary entry for dynameter. The DYNAMETER, archived from the original


id: erygmascope-20260505-0
file: data/en.wikipedia.org/wiki/Erygmascope-0.md
category: reference
title: Erygmascope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Erygmascope
date_saved: 2026-05-05T09:43:09.276943+00:00
instance: kb-cron
parent: erygmascope-20260505-0
summary:
An erygmascope is a late 19th-century electric lighting apparatus designed for the examination of the strata of earth traversed by boring apparatus. It consisted of a very powerful incandescent lamp enclosed in a metallic cylinder. One of the two semi-cylindrical sides constitutes the reflector, and the other, which is of thick glass, allows the passage of light, which illuminates the strata of earth traversed by the instrument. The base, which is inclined at an angle of 45°, is an elliptical mirror, and the top, of straight section, is open in order to permit the observer standing at the mouth of the well, and provided with a powerful spyglass, to see in the mirror the image of the geological layers or of the structure of crystalline rocks. It somewhat resembles to a kind of inverted semi-periscope aimed to look at earth downwards. The lamp is so mounted that its upwardly emitted rays are intercepted. The whole apparatus was suspended from a long cable, formed of two conducting wires, which winds around a windlass with metallic journals which are electrically insulated. These journals communicate, through the intermedium of two friction springs, with the conductors on the one hand and, on the other,


id: glossmeter-20260505-0
file: data/en.wikipedia.org/wiki/Glossmeter-0.md
category: reference
title: Glossmeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossmeter
date_saved: 2026-05-05T09:43:10.484367+00:00
instance: kb-cron
parent: glossmeter-20260505-0
summary:
A glossmeter (also gloss meter) is an instrument which is used to measure specular reflection gloss of a surface. Gloss is determined by projecting a beam of light at a fixed intensity and angle onto a surface and measuring the amount of reflected light at an equal but opposite angle. There are a number of different geometries available for gloss measurement, each being dependent on the type of surface to be measured. For non-metals such as coatings and plastics the amount of reflected light increases with a greater angle of illumination, as some of the light penetrates the surface material and is absorbed into it or diffusely scattered from it depending on its colour. Metals have a much higher reflection and are therefore less angularly dependent. Many international technical standards are available that define the method of use and specifications for different types of glossmeter used on various types of materials including paint, ceramics, paper, metals and plastics. Many industries use glossmeters in their quality control to measure the gloss of products to ensure consistency in their manufacturing processes. The automotive industry is a major user of the glossmeter, with applications extending from the factory floor to the repair shop.


id: glossmeter-20260505-1
file: data/en.wikipedia.org/wiki/Glossmeter-1.md
category: reference
title: Glossmeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glossmeter
date_saved: 2026-05-05T09:43:10.484367+00:00
instance: kb-cron
parent: glossmeter-20260505-0
summary:
For example, if the measurement made at 60° is greater than 70 GU, the measurement angle should be changed to 20° to optimise measurement accuracy. Three types of instruments are available on the market: 60° single angle instruments, a combination of 20° and 60° and one type that combines 20°, 60° and 85°. Two additional angles are used for other materials. An angle of 45° is specified for the measurement of ceramics, films, textiles and anodised aluminium, whilst 75° is specified for paper and printed materials. == Gloss units == The measurement scale, gloss units (GU), of a glossmeter is a scaling based on a highly polished reference black glass standard with a defined refractive index having a specular reflectance of 100GU at the specified angle. This standard is used to establish an upper point calibration of 100 with the lower end point established at 0 on a perfectly matte surface. This scaling is suitable for most non-metallic coatings and materials (paints and plastics) as they generally fall within this range. For other materials, highly reflective in appearance (mirrors, plated / raw metal components), higher values can be achieved reaching 2000 Gloss Units. For transparent materials, these values can also


id: haze-meter-20260505-0
file: data/en.wikipedia.org/wiki/Haze_meter-0.md
category: reference
title: Haze meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haze_meter
date_saved: 2026-05-05T09:43:11.625842+00:00
instance: kb-cron
parent: haze-meter-20260505-0
summary:
A haze meter measures the amount of light that is diffused or scattered when passing through a transparent material. Transparency is important because a material needs to be more or less see-through depending on its practical usage, e.g. a grocery bag needs the light to be more diffused so that less can be seen while food packaging film needs the light to be less diffused so that the contents can be seen clearly. For reasons such as these haze meters are necessary to determine which material is needed for which practical purpose. Haze is measured with a wide angle scattering test in which light is diffused in all directions which results in a loss of contrast. That percentage of light that when passing through that deviates from the incident beam by greater than 2.5 degrees on average is defined as haze See through quality is measured with a narrow angle scattering test in which light is diffused in a small range with high concentration. This test measures the clarity with which finer details can be seen through the object being tested. The haze meter also measures total transmittance. Total transmittance is the measure of the total incident light compared to


id: hilger-watts-20260505-0
file: data/en.wikipedia.org/wiki/Hilger_&_Watts-0.md
category: reference
title: Hilger & Watts
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hilger_&_Watts
date_saved: 2026-05-05T09:43:12.767255+00:00
instance: kb-cron
parent: hilger-watts-20260505-0
summary:
Hilger & Watts was a well-known British manufacturing company that made theodolites and scientific instruments. == History == It was founded on 20 February 1948 when Adam Hilger, Ltd, founded in 1874, merged with Messrs E. R. Watts and Son by Edwin Richard Watts (1833–1901) and George William Watts (c. 1871–1954), founded in 1865. The company was taken over by the Rank Organisation in 1969 and later sold on. == Structure == It employed around 1,300 people in six factories in the late 1940s. It was situated on Camberwell Road (A215 road) in Camberwell, near the junction with the B214, between Walworth (to the north) and Camberwell (to the south) on the western edge of Burgess Park, now part of the London Borough of Southwark. There was a factory in Highbury, together with the head office in Camden Town and a small factory situated between Margate and Ramsgate in Kent. These locations were primarily "Hilger" products, whereas Camberwell was primarily Watts products. The company also had a factory at Loughton (Debden) in Essex == Products == Optical instruments Photometers Theodolite and surveying equipment Tripods Computer controlled X-ray diffractometers Amongst other devices, the Camden location produced PDP-8 computer-driven X-ray diffractometers in


id: hydroscope-20260505-0
file: data/en.wikipedia.org/wiki/Hydroscope-0.md
category: reference
title: Hydroscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hydroscope
date_saved: 2026-05-05T09:43:13.924162+00:00
instance: kb-cron
parent: hydroscope-20260505-0
summary:
A hydroscope is any of several instruments related to water: One kind is an instrument for making observations below the surface of water, such as a long tube fitted with various lenses arranged so that objects lying at the bottom can be reflected upon a screen on the deck of the ship that carries it. These are built with a large tire tube that supports the screen and covered by an acrylic dome for protection. Another kind detects subsurface water through nuclear magnetic resonance using the surface nuclear magnetic resonance technique. An instrument (likely a hydrometer) described by Synesius in his Letter 15 to Hypatia, written in 402 AD. There are references to such instruments as early as the fourth century. Another ancient Greek instrument: a water clock or clepsydra. == Sources and notes ==


id: interferometry-20260505-0
file: data/en.wikipedia.org/wiki/Interferometry-0.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
Interferometry is a technique which uses the interference of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber optics, engineering metrology, optical metrology, oceanography, seismology, spectroscopy (and its applications to chemistry), quantum mechanics, nuclear and particle physics, plasma physics, biomolecular interactions, surface profiling, microfluidics, mechanical stress/strain measurement, velocimetry, optometry, and making holograms. Interferometers are devices that extract information from interference. They are widely used in science and industry for the measurement of microscopic displacements, refractive index changes and surface irregularities. In the case with most interferometers, light from a single source is split into two beams that travel in different optical paths, which are then combined again to produce interference; two incoherent sources can also be made to interfere under some circumstances. The resulting interference fringes give information about the difference in optical path lengths. In analytical science, interferometers are used to measure lengths and the shape of optical components with nanometer precision; they are the highest-precision length measuring instruments in existence. In Fourier transform spectroscopy they are used to analyze light containing features of absorption or emission associated with a substance or mixture. An astronomical interferometer


id: interferometry-20260505-1
file: data/en.wikipedia.org/wiki/Interferometry-1.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
== History == The law of interference of light was described by Thomas Young in his 1803 Bakerian Lecture to the Royal Society of London. In preparation for the lecture, Young performed a double-aperture experiment in a water ripple tank. His interpretation in terms of the interference of waves was rejected by most scientists at the time because of the dominance of Isaac Newton's corpuscular theory of light proposed a century before. The French engineer Augustin-Jean Fresnel, unaware of Young's results, began working on a wave theory of light and interference and was introduced to François Arago. Between 1816 and 1818, Fresnel and Arago performed interference experiments at the Paris Observatory. During this time, Arago designed and built the first interferometer, using it to measure the refractive index of moist air relative to dry air, which posed a potential problem for astronomical observations of star positions. The success of Fresnel's wave theory of light was established in his prize-winning memoire of 1819 that predicted and measured diffraction patterns. The Arago interferometer was later employed in 1850 by Leon Foucault to measure the speed of light in air relative to water, and it was used again in 1851 by Hippolyte Fizeau


id: interferometry-20260505-2
file: data/en.wikipedia.org/wiki/Interferometry-2.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
In 1803, Young's interference experiment played a major role in the general acceptance of the wave theory of light. If white light is used in Young's experiment, the result is a white central band of constructive interference corresponding to equal path length from the two slits, surrounded by a symmetrical pattern of colored fringes of diminishing intensity. In addition to continuous electromagnetic radiation, Young's experiment has been performed with individual photons, with electrons, and with buckyball molecules large enough to be seen under an electron microscope. Lloyd's mirror generates interference fringes by combining direct light from a source (blue lines) and light from the source's reflected image (red lines) from a mirror held at grazing incidence. The result is an asymmetrical pattern of fringes. The band of equal path length, nearest the mirror, is dark rather than bright. In 1834, Humphrey Lloyd interpreted this effect as proof that the phase of a front-surface reflected beam is inverted. ==== Amplitude-splitting inferometers ==== An amplitude splitting interferometer uses a partial reflector to divide the amplitude of the incident wave into separate beams which are separated and recombined. The Fizeau interferometer is shown as it might be set up to test an optical


id: interferometry-20260505-3
file: data/en.wikipedia.org/wiki/Interferometry-3.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
In physics, one of the most important experiments of the late 19th century was the famous "failed experiment" of Michelson and Morley which provided evidence for special relativity. Recent repetitions of the Michelson–Morley experiment perform heterodyne measurements of beat frequencies of crossed cryogenic optical resonators. Fig 7 illustrates a resonator experiment performed by Müller et al. in 2003. Two optical resonators constructed from crystalline sapphire, controlling the frequencies of two lasers, were set at right angles within a helium cryostat. A frequency comparator measured the beat frequency of the combined outputs of the two resonators. As of 2009, the precision by which anisotropy of the speed of light can be excluded in resonator experiments is at the 10−17 level. Michelson interferometers are used in tunable narrow band optical filters and as the core hardware component of Fourier transform spectrometers. When used as a tunable narrow band filter, Michelson interferometers exhibit a number of advantages and disadvantages when compared with competing technologies such as Fabry–Pérot interferometers or Lyot filters. Michelson interferometers have the largest field of view for a specified wavelength, and are relatively simple in operation, since tuning is via mechanical rotation of waveplates rather than via high voltage control


id: interferometry-20260505-4
file: data/en.wikipedia.org/wiki/Interferometry-4.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
Astronomical optical interferometry has had to overcome a number of technical issues not shared by radio telescope interferometry. The short wavelengths of light necessitate extreme precision and stability of construction. For example, spatial resolution of 1 milliarcsecond requires 0.5 μm stability in a 100 m baseline. Optical interferometric measurements require high sensitivity, low noise detectors that did not become available until the late 1990s. Astronomical "seeing", the turbulence that causes stars to twinkle, introduces rapid, random phase changes in the incoming light, requiring data collection rates to be faster than the rate of turbulence. Despite these technical difficulties, three major facilities are now in operation offering resolutions down to the fractional milliarcsecond range. The wave character of matter can be exploited to build interferometers. The first examples of matter interferometers were electron interferometers, later followed by neutron interferometers. Around 1990 the first atom interferometers were demonstrated, later followed by interferometers employing molecules. Electron holography is an imaging technique that photographically records the electron interference pattern of an object, which is then reconstructed to yield a greatly magnified image of the original object. This technique was developed to enable greater resolution in electron microscopy than is possible using conventional imaging techniques.


id: interferometry-20260505-5
file: data/en.wikipedia.org/wiki/Interferometry-5.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
The Twyman–Green interferometer, invented by Twyman and Green in 1916, is a variant of the Michelson interferometer widely used to test optical components. The basic characteristics distinguishing it from the Michelson configuration are the use of a monochromatic point light source and a collimator. Michelson (1918) criticized the Twyman–Green configuration as being unsuitable for the testing of large optical components, since the light sources available at the time had limited coherence length. Michelson pointed out that constraints on geometry forced by limited coherence length required the use of a reference mirror of equal size to the test mirror, making the Twyman–Green impractical for many purposes. Decades later, the advent of laser light sources answered Michelson's objections. (A Twyman–Green interferometer using a laser light source and unequal path length is known as a Laser Unequal Path Interferometer, or LUPI.) Fig. 14 illustrates a Twyman–Green interferometer set up to test a lens. Light from a monochromatic point source is expanded by a diverging lens (not shown), then is collimated into a parallel beam. A convex spherical mirror is positioned so that its center of curvature coincides with the focus of the lens being tested. The emergent beam is recorded by an imaging


id: interferometry-20260505-6
file: data/en.wikipedia.org/wiki/Interferometry-6.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
Optical heterodyne detection is an essential technique used in high-accuracy measurements of the frequencies of optical sources, as well as in the stabilization of their frequencies. Until relatively few years ago, lengthy frequency chains were needed to connect the microwave frequency of a cesium or other atomic time source to optical frequencies. At each step of the chain, a frequency multiplier would be used to produce a harmonic of the frequency of that step, which would be compared by heterodyne detection with the next step (the output of a microwave source, far infrared laser, infrared laser, or visible laser). Each measurement of a single spectral line required several years of effort in the construction of a custom frequency chain. Currently, optical frequency combs have provided a much simpler method of measuring optical frequencies. If a mode-locked laser is modulated to form a train of pulses, its spectrum is seen to consist of the carrier frequency surrounded by a closely spaced comb of optical sideband frequencies with a spacing equal to the pulse repetition frequency (Fig. 16). The pulse repetition frequency is locked to that of the frequency standard, and the frequencies of the comb elements at the red end of


id: interferometry-20260505-7
file: data/en.wikipedia.org/wiki/Interferometry-7.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
In coherence scanning interferometry, interference is only achieved when the path length delays of the interferometer are matched within the coherence time of the light source. CSI monitors the fringe contrast rather than the phase of the fringes. Fig. 17 illustrates a CSI microscope using a Mirau interferometer in the objective; other forms of interferometer used with white light include the Michelson interferometer (for low magnification objectives, where the reference mirror in a Mirau objective would interrupt too much of the aperture) and the Linnik interferometer (for high magnification objectives with limited working distance). The sample (or alternatively, the objective) is moved vertically over the full height range of the sample, and the position of maximum fringe contrast is found for each pixel. The chief benefit of coherence scanning interferometry is that systems can be designed that do not suffer from the 2 pi ambiguity of coherent interferometry, and as seen in Fig. 18, which scans a 180μm x 140μm x 10μm volume, it is well suited to profiling steps and rough surfaces. The axial resolution of the system is determined in part by the coherence length of the light source. Industrial applications include in-process surface metrology, roughness measurement, 3D


id: interferometry-20260505-8
file: data/en.wikipedia.org/wiki/Interferometry-8.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
Interferometric synthetic aperture radar (InSAR) is a radar technique used in geodesy and remote sensing. Satellite synthetic aperture radar images of a geographic feature are taken on separate days, and changes that have taken place between radar images taken on the separate days are recorded as fringes similar to those obtained in holographic interferometry. The technique can monitor centimeter- to millimeter-scale deformation resulting from earthquakes, volcanoes and landslides, and also has uses in structural engineering, in particular for the monitoring of subsidence and structural stability. Fig 20 shows Kilauea, an active volcano in Hawaii. Data acquired using the space shuttle Endeavour's X-band Synthetic Aperture Radar on April 13, 1994 and October 4, 1994 were used to generate interferometric fringes, which were overlaid on the X-SAR image of Kilauea. Electronic speckle pattern interferometry (ESPI), also known as TV holography, uses video detection and recording to produce an image of the object upon which is superimposed a fringe pattern which represents the displacement of the object between recordings. (see Fig. 21) The fringes are similar to those obtained in holographic interferometry. When lasers were first invented, laser speckle was considered to be a severe drawback in using lasers to illuminate objects, particularly


id: interferometry-20260505-9
file: data/en.wikipedia.org/wiki/Interferometry-9.md
category: reference
title: Interferometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interferometry
date_saved: 2026-05-05T09:43:15.174742+00:00
instance: kb-cron
parent: interferometry-20260505-0
summary:
Phase contrast and differential interference contrast (DIC) microscopy are important tools in biology and medicine. Most animal cells and single-celled organisms have very little color, and their intracellular organelles are almost totally invisible under simple bright field illumination. These structures can be made visible by staining the specimens, but staining procedures are time-consuming and kill the cells. As seen in Figs. 24 and 25, phase contrast and DIC microscopes allow unstained, living cells to be studied. DIC also has non-biological applications, for example in the analysis of planar silicon semiconductor processing. Angle-resolved low-coherence interferometry (a/LCI) uses scattered light to measure the sizes of subcellular objects, including cell nuclei. This allows interferometry depth measurements to be combined with density measurements. Various correlations have been found between the state of tissue health and the measurements of subcellular objects. For example, it has been found that as tissue changes from normal to cancerous, the average cell nuclei size increases. Phase-contrast X-ray imaging (Fig. 26) refers to a variety of techniques that use phase information of a coherent x-ray beam to image soft tissues. (For an elementary discussion, see Phase-contrast x-ray imaging (introduction). For a more in-depth review, see Phase-contrast X-ray imaging.) It has


id: level-optical-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Level_(optical_instrument)-0.md
category: reference
title: Level (optical instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Level_(optical_instrument)
date_saved: 2026-05-05T09:43:16.386089+00:00
instance: kb-cron
parent: level-optical-instrument-20260505-0
summary:
A level is an optical instrument used to establish or verify points in the same horizontal plane in a process known as levelling. It is used in conjunction with a levelling staff to establish the relative height or levels (the vertical separation) of objects or marks. It is widely used in surveying and construction to measure height differences and to transfer, measure, and set heights of known objects or marks. It is also known as a surveyor's level, builder's level, dumpy level or the historic "Y level". It operates on the principle of establishing a visual level relationship between two or more points, for which an inbuilt optical telescope and a highly accurate bubble level are used to achieve the necessary accuracy. Traditionally the instrument was completely adjusted manually to ensure a level line of sight, but modern automatic versions self-compensate for slight errors in the coarse levelling of the instrument, and are thereby quicker to use. The optical level should not be confused with a theodolite, which can also measure angles in the vertical plane. == Description == The complete unit is normally mounted on a tripod, and the telescope can freely rotate 360° in a horizontal plane. The


id: level-optical-instrument-20260505-1
file: data/en.wikipedia.org/wiki/Level_(optical_instrument)-1.md
category: reference
title: Level (optical instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Level_(optical_instrument)
date_saved: 2026-05-05T09:43:16.386089+00:00
instance: kb-cron
parent: level-optical-instrument-20260505-0
summary:
An automatic level, self-levelling level, or builder's auto level includes an internal compensator mechanism (a swinging prism) that, when set close to level, automatically removes any remaining variation. This reduces the need to set the instrument base truly level, as with a dumpy level. Self-levelling instruments are the preferred instrument on building sites, construction, and during surveying due to ease of use and rapid setup time. The world's first automatic level was introduced on 8 March 1950. It was produced by the German company Zeiss-Opton in Oberkochen. Main components of an automatic level include a tribrach – a lower, fixed, triangular or circular element containing three sockets for adjusting screws (or wedge rings), attached to the tripod with a heart screw – and an alidade – a movable (rotatable) part. In automatic levels, the spirit level is most often replaced by a pendulum-based opto-mechanical device called a compensator. === Digital electronic level === A digital electronic level is also set level on a tripod and reads a bar-coded staff using electronic laser methods. The height of the staff where the level beam crosses the staff is shown on a digital display. This type of level removes interpolation of graduation by


id: list-of-viewing-instruments-20260505-0
file: data/en.wikipedia.org/wiki/List_of_viewing_instruments-0.md
category: reference
title: List of viewing instruments
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_viewing_instruments
date_saved: 2026-05-05T09:43:17.548748+00:00
instance: kb-cron
parent: list-of-viewing-instruments-20260505-0
summary:
A viewing instrument is a type of optical instrument that is used to assist viewing or visually examining an object or scenery. == Types == == References ==


id: lovibond-comparator-20260505-0
file: data/en.wikipedia.org/wiki/Lovibond_comparator-0.md
category: reference
title: Lovibond comparator
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Lovibond_comparator
date_saved: 2026-05-05T09:43:18.709605+00:00
instance: kb-cron
parent: lovibond-comparator-20260505-0
summary:
The Lovibond comparator is an example of a colorimeter made in Britain by The Tintometer Ltd. It was invented in the 19th century by Joseph Williams Lovibond, a British brewer and chemist, as a tool to standardize the production of beer. Updated versions are still available. == Description == The device is used to determine the color of liquids. A sample is put in a glass tube. The tube is inserted in the comparator and compared with a series of colored glass discs until the nearest possible match is found. Among other things, the device is used to determine the concentration of certain chemicals in solution. In this use, some assumptions are made about what is in the sample. Given those assumptions, the concentration will be indicated by the disc which best matches the color of the solution. There are a number of standard tests in which a sample to be tested is mixed with a color reagent. In such tests, the resulting color indicates the concentration of the sample under test (see Beer–Lambert law). Results can be approximate, compared to other testing techniques, but the comparator is useful for field work because it is portable, rugged and easy to


id: mirror-galvanometer-20260505-0
file: data/en.wikipedia.org/wiki/Mirror_galvanometer-0.md
category: reference
title: Mirror galvanometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mirror_galvanometer
date_saved: 2026-05-05T09:43:19.898895+00:00
instance: kb-cron
parent: mirror-galvanometer-20260505-0
summary:
A mirror galvanometer is an ammeter that indicates it has sensed an electric current by deflecting a light beam with a mirror. The beam of light projected on a scale acts as a long massless pointer. In 1826, Johann Christian Poggendorff developed the mirror galvanometer for detecting electric currents. The apparatus is also known as a spot galvanometer after the spot of light produced in some models. Mirror galvanometers were used extensively in scientific instruments before reliable, stable electronic amplifiers were available. The most common uses were as recording equipment for seismometers and submarine cables used for telegraphy. In modern times, the term mirror galvanometer is also used for devices that move laser beams by rotating a mirror through a galvanometer set-up, often with a servo-like control loop. The name is often abbreviated as galvo. == Kelvin's galvanometer == The mirror galvanometer was improved significantly by William Thomson, later to become Lord Kelvin. He coined the term mirror galvanometer and patented the device in 1858. Thomson intended the instrument to read weak signal currents on very long submarine telegraph cables. This instrument was far more sensitive than any which preceded it, enabling the detection of the slightest defect in the


id: mirror-galvanometer-20260505-1
file: data/en.wikipedia.org/wiki/Mirror_galvanometer-1.md
category: reference
title: Mirror galvanometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mirror_galvanometer
date_saved: 2026-05-05T09:43:19.898895+00:00
instance: kb-cron
parent: mirror-galvanometer-20260505-0
summary:
Moving coil galvanometer was developed independently by Marcel Deprez and Jacques-Arsène d'Arsonval about 1880. Deprez's galvanometer was developed for high currents, while D'Arsonval designed his to measure weak currents. Unlike in the Kelvin's galvanometer, in this type of galvanometer the magnet is stationary and the coil is suspended in the magnet gap. The mirror attached to the coil frame rotates together with it. This form of instrument can be more sensitive and accurate and it replaced the Kelvin's galvanometer in most applications. The moving coil galvanometer is practically immune to ambient magnetic fields. Another important feature is self-damping generated by the electro-magnetic forces due to the currents induced in the coil by its movements the magnetic field. These are proportional to the angular velocity of the coil. == Modern uses == In modern times, high-speed mirror galvanometers are employed in laser light shows to move the laser beams and produce colorful geometric patterns in fog around the audience. Such high speed mirror galvanometers have proved to be indispensable in industry for laser marking systems for everything from laser etching hand tools, containers, and parts to batch-coding semiconductor wafers in semiconductor device fabrication. They typically control X and Y directions on


id: n-slit-interferometer-20260505-0
file: data/en.wikipedia.org/wiki/N-slit_interferometer-0.md
category: reference
title: N-slit interferometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/N-slit_interferometer
date_saved: 2026-05-05T09:43:21.075248+00:00
instance: kb-cron
parent: n-slit-interferometer-20260505-0
summary:
The N-slit interferometer is an extension of the double-slit interferometer also known as Young's double-slit interferometer. One of the first known uses of N-slit arrays in optics was illustrated by Newton. In the first part of the twentieth century, Michelson described various cases of N-slit diffraction. Feynman described thought experiments the explored two-slit quantum interference of electrons, using Dirac's notation. This approach was extended to N-slit interferometers, by Duarte and colleagues in 1989, using narrow-linewidth laser illumination, that is, illumination by indistinguishable photons. The first application of the N-slit interferometer was the generation and measurement of complex interference patterns. These interferograms are accurately reproduced, or predicted, by the N-slit interferometric equation for either even (N = 2, 4, 6,...), or odd (N = 3, 5, 7,...), numbers of slits. == N-slit laser interferometer == The N-slit laser interferometer, introduced by Duarte, uses prismatic beam expansion to illuminate a transmission grating, or N-slit array, and a photoelectric detector array (such as a CCD or CMOS) at the interference plane to register the interferometric signal. The expanded laser beam illuminating the N-slit array is single-transverse-mode and narrow-linewidth. This beam can also take the shape, via the introduction of a convex lens prior


id: optical-correlator-20260505-0
file: data/en.wikipedia.org/wiki/Optical_correlator-0.md
category: reference
title: Optical correlator
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Optical_correlator
date_saved: 2026-05-05T09:43:22.231203+00:00
instance: kb-cron
parent: optical-correlator-20260505-0
summary:
An optical correlator is an optical computer for comparing two signals by utilising the Fourier transforming properties of a lens. It is commonly used in optics for target tracking and identification. == Introduction == The correlator has an input signal which is multiplied by some filter in the Fourier domain. An example filter is the matched filter which uses the cross correlation of the two signals. The cross correlation or correlation plane, c ( x , y ) {\displaystyle c(x,y)} of a 2D signal i ( x , y ) {\displaystyle i(x,y)} with h ( x , y ) {\displaystyle h(x,y)} is c ( x , y ) = i ( x , y ) ⊗ h ∗ ( − x , − y ) {\displaystyle c(x,y)=i(x,y)\otimes h^{*}(-x,-y)} This can be re-expressed in Fourier space as C ( ξ , η ) = I ( ξ , η ) H ∗ ( − ξ , − η ) {\displaystyle C(\xi ,\eta )=I(\xi ,\eta )H^{*}(-\xi ,-\eta )} where the capital letters denote the Fourier transform of what the lower case letter denotes. So the correlation can then be calculated by inverse Fourier transforming the result. == Implementation == According to Fresnel


id: optical-power-meter-20260505-0
file: data/en.wikipedia.org/wiki/Optical_power_meter-0.md
category: reference
title: Optical power meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Optical_power_meter
date_saved: 2026-05-05T09:43:23.426777+00:00
instance: kb-cron
parent: optical-power-meter-20260505-0
summary:
An optical power meter (OPM) is a device used to measure the power in an optical signal. The term usually refers to a device for testing average power in fiber optic systems. Other general purpose light power measuring devices are usually called radiometers, photometers, laser power meters (can be photodiode sensors or thermopile laser sensors), light meters or lux meters. A typical optical power meter consists of a calibrated sensor, measuring amplifier and display. The sensor primarily consists of a photodiode selected for the appropriate range of wavelengths and power levels. On the display unit, the measured optical power and set wavelength is displayed. Power meters are calibrated using a traceable calibration standard. A traditional optical power meter responds to a broad spectrum of light, however, the calibration is wavelength dependent. This is not normally an issue, since the test wavelength is usually known, however, it has a couple of drawbacks. Firstly, the user must set the meter to the correct test wavelength, and secondly, if there are other spurious wavelengths present, then wrong readings will result. Optical power meters are available as stand-alone bench or handheld instruments or combined with other test functions such as an Optical Light Source


id: optical-power-meter-20260505-1
file: data/en.wikipedia.org/wiki/Optical_power_meter-1.md
category: reference
title: Optical power meter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Optical_power_meter
date_saved: 2026-05-05T09:43:23.426777+00:00
instance: kb-cron
parent: optical-power-meter-20260505-0
summary:
== Calibration and accuracy == Optical Power Meter calibration and accuracy is a contentious issue. The accuracy of most primary reference standards (e.g. Weight, Time, Length, Volt, etc.) is known to a high accuracy, typically of the order of 1 part in a billion. However the optical power standards maintained by various National Standards Laboratories, are only defined to about one part in a thousand. By the time this accuracy has been further degraded through successive links, instrument calibration accuracy is usually only a few %. The most accurate field optical power meters claim 1% calibration accuracy. This is orders of magnitude less accurate than a comparable electrical meter. Calibration processes for optical power meters are given in IEC 61315 Ed. 3.0 b:2019 - Calibration of fibre-optic power meters. Furthermore, the in-use accuracy achieved is usually significantly lower than the claimed calibration accuracy, by the time additional factors are taken into account. In typical field applications, factors may include: ambient temperature, optical connector type, wavelength variations, linearity variations, beam geometry variations, detector saturation. Therefore, achieving a good level of practical instrument accuracy and linearity is something that requires design skill, and high manufacturing proficiency. With the increasing global importance in


id: perspective-machine-20260505-0
file: data/en.wikipedia.org/wiki/Perspective_machine-0.md
category: reference
title: Perspective machine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Perspective_machine
date_saved: 2026-05-05T09:43:24.616799+00:00
instance: kb-cron
parent: perspective-machine-20260505-0
summary:
A perspective machine is an optical instrument designed to help artists create perspective drawings. The earliest machines were built centuries ago when the theory of perspective was being worked out, and modern versions are still in use. == Timeline == 1510: Leonardo da Vinci's Draftsman drawing an armillary sphere shows an early form of perspective machine in use. 1525: Albrecht Dürer, in his illustration Man drawing a lute, shows an artist using a perspective machine to create a drawing. The machine consists of a wooden frame with a taut string passing through it to represent the viewer's line of sight. Dürer built his second model of such a machine in the same year. c.1765: Scottish engineer James Watt designs a machine based on an easel, with a pantograph mechanism allowing the artist to trace an object using a sight arm and transfer the movement of the sight to a pen drawing on paper. Watt stated that his machine was based on an invention by a Mr Hurst, who lived in India. 1763: Philosopher Thomas Reid uses a machine to investigate his theory of perception. 1825: English inventor Francis Ronalds patents two perspective tracing machines. One generated an accurate drawing of


id: photometer-20260505-0
file: data/en.wikipedia.org/wiki/Photometer-0.md
category: reference
title: Photometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photometer
date_saved: 2026-05-05T09:43:26.920738+00:00
instance: kb-cron
parent: photometer-20260505-0
summary:
A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance, or luminance. Historically, photometry was done by estimation, comparing the luminous flux of a source with a standard source. By the 19th century, common photometers included Rumford's photometer, which compared the depths of shadows cast by different light sources, and Ritchie's photometer, which relied on equal illumination of surfaces. Another type was based on the extinction of shadows. Most modern photometers detect light by converting it into an electric current using a photoresistor, photodiode, or photomultiplier. Some models employ photon counting, measuring light by counting individual photons. They are especially useful in areas where the irradiance is low. Photometers have wide-ranging applications including photography, where they determine the correct exposure, and science, where they are used in absorption spectroscopy to calculate the concentration of substances in a solution, infrared spectroscopy to study the structure of substances, and atomic absorption spectroscopy to determine the concentration of metals in a solution. == History == Before electronic light sensitive elements were developed, photometry was done by estimation by the eye. The relative luminous flux of a source was compared with a standard source. The photometer is placed such that


id: photometer-20260505-1
file: data/en.wikipedia.org/wiki/Photometer-1.md
category: reference
title: Photometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photometer
date_saved: 2026-05-05T09:43:26.920738+00:00
instance: kb-cron
parent: photometer-20260505-0
summary:
== Visible light reflectance photometry == A reflectance photometer measures the reflectance of a surface as a function of wavelength. The surface is illuminated with white light, and the reflected light is measured after passing through a monochromator. This type of measurement has mainly practical applications, for instance in the paint industry to characterize the colour of a surface objectively. == UV and visible light transmission photometry == These are optical instruments for measurement of the absorption of light of a given wavelength (or a given range of wavelengths) of coloured substances in solution. From the light absorption, Beer's law makes it possible to calculate the concentration of the coloured substance in the solution. Due to its wide range of application and its reliability and robustness, the photometer has become one of the principal instruments in biochemistry and analytical chemistry. Absorption photometers for work in aqueous solution work in the ultraviolet and visible ranges, from wavelength around 240 nm up to 750 nm. The principle of spectrophotometers and filter photometers is that (as far as possible) monochromatic light is allowed to pass through a container (cell) with optically flat windows containing the solution. It then reaches a light detector, that


id: polarimeter-20260505-0
file: data/en.wikipedia.org/wiki/Polarimeter-0.md
category: reference
title: Polarimeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Polarimeter
date_saved: 2026-05-05T09:43:28.106070+00:00
instance: kb-cron
parent: polarimeter-20260505-0
summary:
A polarimeter is a scientific instrument used to measure optical rotation: the angle of rotation caused by passing linearly polarized light through an optically active substance. Some chemical substances are optically active, and linearly polarized (uni-directional) light will rotate either to the left (counter-clockwise) or right (clockwise) when passed through these substances. The amount by which the light is rotated is known as the angle of rotation. The direction (clockwise or counterclockwise) and magnitude of the rotation reveals information about the sample's chiral properties such as the relative concentration of enantiomers present in the sample. == History == Polarization by reflection was discovered in 1808 by Étienne-Louis Malus (1775–1812). == Measuring principle == The ratio, the purity, and the concentration of two enantiomers can be measured via polarimetry. Enantiomers are characterized by their property to rotate the plane of linear polarized light. Therefore, those compounds are called optically active and their property is referred to as optical rotation. Light sources such as a light bulb, Tungsten Halogen, or the sun emit electromagnetic waves at the frequency of visible light. Their electric field oscillates in all possible planes relative to their direction of propagation. In contrast to that, the waves of


id: polarimeter-20260505-1
file: data/en.wikipedia.org/wiki/Polarimeter-1.md
category: reference
title: Polarimeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Polarimeter
date_saved: 2026-05-05T09:43:28.106070+00:00
instance: kb-cron
parent: polarimeter-20260505-0
summary:
=== Laurent's half-shade polarimeter === When plane-polarised light passes through some crystals, the velocity of left-polarized light is different from that of the right-polarized light, thus the crystals are said to have two refractive indices, i.e. double refracting. Construction: The polarimeter consists of a monochromatic source S which is placed at focal point of a convex lens L. Just after the convex lens there is a Nicol Prism P which acts as a polariser. H is a half shade device which divides the field of polarized light emerging out of the Nicol P into two halves, generally of unequal brightness. T is a glass tube in which an optically active solution is filled. The light, after passing through T, is allowed to fall on the analyzing Nicol A which can be rotated about the axis of the tube. The rotation of the analyzer can be measured with the help of a scale C. Working principle: To understand the need of a half-shade device, let us suppose that it is not present. The position of the analyzer is adjusted so that the field of view is dark when the tube is empty. The position of the analyzer is noted on the


id: polarimeter-20260505-2
file: data/en.wikipedia.org/wiki/Polarimeter-2.md
category: reference
title: Polarimeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Polarimeter
date_saved: 2026-05-05T09:43:28.106070+00:00
instance: kb-cron
parent: polarimeter-20260505-0
summary:
=== Manual === The earliest polarimeters, which date back to the 1830s, required the user to physically rotate one polarizing element (the analyzer) whilst viewing through another static element (the detector). The detector was positioned at the opposite end of a tube containing the optically active sample, and the user used his/her eye to judge the "alignment" when least light was observed. The angle of rotation was then read from a simple fixed to the moving polariser to within a degree or so. Although most manual polarimeters produced today still adopt this basic principle, the many developments applied to the original opto-mechanical design over the years have significantly improved measurement performance. The introduction of a half-wave plate increased "distinction sensitivity", whilst a precision glass scale with vernier drum facilitated the final reading to within ca. ±0.05º. Most modern manual polarimeters also incorporate a long-life yellow LED in place of the more costly sodium arc lamp as a light source. === Semi-automatic === Today, semi-automatic polarimeters are available. The operator views the image via a digital display adjusts the analyzer angle with electronic controls. === Fully automatic === Fully automatic polarimeters are now widely used and simply require the user to


id: polarimeter-20260505-3
file: data/en.wikipedia.org/wiki/Polarimeter-3.md
category: reference
title: Polarimeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Polarimeter
date_saved: 2026-05-05T09:43:28.106070+00:00
instance: kb-cron
parent: polarimeter-20260505-0
summary:
=== Chemical industry === Many chemicals exhibit a specific rotation as a unique property (an intensive property like refractive index or specific gravity) which can be used to distinguish it. Polarimeters can identify unknown samples based on this if other variables such as concentration and length of sample cell length are controlled or at least known. This is used in the chemical industry. By the same token, if the specific rotation of a sample is already known, then the concentration and/or purity of a solution containing it can be calculated. Most automatic polarimeters make this calculation automatically, given input on variables from the user. === Food, beverage and pharmaceutical industries === Concentration and purity measurements are especially important to determine product or ingredient quality in the food & beverage and pharmaceutical industries. Samples that display specific rotations that can be calculated for purity with a polarimeter include: Polarimeters are used in the sugar industry for determining quality of both juice from sugar cane and the refined sucrose. Often, the sugar refineries use a modified polarimeter with a flow cell (and used in conjunction with a refractometer) called a saccharimeter. These instruments use the International Sugar Scale, as defined by the


id: post-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Post_Instrument-0.md
category: reference
title: Post Instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Post_Instrument
date_saved: 2026-05-05T09:43:29.277739+00:00
instance: kb-cron
parent: post-instrument-20260505-0
summary:
The Post Plotting Instrument, or simply Post Instrument and sometimes the Observer Instrument, was the standard optical sighting system used by the UK's Royal Observer Corps (ROC) to determine the location of aircraft. It was used during the period from the mid-1930s into the early 1950s, and was one of the main sources of daytime tracking information during World War II. There were two versions of the Post Instrument, a pre-war model using a pantograph, and a wartime version of somewhat more sophistication. Both required the operator to estimate the altitude of the aircraft and enter that into the device, then point a mechanical indicator, or sight, at the aircraft. The motion of the sight moved an indicator on a small Ordnance Survey National Grid map. The grid location indicated by the pointer was then telephoned to central control rooms, where several such reports were combined to produce a more accurate location estimate. Later models added the Micklethwait Height Corrector, which allowed the posts to measure altitude with some accuracy and thus improve the quality of the measurements. The ROC also developed a methodology that allowed the Post Instrument to be used to produce measurements purely by sound, but it


id: post-instrument-20260505-1
file: data/en.wikipedia.org/wiki/Post_Instrument-1.md
category: reference
title: Post Instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Post_Instrument
date_saved: 2026-05-05T09:43:29.277739+00:00
instance: kb-cron
parent: post-instrument-20260505-0
summary:
== Micklethwait Height Corrector == Wartime models were modified in 1940 with the Micklethwait Height Corrector, named for its inventor, Eric Walter Eustace Micklethwait. Micklethwait was an observer at the Gower Street Post on the roof of a building at University of London, near Euston Square tube station. Formerly a patent clerk, he devised the Corrector and quickly patented it. The Corrector consisted of a second map pointer on a second horizontal slider, with a crank that moved the horizontal slider fore and aft. A second arm suspended from the main sight tube was pushed up and down as the horizontal portion slid. This arm was measured against a short vertical bar marked with altitude corrections. The system indicated only corrections, not the actual altitude. Two or more posts had to work in concert to use the system, using two measured angles and simple trigonometry to solve the altitude. The simplest measurement took place when an aircraft flew directly over one of the posts. Other posts that could see the same aircraft would continue to track the target as normal, set to whatever altitude they had initially estimated. When the first post called that the aircraft was directly overhead, the


id: post-instrument-20260505-2
file: data/en.wikipedia.org/wiki/Post_Instrument-2.md
category: reference
title: Post Instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Post_Instrument
date_saved: 2026-05-05T09:43:29.277739+00:00
instance: kb-cron
parent: post-instrument-20260505-0
summary:
The Observer Corp was an expansion of a system originally set up in World War I to coordinate the reports from observers in the London area, part of the London Air Defence Area (LADA). In this system, originally set up by Edward Ashmore, observers telephoned reports of aircraft to a plotting center in the Horse Guards building in London. Information from the map would then be forwarded to the searchlights and anti-aircraft guns in the LADA area. In the post-World War I era the system was taken over by the Air Defence of Great Britain organization, formally part of the Royal Air Force but containing British Army and Royal Engineer units as well. It was re-organized and expanded, covering not only the London area but adding similar reporting organizations in The Midlands. They also introduced new techniques to deal with faster aircraft. In the new systems, plotters would take the reports from the observers and place a colored marker on a large map inside the indicated grid location. The marker held information about the number and altitude of the aircraft. The marker colors changed every five minutes, based on a sector clock, and when the marker was moved to a


id: pseudoscope-20260505-0
file: data/en.wikipedia.org/wiki/Pseudoscope-0.md
category: reference
title: Pseudoscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pseudoscope
date_saved: 2026-05-05T09:43:30.433063+00:00
instance: kb-cron
parent: pseudoscope-20260505-0
summary:
A pseudoscope is a binocular optical instrument that reverses depth perception. It is used to study human stereoscopic perception. Objects viewed through it appear inside out, for example: a box on a floor would appear as a box-shaped hole in the floor. It typically uses sets of optical prisms, or periscopically arranged mirrors to swap the view of the left eye with that of the right eye. == Purpose == In the 1800s Charles Wheatstone coined the name from the Greek ψευδίς σκοπειν – 'false view'. The device was used to explore his theory of stereo vision. Basically, pseudoscopic vision is three-dimensional vision in reverse. For example, in aerial photography, swimming pools appear to look like buildings and buildings appear to look like swimming pools. In red and green plotters like the Kelsh and Multiplex this is achieved by reversing the lenses on the 3D glasses. The images will be reverse order. The right image will be viewed through the left eye, and the left image will be through the right eye. == Effect == Switching the two pictures in a standard stereoscope changes all the elevated parts into depressions, and vice versa. The pseudoscope also changes convex into concave,


id: pyramid-wavefront-sensor-20260505-0
file: data/en.wikipedia.org/wiki/Pyramid_wavefront_sensor-0.md
category: reference
title: Pyramid wavefront sensor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyramid_wavefront_sensor
date_saved: 2026-05-05T09:43:31.620901+00:00
instance: kb-cron
parent: pyramid-wavefront-sensor-20260505-0
summary:
A pyramid wavefront sensor is a type of a wavefront sensor. It measures the optical aberrations of an optical wavefront. This wavefront sensor uses a pyramidal prism with a large apex angle to split the beam into multiple parts at the geometric focus of a lens. A four-faceted prism, with its tip centered at the peak of the point spread function, will generate four identical pupil images in the absence of optical aberrations. In the presence of optical aberrations, the intensity distribution among the pupils will change. The local wavefront gradients can be obtained by recording the distribution of intensity in the pupil images. The wavefront aberrations can be evaluated from the estimated wavefront gradients. It has potential applications in astronomy and ophthalmology. == Modulation == The prism is often modulated (mechanically moved in a circle/square) for averaging purposes and to make sure that the ray spends an equal fraction of the total time on every face of the pyramidal prism. This makes the wavefront sensor slightly inconvenient to use due to the need for mechanically moving parts – either the prism or the beam is modulated. Using a light diffusing plate, mechanically moving parts can be eliminated. Alternatively, it


id: reynolds-and-branson-20260505-0
file: data/en.wikipedia.org/wiki/Reynolds_and_Branson-0.md
category: reference
title: Reynolds and Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reynolds_and_Branson
date_saved: 2026-05-05T09:43:32.838993+00:00
instance: kb-cron
parent: reynolds-and-branson-20260505-0
summary:
Reynolds & Branson Leeds was a business based at 13 Briggate and 14 Commercial Street in Leeds, England. The business lasted from 1816 (1816) to 1972 (1972). Edward Matterson managed the company in 1822, and William West F.R.S. took over in 1833. The National Archives Records about the company include a day book, sales ledger, and prescription books. The records were created by Reynolds & Branson Ltd. Reynolds & Branson was registered in July 1898 as a limited corporation with a capital of £34,000 in shares of £10 each by Messrs. R. Reynolds, F. W. Branson. No remuneration was given to Mr. R. Reynolds, but a £700 per annum was given to each of the others. In 1890, Richard Reynold's son, Richard Freshfield (Fred) Reynolds was made a partner. The firm was in the business of wholesale and retail for chemists and surgical instrument makers. == Origins == The original company can be traced back to 1816 (see Grace's Guide which is the leading source of historical information on industry and manufacturing in Britain). Edward Matterson was a druggist who ran the firm after being employed by Allen and Hanburys. He was educated at Leeds Grammar School. In 1822 the


id: reynolds-and-branson-20260505-1
file: data/en.wikipedia.org/wiki/Reynolds_and_Branson-1.md
category: reference
title: Reynolds and Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reynolds_and_Branson
date_saved: 2026-05-05T09:43:32.838993+00:00
instance: kb-cron
parent: reynolds-and-branson-20260505-0
summary:
== The war years == During the First World War, he actively pursued efforts to standardize the size and shape of chemical glassware. In 1916, he was elected as an inaugural member of the Society of Glass Technology. He organized research and published works on these topics. Branson sought to secure in Great Britain the manufacturing process for the glass required for the equipment of munition factories.[8][9] Branson contributed a paper on the composition of some types of chemical glassware to the Society of Chemical Industry (J. SOC. Chem. Ind., 1915, 34, 471) in collaboration with his son Frederick Hartridge, a paper to the Transactions of the Society of Glass Technology (1919, 3, 249) "A proposed standard formula for a glass for lamp workers". Branson was chairman until retirement in 1932. His son, Frederick Hartridge, Associate of the Royal Institute of Chemistry AIC, became chairman and managing director of Reynolds & Branson.[5][7] he run the company for 20 years, until his untimely death on 10 February 1952, Frederick Hartridge had appointed his 3 Sons and Daughter as directors of Reynolds & Branson, Frederick Norman the eldest son who attended Ilkley Grammar an all-boys school, Eileen his only daughter, Peter Orchard


id: reynolds-and-branson-20260505-2
file: data/en.wikipedia.org/wiki/Reynolds_and_Branson-2.md
category: reference
title: Reynolds and Branson
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reynolds_and_Branson
date_saved: 2026-05-05T09:43:32.838993+00:00
instance: kb-cron
parent: reynolds-and-branson-20260505-0
summary:
Reynolds and Branson, 1887. Handy Guide to Surgical Instruments and Appliances etc. Reynolds and Branson, 14 Commercial Street, Leeds. Gloucester: John Bellows. 1887. 246p. Reynolds and Branson, 1890. Illustrated Catalogue of Chemical and Physical Apparatus, Pure Chemicals and Reagents. Reynolds and Branson, 14 Commercial Street, Leeds. 1890. 200p. Reynolds and Branson, 1903. Catalogue of Special Preparations. Reynolds and Branson, 14 Commercial Street, Leeds. 1903. 64p. Reynolds and Branson, 1907. Illustrated Catalogue of Optical Lanterns, Slides, Compressed Gases and Accessory Apparatus. Reynolds and Branson, 14 Commercial Street, Leeds. Leeds: McCorquodale & Co. 1907. 204p. Reynolds and Branson, 1908. Illustrated Catalogue of Surgical Instruments and Appliances. Reynolds and Branson, 14 Commercial Street, Leeds. Leeds: Chorley & Pickersgill. 1908. 119p. Reynolds and Branson, 1912. Catalogue of Special Preparations, Surgical Instruments, Trusses etc. Reynolds and Branson, 14 Commercial Street, Leeds. 1912. 84p. Reynolds and Branson, 1912–1920. Catalogue of Laboratory Fittings and Furniture. Reynolds and Branson. 1912–1920. 29p. == Reynolds & Branson Patents == Patents include: #1120 in 1885, #16373 in 1893, #14102 in 1899. Improvements in photographic ‘shutters’ for instantaneous photography. #1650. 1883. Means or apparatus for measuring quantities of highly volatile liquids. No. 3490. 1904. == References == == External links == Reynolds


id: rhinoscope-20260505-0
file: data/en.wikipedia.org/wiki/Rhinoscope-0.md
category: reference
title: Rhinoscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rhinoscope
date_saved: 2026-05-05T09:43:33.971738+00:00
instance: kb-cron
parent: rhinoscope-20260505-0
summary:
A rhinoscope (or nasoscope) is a thin, tube-like instrument used to examine the inside of the nose. A rhinoscope has a light and a lens for viewing and may have a tool to remove tissue. == Types == Rhinoscopy is performed by two procedures. Anterior rhinoscopy using a nasal speculum Posterior rhinoscopy using an endoscopic rhinoscope === Anterior rhinoscopy === In anterior rhinoscopy, the rhinoscope is advanced through the nose to examine the nasal cavity. === Posterior rhinoscopy === In posterior rhinoscopy, the endoscope is advanced through the mouth to examine the back of the nasal cavity above the soft palate, and can be used to visualise the oropharynx below that. Structures seen in posterior rhinoscopy: posterior border of nasal septum, fossa of Roosenmuller, eustachian tube opening and upper surface of soft palate. == References == == External links == Rhinoscope entry in the public domain NCI Dictionary of Cancer Terms This article incorporates public domain material from Dictionary of Cancer Terms. U.S. National Cancer Institute.


id: slit-lamp-20260505-0
file: data/en.wikipedia.org/wiki/Slit_lamp-0.md
category: reference
title: Slit lamp
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slit_lamp
date_saved: 2026-05-05T09:43:35.131086+00:00
instance: kb-cron
parent: slit-lamp-20260505-0
summary:
In ophthalmology and optometry, a slit lamp is an instrument consisting of a high-intensity light source that can be focused to shine a thin sheet of light into the eye. It is used in conjunction with a biomicroscope. The lamp facilitates an examination of the anterior segment and posterior segment of the human eye, which includes the eyelid, sclera, conjunctiva, iris, natural crystalline lens, and cornea. The binocular slit-lamp examination provides a stereoscopic magnified view of the eye structures in detail, enabling anatomical diagnoses to be made for a variety of eye conditions. A second, hand-held lens is used to examine the retina. == History == Two conflicting trends emerged in the development of the slit lamp. One trend originated from clinical research and aimed to apply the increasingly complex and advanced technology of the time. The second trend originated from ophthalmologic practice and aimed at technical perfection and a restriction to useful methods. The first man credited with developments in this field was Hermann von Helmholtz (1850) when he invented the ophthalmoscope. In ophthalmology and optometry, the instrument is called a "slit lamp", although it is more correctly called a "slit lamp instrument". Today's instrument is a combination of


id: slit-lamp-20260505-1
file: data/en.wikipedia.org/wiki/Slit_lamp-1.md
category: reference
title: Slit lamp
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slit_lamp
date_saved: 2026-05-05T09:43:35.131086+00:00
instance: kb-cron
parent: slit-lamp-20260505-0
summary:
== General procedure == While a patient is seated in the examination chair, they rest their chin and forehead on a support area to steady the head. Using the biomicroscope, the ophthalmologist or optometrist then proceeds to examine the patient's eye. A fine strip of paper, stained with fluorescein, a fluorescent dye, may be touched to the side of the eye; this stains the tear film on the surface of the eye to aid examination. The dye is naturally rinsed out of the eye by tears. A subsequent test may involve placing drops in the eye in order to dilate the pupils. The drops take about 15 to 20 minutes to work, after which the examination is repeated, allowing the back of the eye to be examined. Patients will experience some light sensitivity for a few hours after this exam, and the dilating drops may also cause increased pressure in the eye, leading to nausea and pain. Patients who experience serious symptoms are advised to seek medical attention immediately. Adults need no special preparation for the test; however children may need some preparation, depending on age, previous experiences, and level of trust. == Illumination == Various methods of slitlamp illumination


id: slit-lamp-20260505-2
file: data/en.wikipedia.org/wiki/Slit_lamp-2.md
category: reference
title: Slit lamp
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Slit_lamp
date_saved: 2026-05-05T09:43:35.131086+00:00
instance: kb-cron
parent: slit-lamp-20260505-0
summary:
Fundus observation is generally performed via ophthalmoscopy, where the observer (fundus camera or observing eye) is focused to infinity, which brings the subject's fundus into focus due to the refractive power of the subject's optical media. In contrast, the microscope in slit lamp biomicroscopy is focused to the anterior segments of the eye, such that direct observation of the fundus is impossible due to the subject's refractive power. However, with the use of auxiliary optics, the fundus can be brought within the focusing range of the microscope. These optics usually take the form of a lens placed on or near the subject's cornea, which range in optical properties and practical application. Watzke–Allen test is a test used in diagnosis of a full thickness macular hole and also to assess retinal function after surgical closure of the hole, with the help of slit lamp. == Light filters == Most slit-lamps have five light filters options: Unfiltered, Heat absorption- for increased patient comfort Grey filter, Red free- for better visualisation of nerve fibre layer and haemorrhages and blood vessels. Cobalt blue- after staining with fluorescein dye, for seeing corneal ulcers, contact lens fitting, Seidel's test === Cobalt blue light === Slit lamps


id: spherometer-20260505-0
file: data/en.wikipedia.org/wiki/Spherometer-0.md
category: reference
title: Spherometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Spherometer
date_saved: 2026-05-05T09:43:36.305316+00:00
instance: kb-cron
parent: spherometer-20260505-0
summary:
A spherometer is an instrument used for the precise measurement of the radius of curvature of a curved surface. Originally, these instruments were primarily used by opticians to measure the curvature of the surface of a lens. == Design == A spherometer usually consists of: A frame with three legs, arranged in an equilateral triangle of known radius. The outer legs of some spherometers can be moved to a set of inner holes in order to accommodate a smaller surface. The lower ends of the legs are finely tapered and terminate in hemispheres. A central leg, which can be raised or lowered via a screw. A reading device for measuring the distance the central leg is moved. Often this consists of a marked dial attached to the top of the screw and a vertical scale attached to the frame. This both indicates the number of turns of the screw and serves as an index for reading the divisions on the dial. A lens may be fitted in order to magnify the scale divisions. On new spherometers, the vertical scale is marked off in units of 0.5 mm. One complete turn of the dial also corresponds to 0.5 mm and each


id: stauroscope-20260505-0
file: data/en.wikipedia.org/wiki/Stauroscope-0.md
category: reference
title: Stauroscope
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Stauroscope
date_saved: 2026-05-05T09:43:37.484613+00:00
instance: kb-cron
parent: stauroscope-20260505-0
summary:
A stauroscope is an optical instrument used in determining the position of the planes of light-vibration in sections of crystals. The word comes from Greek for cross + scope. It was invented by Wolfgang Franz von Kobell in 1855. == References ==


id: stereoautograph-20260505-0
file: data/en.wikipedia.org/wiki/Stereoautograph-0.md
category: reference
title: Stereoautograph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Stereoautograph
date_saved: 2026-05-05T09:43:38.646837+00:00
instance: kb-cron
parent: stereoautograph-20260505-0
summary:
The stereoautograph is a complex opto-mechanical measurement instrument for the evaluation of analog or digital photograms. It is based on the stereoscopy effect by using two aero photos or two photograms of the topography or of buildings from different standpoints. It was invented by Eduard von Orel in 1907. The photograms or photographic plates are oriented by measured passpoints in the field or on the building. This procedure can be carried out digitally (by methods of triangulation and projective geometry or iteratively (repeated angle corrections by congruent rays). The accuracy of modern autographs is about 0.001 mm. Well known are the instruments of the companies Wild Heerbrugg (Leica), e.g. analog A7, B8 of the 1980s and the digital autographs beginning in the 1990s, or special instruments of Zeiss and Contraves. == References == Gilbert Willy U.S. patent 1,477,082 Military Topography and Photography by Floyd D. Carlock, U.S. Army, 1916, p.104 ff, with photos (Available online at Google Books)


id: theodolite-20260505-0
file: data/en.wikipedia.org/wiki/Theodolite-0.md
category: reference
title: Theodolite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Theodolite
date_saved: 2026-05-05T09:43:39.815016+00:00
instance: kb-cron
parent: theodolite-20260505-0
summary:
A theodolite () is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying, but it is also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. It consists of a moveable telescope mounted so it can rotate around horizontal and vertical axes and provide angular readouts. These indicate the orientation of the telescope, and are used to relate the first point sighted through the telescope to subsequent sightings of other points from the same theodolite position. Depending on the instrument, these angles can be measured with accuracies down to microradians or seconds of arc. From these readings a plan can be drawn, or objects can be positioned in accordance with an existing plan. The modern theodolite has evolved into what is known as a total station where angles and distances are measured electronically, and are read directly to computer memory. A transit theodolite has a telescope short enough to rotate about the instrument's horizontal trunnion axis, turning the scope through the vertical plane and its zenith; vertical rotation in non-transit instruments is restricted to a limited


id: theodolite-20260505-1
file: data/en.wikipedia.org/wiki/Theodolite-1.md
category: reference
title: Theodolite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Theodolite
date_saved: 2026-05-05T09:43:39.815016+00:00
instance: kb-cron
parent: theodolite-20260505-0
summary:
=== Historical background === Prior to the theodolite, instruments such as the groma, geometric square and the dioptra, and various other graduated circles (see circumferentor) and semicircles (see graphometer) were used to obtain either vertical or horizontal angle measurements. Over time their functions were combined into a single instrument that could measure both angles simultaneously. The first occurrence of the word theodolite is found in the surveying textbook A geometric practice named Pantometria (1571) by Leonard Digges. The origin of the word is unknown. The first part of the Neo-Latin theo-delitus might stem from the Greek θεᾶσθαι 'to behold or look attentively upon' The second part is often attributed to an unscholarly variation of the Greek word: δῆλος 'evident' or 'clear'. Other Neo-Latin or Greek derivations have been suggested as well as an English origin from alidade. The early forerunners of the theodolite were sometimes azimuth instruments for measuring horizontal angles, while others had an altazimuth mount for measuring horizontal and vertical angles. Gregorius Reisch illustrated an altazimuth instrument in the appendix of his 1512 book Margarita Philosophica. Martin Waldseemüller, a topographer and cartographer made the device in that year calling it the polimetrum. In Digges's book of 1571, the


id: theodolite-20260505-2
file: data/en.wikipedia.org/wiki/Theodolite-2.md
category: reference
title: Theodolite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Theodolite
date_saved: 2026-05-05T09:43:39.815016+00:00
instance: kb-cron
parent: theodolite-20260505-0
summary:
Triangulation, as invented by Gemma Frisius around 1533, consists of making direction plots of the surrounding landscape from two separate standpoints. The two graphing papers are superimposed, providing a scale model of the landscape, or rather the targets in it. The true scale can be obtained by measuring one distance both in the real terrain and in the graphical representation. Modern triangulation as, e.g., practiced by Willebrord Snellius, is the same procedure executed by numerical means. Photogrammetric block adjustment of stereo pairs of aerial photographs is a modern, three-dimensional variant. In the late 1780s, Jesse Ramsden, a Yorkshireman from Halifax, England, who had developed the dividing engine for dividing angular scales accurately to within a second of arc (≈ 0.0048 mrad or 4.8 μrad), was commissioned to build a new instrument for the British Ordnance Survey. The Ramsden theodolite was used over the next few years to map the whole of southern Britain by triangulation. In network measurement, the use of forced centering speeds up operations while maintaining the highest precision. The theodolite or the target can be rapidly removed from, or socketed into, the forced centering plate with sub-millimeter precision. Nowadays GPS antennas used for geodetic positioning use a


id: theodolite-20260505-3
file: data/en.wikipedia.org/wiki/Theodolite-3.md
category: reference
title: Theodolite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Theodolite
date_saved: 2026-05-05T09:43:39.815016+00:00
instance: kb-cron
parent: theodolite-20260505-0
summary:
A gyrotheodolite is used when the north-south reference bearing of the meridian is required in the absence of astronomical star sights. This occurs mainly in the underground mining industry and in tunnel engineering. For example, where a conduit must pass under a river, a vertical shaft on each side of the river might be connected by a horizontal tunnel. A gyrotheodolite can be operated at the surface and then again at the foot of the shafts to identify the directions needed to tunnel between the base of the two shafts. Unlike an artificial horizon or inertial navigation system, a gyrotheodolite cannot be relocated while it is operating. It must be restarted again at each site. The gyrotheodolite comprises a normal theodolite with an attachment that contains a gyrocompass, a device which senses the rotation of the Earth in order to find true north and thus, in conjunction with the direction of gravity, the plane of the meridian. The meridian is the plane that contains both the axis of the Earth's rotation and the observer. The intersection of the meridian plane with the horizontal defines the true north-south direction found in this way. Unlike magnetic compasses, gyrocompasses are able to find


id: tiny-ionospheric-photometer-20260505-0
file: data/en.wikipedia.org/wiki/Tiny_Ionospheric_Photometer-0.md
category: reference
title: Tiny Ionospheric Photometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tiny_Ionospheric_Photometer
date_saved: 2026-05-05T09:43:40.992547+00:00
instance: kb-cron
parent: tiny-ionospheric-photometer-20260505-0
summary:
The tiny ionospheric photometer (TIP) is a small space-based photometer that observes the Earth's ionosphere at 135.6 nm. The TIP instruments were designed and built by the US Naval Research Laboratory (NRL) and are a part of the COSMIC program. == Operation == Although each TIP instrument is fairly simple in design and operation, the value of this instrument is that six of them were launched at once, and they observe the Earth simultaneously from three orbital planes spaced equally apart around the Earth. The data of this instrument when combined with the data from the other COSMIC payloads allows a 3D tomographic analysis of the Earth's ionosphere to be performed. == See also == Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) == References == == External links == Official Website


id: total-station-20260505-0
file: data/en.wikipedia.org/wiki/Total_station-0.md
category: reference
title: Total station
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Total_station
date_saved: 2026-05-05T09:43:42.149349+00:00
instance: kb-cron
parent: total-station-20260505-0
summary:
A total station or total station theodolite is an electronic/optical instrument used for surveying and building construction. It is an electronic transit theodolite integrated with electronic distance measurement (EDM) to measure both vertical and horizontal angles and the slope distance from the instrument to a particular point, and an on-board computer to collect data and perform triangulation and position resection and intersection calculations. Robotic or motorized total stations allow the operator to control the instrument from a distance via remote control. In theory, this eliminates the need for an assistant staff member, as the operator holds the retroreflector and controls the total station from the observed point. In practice, however, an assistant surveyor is often needed when the surveying is being conducted in busy areas such as on a public carriageway or construction site. This is to prevent people from disrupting the total station as they walk past, which would necessitate resetting the tripod and re-establishing a baseline. Additionally, an assistant surveyor discourages opportunistic theft, which is not uncommon due to the value of the instrument. If all else fails, most total stations have serial numbers. In the United States the National Society of Professional Surveyors hosts a registry of


id: total-station-20260505-1
file: data/en.wikipedia.org/wiki/Total_station-1.md
category: reference
title: Total station
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Total_station
date_saved: 2026-05-05T09:43:42.149349+00:00
instance: kb-cron
parent: total-station-20260505-0
summary:
=== Mining === Total stations are the primary survey instrument used in mining surveying. A total station is used to record the absolute location of the tunnel walls, ceilings (backs), and floors, as the drifts of an underground mine are driven. The recorded data are then downloaded into a CAD program and compared to the designed layout of the tunnel. The survey party installs control stations at regular intervals. These are small steel plugs installed in pairs in holes drilled into walls or the back. For wall stations, two plugs are installed in opposite walls, forming a line perpendicular to the drift. For back stations, two plugs are installed in the back, forming a line parallel to the drift. A set of plugs can be used to locate the total station set up in a drift or tunnel by processing measurements to the plugs by intersection and resection. === Mechanical and electrical construction === Total stations have become the highest standard for most forms of construction layout. They are most often used in the X and Y axes to lay out the locations of penetrations out of the underground utilities into the foundation, between floors of a structure, as well


id: upside-down-goggles-20260505-0
file: data/en.wikipedia.org/wiki/Upside_down_goggles-0.md
category: reference
title: Upside down goggles
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Upside_down_goggles
date_saved: 2026-05-05T09:43:43.314607+00:00
instance: kb-cron
parent: upside-down-goggles-20260505-0
summary:
Upside down goggles, also known as "invertoscopes" by Russian researchers, are optical instruments that invert the image received by the retinas upside down. They are used to study human visual perception, particularly psychological process of building a visual image in the brain. Objects viewed through such a device appear upside down and mirrored. They are constructed using sets of optical right-angle prisms, concave mirrors, or a mirror plus right-angle prisms with unequal cathethus. == Purpose == Upside down goggles can be used to demonstrate human adaptation to inverted vision, and as a method of preventing motion sickness. Hubert Dolezal recommended using upside down goggles for "nausea adaptation" for space travel. They can also be used to train spatial abilities and possibly cognitive functions. == Effect == Under normal circumstances, an inverted image is formed on the retina of the eye. With the help of upside down goggles, the image on the retina of the observer's eyes is turned back (straightened) and thus the space around the observer looks upside down. == History == George M. Stratton designed the first upside down goggles for a psychological experiment. His device used short-focus lenses. Stratton used a one-tube, monocular device because this also


id: w-watson-and-son-20260505-0
file: data/en.wikipedia.org/wiki/W._Watson_and_Son-0.md
category: reference
title: W. Watson and Son
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/W._Watson_and_Son
date_saved: 2026-05-05T09:43:44.517589+00:00
instance: kb-cron
parent: w-watson-and-son-20260505-0
summary:
W. Watson and Son was an optical instrument maker. In 1837, the William Watson business was established in London for the manufacture of optical instruments. By the 1840s, the company moved into lanterns, slides and associated equipment. In 1868, the name was changed to W. Watson & Son and by this time were located at 313 High Holborn, London. In the 1870s, the company added photographic equipment and became known as a leading manufacturer of the Highest Class Photographic Instruments and Apparatus in England. Into the 1940s, the company remained at 313 High Holborn. == W. Watson and Sons == On 9 January 1881 William Watson died. In 1883, the name of the company was changed to W. Watson & Sons as the son, Charles Henry Watson joined the business. The 1883 Kelly's Business Directory listed both Charles Henry Watson and Henry Watson as associated with the Watson & Sons company located at 23 Walton Street, Aylesbury, England. In 1889, the company participated in the formation of a Photographic Trades Section of the London Chamber of Commerce. In 1894, the company exhibited scientific instruments at the Antwerp Exhibition. In the 1890s, the business continued to grow and advertised in catalogues


id: wavefront-curvature-sensor-20260505-0
file: data/en.wikipedia.org/wiki/Wavefront_curvature_sensor-0.md
category: reference
title: Wavefront curvature sensor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wavefront_curvature_sensor
date_saved: 2026-05-05T09:43:45.713577+00:00
instance: kb-cron
parent: wavefront-curvature-sensor-20260505-0
summary:
A wavefront curvature sensor is a device for measuring the aberrations of an optical wavefront. Like a Shack–Hartmann wavefront sensor it uses an array of small lenses (or lenslets) to focus the wavefront into an array of spots. Unlike the Shack-Hartmann, which measures the position of the spots, the curvature sensor measures the intensity on either side of the focal plane. If a wavefront has a phase curvature, it will alter the position of the focal spot along the axis of the beam, thus by measuring the relative intensities in two places the curvature can be deduced. == See also == Adaptive optics Wavefront sensor == Sources == Roddier, François (1988). "Curvature sensing and compensation: a new concept in adaptive optics". Applied Optics. 27 (7): 1223–1225. Bibcode:1988ApOpt..27.1223R. doi:10.1364/AO.27.001223. PMID 20531543. Roddier, François; Roddier, Claude (March 1988). Ulrich, M. H. (ed.). "Curvature Sensing and Compensation: A New Concept in Adaptive Optics". Very Large Telescopes and Their Instrumentation. European Southern Observatory Conference and Workshop Proceedings. 30 (7): 1223–5. Bibcode:1988ESOC...30..667R. doi:10.1364/AO.27.001223. PMID 20531543.


id: accelerograph-20260505-0
file: data/en.wikipedia.org/wiki/Accelerograph-0.md
category: reference
title: Accelerograph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Accelerograph
date_saved: 2026-05-05T09:43:48.291339+00:00
instance: kb-cron
parent: accelerograph-20260505-0
summary:
An accelerograph can be referred to as a strong-motion instrument or seismograph, or simply an earthquake accelerometer. They are usually constructed as a self-contained box, which previously included a paper or film recorder (an analogue instrument) but now they often record directly on digital media and then the data is transmitted via the Internet. Accelerographs are useful for when the earthquake ground motion is so strong that it causes the more sensitive seismometers to go off-scale. There is an entire science of strong ground motion, that is dedicated to studying the shaking in the vicinity of earthquakes (roughly within about 100 km of the fault rupture). Accelerographs record the acceleration of the ground with respect to time. This recording is often called an accelerograms, strong-motion record or acceleration time-history. From this record strong-motion intensity measures (IMs, also called parameters) can be computed. The simplest of which is peak ground acceleration (PGA). Other IMs include Arias intensity, peak ground velocity (PGV), for which the accelerogram needs to be integrated once, peak ground displacement (PGD), for which double integration is required. Often a response spectrum is computed to show how the earthquake would affect structures of different natural frequencies or periods. These


id: coconet-20260505-0
file: data/en.wikipedia.org/wiki/COCONet-0.md
category: reference
title: COCONet
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/COCONet
date_saved: 2026-05-05T09:43:49.481321+00:00
instance: kb-cron
parent: coconet-20260505-0
summary:
Continuously Operating Caribbean GPS Observational Network (COCONet) was a global positioning system (GPS) observation network that spanned across the Caribbean and the neighboring area It was part of UNAVCO (University Navstar Corporation). UNAVCO and IRIS (Incorporated Research Institutions for Seismology) Consortium later merged to create EarthScope Consortium in 2023. The project was initiated after the devastation of the 2010 Haiti Earthquake, which was a 7.0 Mw earthquake. Starting from 2011, UNAVCO built and operated COCONet for the National Science Foundation (NSF). It was a network of continuous GPS meteorology or cGPS/Met sites. Along with the NSF-funded TLALOCNet GPS network in Mexico, the two networks of cGPS-Met instrumentation were available to support research in Mexico, Central America, and the Caribbean. == Function == The purpose of COCOnet was to: Provide details on the tectonics of the entire Caribbean region. Enhance atmospheric observations that can be used for testing and validation of climate and weather models. Improve the analysis of local geodetic (the science of planetary measurement) measurements by providing access to an integrated backbone electronic network of reference stations. Increase our ability to model and predict the natural hazards (earthquakes, hurricanes and so on) in the region. To accomplish the function


id: galperin-configuration-20260505-0
file: data/en.wikipedia.org/wiki/Galperin_configuration-0.md
category: reference
title: Galperin configuration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galperin_configuration
date_saved: 2026-05-05T09:43:50.630864+00:00
instance: kb-cron
parent: galperin-configuration-20260505-0
summary:
Galperin configuration are a particular configuration of sensing elements found in a class of seismic instruments measuring ground motion and are named after Soviet seisomologist Evsey Iosifovich Galperin, who introduced it in 1955 for petroleum exploration. == Description == Common triaxial seismometers provide signal outputs in three orthogonal axes oriented towards east–west (E), north–south (N) and up-down (Z), i.e. in the Cartesian coordinate system. In contrast, the Galperin configuration consists of three orthogonal axes (U, V, W) that are oriented at precisely the same angle with respect to the horizontal plane (α=35.26°). The projection of all three axes onto the horizontal plane are all separated by 120°, which results in the "symmetric triaxial" design. The recordings acquired with the Galperin configuration are brought to the Cartesian coordinate system by the following coordinate transformation, where β=30°: [ E N Z ] = [ − cos ⁡ α cos ⁡ α sin ⁡ β cos ⁡ α sin ⁡ β 0 cos ⁡ α cos ⁡ β − cos ⁡ α cos ⁡ β sin ⁡ α sin ⁡ α sin ⁡ α ] [ U V W ] {\displaystyle {\begin{bmatrix}E\\N\\Z\end{bmatrix}}={\begin{bmatrix}-\cos \alpha &\cos \alpha \sin \beta &\cos \alpha \sin \beta \\0&\cos \alpha


id: geophone-20260505-0
file: data/en.wikipedia.org/wiki/Geophone-0.md
category: reference
title: Geophone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Geophone
date_saved: 2026-05-05T09:43:51.799682+00:00
instance: kb-cron
parent: geophone-20260505-0
summary:
A geophone is a device that converts ground movement (velocity) into voltage, which may be recorded at a recording station. The deviation of this measured voltage from the base line is called the seismic response and is analyzed for structure of the Earth. == Etymology == The term geophone derives from the Greek word "γῆ (ge) " meaning "earth" and "phone" meaning "sound". == Construction == Geophones have historically been passive analog devices and typically comprise a spring-mounted wire coil moving within the field of a case-mounted permanent magnet to generate an electrical signal. Recent designs have been based on microelectromechanical systems (MEMS) technology which generates an electrical response to ground motion through an active feedback circuit to maintain the position of a small piece of silicon. The response of a coil/magnet geophone is proportional to ground velocity, while MEMS devices usually respond proportional to acceleration. MEMS have a much higher noise level (50 dB velocity higher) than geophones and can only be used in strong motion or active seismic applications. == Frequency response == The frequency response of a geophone is that of a harmonic oscillator, fully determined by corner frequency (typically around 10 Hz) and damping (typically 0.707).


id: mermaid-20260505-0
file: data/en.wikipedia.org/wiki/MERMAID-0.md
category: reference
title: MERMAID
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MERMAID
date_saved: 2026-05-05T09:43:53.042340+00:00
instance: kb-cron
parent: mermaid-20260505-0
summary:
MERMAID is a marine scientific instrument platform, short for Mobile Earthquake Recorder for Marine Areas by Independent Divers. MERMAID evolved from a first prototype, developed and built by Scripps Institution of Oceanography in partnership with Princeton University, to a second, built by Teledyne Webb Research in collaboration with the University of Nice Sophia Antipolis, and now third-generation model, operational today, commercialized by OSEAN SAS in Le Pradet, France. Fourth-generation models add hydrographic monitoring capability to complement the acoustic sensor suite, and are designed to carry out measurement profiles to depths exceeding 4,000 m. MERMAID is a freely-drifting float equipped with a hydrophone to collect hydroacoustic data for the study of earthquakes worldwide. Typically floating at a parking depth of 1500 m, the instrument uses a buoyancy engine (a hydraulic oil bladder system) to return to the surface for triggered data transmission (on average every 6–7 days) via the Iridium satellite constellation, to respond to on-demand data requests, and to receive mission parameter updates. MERMAID carries lithium-ion batteries, sufficient to power about 250 descend/ascend cycles, which translates to an instrument autonomy of about 5 years. A pressure sensor monitors descent depth, and a GPS receiver provides location and time corrections during


id: ocean-bottom-seismometer-20260505-0
file: data/en.wikipedia.org/wiki/Ocean-bottom_seismometer-0.md
category: reference
title: Ocean-bottom seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ocean-bottom_seismometer
date_saved: 2026-05-05T09:43:54.235687+00:00
instance: kb-cron
parent: ocean-bottom-seismometer-20260505-0
summary:
An ocean-bottom seismometer (OBS) is a seismometer that is designed to record the earth's motion under oceans and lakes from man-made sources and natural sources. Sensors at the sea floor are used to observe acoustic and seismic events. Seismic and acoustic signals may be caused by different sources, by earthquakes and tremors as well as by artificial sources. Computing and analyzing the data yields information about the kind of source and, in case of natural seismic events, the geophysics and geology of the sea floor and the deeper crust. The deployment of OBS along a profile will give information about the deep structure of the Earth's crust and upper mantle in offshore areas. OBS may be equipped with a maximum of a three-component geophone in addition to a hydrophone, and thus it needs a capacity of more than 144 Mbytes, which would be the minimum for adequate MCS profiling. In a typical survey, the instruments should be operational for several days (deployments can exceed 12 months), which requires a data storage capacity of more than 500 Mbyte. Other experiments, such as tomographic investigations within a 3D-survey or seismological monitoring, demand even larger capacities. == Instrument package == The OBS consists


id: ocean-bottom-seismometer-20260505-1
file: data/en.wikipedia.org/wiki/Ocean-bottom_seismometer-1.md
category: reference
title: Ocean-bottom seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ocean-bottom_seismometer
date_saved: 2026-05-05T09:43:54.235687+00:00
instance: kb-cron
parent: ocean-bottom-seismometer-20260505-0
summary:
== Disadvantages == The environment of these deployments complicates standard methods that are used in analyzing the data because of the ocean on top of the seismometer, as opposed to free-air above a typical land station. These seismometers also have a decreased signal-to-noise ratio because of noise created by the movement of the oceans due to wind driven tides, particularly at periods of 7 and 14 seconds. This long period motion and current flowing around the seismometer can create problems of long period noise on the horizontal components because the soft (saturated) sediment that the seismometer is resting on is more susceptible to allow the seismometer to tilt and ideally, the horizontal component will not move and be perpendicular to gravity to get the best results out of the seismometer. The saturated sediment also reduces signal-to-noise ratio significantly because the velocity of the P and S waves decreases and the seismic waves get trapped in the sediment layer creating a large amplitude ringing due to the conservation of energy. == Notable deployments == One of the largest OBS deployments ever was The Big Mantle Electromagnetic and Tomography (Big MELT) Experiment, involving almost 100 OBS in the East Pacific Rise with


id: seismic-array-20260505-0
file: data/en.wikipedia.org/wiki/Seismic_array-0.md
category: reference
title: Seismic array
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismic_array
date_saved: 2026-05-05T09:43:55.448067+00:00
instance: kb-cron
parent: seismic-array-20260505-0
summary:
A seismic array is a system of linked seismometers arranged in a regular geometric pattern (cross, circle, rectangular etc.) to increase sensitivity to earthquake and explosion detection. A seismic array differs from a local network of seismic stations mainly by the techniques used for data analysis. The data from a seismic array is obtained using special digital signal processing techniques such as beamforming, which suppress noises and thus enhance the signal-to-noise ratio (SNR). The earliest seismic arrays were built in the 1950s in order to improve the detection of nuclear tests worldwide. Many of these deployed arrays were classified until the 1990s. Today they have become part of the International Monitoring System (IMS) as primary or auxiliary stations. Seismic arrays are not only used to monitor earthquakes and nuclear tests but also used as a tool for investigating nature and source regions of microseisms as well as locating and tracking volcanic tremor and analyzing complex seismic wave-field properties in volcanic areas. == Layout == Seismic arrays can be classified by size, which is defined by the array's aperture given by the largest distance between the single seismometers. The sensors in a seismic array are arranged in different geometric patterns horizontally.


id: seismic-array-20260505-1
file: data/en.wikipedia.org/wiki/Seismic_array-1.md
category: reference
title: Seismic array
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismic_array
date_saved: 2026-05-05T09:43:55.448067+00:00
instance: kb-cron
parent: seismic-array-20260505-0
summary:
Assuming that the noise nj(t) has a normal amplitude distribution with zero mean and variance σ2 at all sites, then the variance of the noise after summation is σ s 2 = M σ 2 {\displaystyle \sigma _{s}^{2}=M\sigma ^{2}} and the standard deviation is M σ 2 {\displaystyle {\sqrt {M}}\sigma ^{2}} . That means the standard deviation of the noise is multiplied by M {\displaystyle {\sqrt {M}}} while the coherent signal is multiplied by M {\displaystyle M} . The theoretical improvement of the SNR by beamforming (aka array gain) will be G = M {\displaystyle G={\sqrt {M}}} for an array containing M sites. ==== The N-th root process ==== N-th root process is a non-linear method to enhance the SNR during beamforming. Before summing up the single seismic traces, the N-th root is calculated for each trace retaining the sign information. signum{wj(t)} is a function defined as -1 or +1, depending on the sign of the actual sample wj(t). N is an integer that has to be chosen by the analyst B N ( t ) = ∑ j = 1 M n j ( t + τ j ) N ⋅ s i g n u m { w


id: seismic-array-20260505-2
file: data/en.wikipedia.org/wiki/Seismic_array-2.md
category: reference
title: Seismic array
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismic_array
date_saved: 2026-05-05T09:43:55.448067+00:00
instance: kb-cron
parent: seismic-array-20260505-0
summary:
E ( ω , k 0 − k ) = 1 2 π ∫ − ∞ ∞ | w ¯ ( ω ) | 2 ⋅ | C ( k 0 − k ) | 2 d ω {\displaystyle E(\omega ,k_{0}-k)={\frac {1}{2\pi }}\int _{-\infty }^{\infty }|{\bar {w}}(\omega )|^{2}\cdot |C(k_{0}-k)|^{2}d\omega } , where C ( k 0 − k ) = 1 M ∑ j = 1 M e i w r j ( k 0 − k ) {\displaystyle C(k_{0}-k)={\frac {1}{M}}\sum _{j=1}^{M}e^{iwr_{j}(k_{0}-k)}} This equation is called the transfer function of an array. If the slowness difference is zero, the factor | C ( k 0 − k ) | 2 {\displaystyle |C(k_{0}-k)|^{2}} becomes 1.0 and the array is optimally tuned for this slowness. All other energy propagating with a different slowness will be suppressed. === Slowness estimation === Slowness estimation is a matter of forming beams with different slowness vectors and comparing the amplitudes or the power of the beams, and finding out the best beam by looking for the vapp and backazimuth combination with the highest energy on the beam. ==== f-k analysis ==== Frequency-wavenumber analysis is used as a reference tool in array processing for estimating slowness. This


id: seismometer-20260505-0
file: data/en.wikipedia.org/wiki/Seismometer-0.md
category: reference
title: Seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismometer
date_saved: 2026-05-05T09:43:56.624148+00:00
instance: kb-cron
parent: seismometer-20260505-0
summary:
A seismometer is an instrument that responds to ground displacement and shaking caused by quakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output of such a device—formerly recorded on paper (see picture) or film, now recorded and processed digitally—is a seismogram. Such data is used to locate and characterize earthquakes, and to study the internal structure of Earth. == Basic principles == A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical ground motion. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a seismogram. Any movement from the ground moves the frame. The mass tends not to move because of its inertia, and by measuring the movement between the frame and the mass, the motion of the ground can be determined. Early seismometers used optical levers or mechanical linkages to amplify the small motions


id: seismometer-20260505-1
file: data/en.wikipedia.org/wiki/Seismometer-1.md
category: reference
title: Seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismometer
date_saved: 2026-05-05T09:43:56.624148+00:00
instance: kb-cron
parent: seismometer-20260505-0
summary:
Some secondary sources mention unverified claims that a device resembling an earthquake detector may have existed in Ancient Egypt, but as of January 2026, no reliable historical sources confirm this, and the earliest well-documented seismoscope was invented in China by Zhang Heng in AD 132. In AD 132, Zhang Heng of China's Han dynasty is said to have invented the first seismoscope (by the definition above), which was called Houfeng Didong Yi (translated as, "instrument for measuring the seasonal winds and the movements of the Earth"). The description we have, from the History of the Later Han Dynasty, says that it was a large bronze vessel, about 2 meters in diameter; at eight points around the top were dragon's heads holding bronze balls. When there was an earthquake, one of the dragons' mouths would open and drop its ball into a bronze toad at the base, making a sound and supposedly showing the direction of the earthquake. On at least one occasion, probably at the time of a large earthquake in Gansu in AD 143, the seismoscope indicated an earthquake even though one was not felt. The available text says that inside the vessel was a central column that could


id: seismometer-20260505-2
file: data/en.wikipedia.org/wiki/Seismometer-2.md
category: reference
title: Seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismometer
date_saved: 2026-05-05T09:43:56.624148+00:00
instance: kb-cron
parent: seismometer-20260505-0
summary:
=== Early Modern designs (1839–1880) === In response to a series of earthquakes near Comrie in Scotland in 1839, a committee was formed in the United Kingdom in order to produce better detection devices for earthquakes. The outcome of this was an inverted pendulum seismometer constructed by James David Forbes, first presented in a report by David Milne-Home in 1842, which recorded the measurements of seismic activity through the use of a pencil placed on paper above the pendulum. The designs provided did not prove effective, according to Milne's reports. It was Milne who coined the word seismometer in 1841, to describe this instrument. In 1843, the first horizontal pendulum was used in a seismometer, reported by Milne (though it is unclear if he was the original inventor). After these inventions, Robert Mallet published an 1848 paper where he suggested ideas for seismometer design, suggesting that such a device would need to register time, record amplitudes horizontally and vertically, and ascertain direction. His suggested design was funded, and construction was attempted, but his final design did not fulfill his expectations and suffered from the same problems as the Forbes design, being inaccurate and not self-recording. Karl Kreil constructed a seismometer


id: seismometer-20260505-3
file: data/en.wikipedia.org/wiki/Seismometer-3.md
category: reference
title: Seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismometer
date_saved: 2026-05-05T09:43:56.624148+00:00
instance: kb-cron
parent: seismometer-20260505-0
summary:
In 1880, the first horizontal pendulum seismometer was developed by the team of John Milne, James Alfred Ewing and Thomas Gray, who worked as foreign-government advisors in Japan, from 1880 to 1895. Milne, Ewing and Gray, all having been hired by the Meiji Government in the previous five years to assist Japan's modernization efforts, founded the Seismological Society of Japan in response to an Earthquake that took place on February 22, 1880, at Yokohama (Yokohama earthquake). Two instruments were constructed by Ewing over the next year, one being a common-pendulum seismometer and the other being the first seismometer using a damped horizontal pendulum. The innovative recording system allowed for a continuous record, the first to do so. The first seismogram was recorded on 3 November 1880 on both of Ewing's instruments. Modern seismometers would eventually descend from these designs. Milne has been referred to as the 'Father of modern seismology' and his seismograph design has been called the first modern seismometer. This produced the first effective measurement of horizontal motion. Gray would produce the first reliable method for recording vertical motion, which produced the first effective 3-axis recordings. An early special-purpose seismometer consisted of a large, stationary pendulum, with a


id: seismometer-20260505-4
file: data/en.wikipedia.org/wiki/Seismometer-4.md
category: reference
title: Seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismometer
date_saved: 2026-05-05T09:43:56.624148+00:00
instance: kb-cron
parent: seismometer-20260505-0
summary:
Modern instruments use electronic sensors, amplifiers, and recording devices. Most are broadband covering a wide range of frequencies. Some seismometers can measure motions with frequencies from 500 Hz to 0.00118 Hz (1/500 = 0.002 seconds per cycle, to 1/0.00118 = 850 seconds per cycle). The mechanical suspension for horizontal instruments remains the garden-gate described above. Vertical instruments use some kind of constant-force suspension, such as the LaCoste suspension. The LaCoste suspension uses a zero-length spring to provide a long period (high sensitivity). Some modern instruments use a "triaxial" or "Galperin" design, in which three identical motion sensors are set at the same angle to the vertical but 120 degrees apart on the horizontal. Vertical and horizontal motions can be computed from the outputs of the three sensors. Seismometers unavoidably introduce some distortion into the signals they measure, but professionally designed systems have carefully characterized frequency transforms. Modern sensitivities come in three broad ranges: geophones, 50 to 750 V/m; local geologic seismographs, about 1,500 V/m; and teleseismographs, used for world survey, about 20,000 V/m. Instruments come in three main varieties: short-period, long-period and broadband. The short- and long-period instruments measure velocity and are very sensitive; however they 'clip' the signal or


id: seismometer-20260505-5
file: data/en.wikipedia.org/wiki/Seismometer-5.md
category: reference
title: Seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seismometer
date_saved: 2026-05-05T09:43:56.624148+00:00
instance: kb-cron
parent: seismometer-20260505-0
summary:
=== Interconnected seismometers === Seismometers spaced in a seismic array can also be used to precisely locate, in three dimensions, the source of an earthquake, using the time it takes for seismic waves to propagate away from the hypocenter, the initiating point of fault rupture (See also Earthquake location). Interconnected seismometers are also used, as part of the International Monitoring System to detect underground nuclear test explosions, as well as for Earthquake early warning systems. These seismometers are often used as part of a large-scale governmental or scientific project, but some organizations such as the Quake-Catcher Network, can use residential size detectors built into computers to detect earthquakes as well. In reflection seismology, an array of seismometers image sub-surface features. The data are reduced to images using algorithms similar to tomography. The data reduction methods resemble those of computer-aided tomographic medical imaging X-ray machines (CAT-scans), or imaging sonars. A worldwide array of seismometers can actually image the interior of the Earth in wave-speed and transmissivity. This type of system uses events such as earthquakes, impact events or nuclear explosions as wave sources. The first efforts at this method used manual data reduction from paper seismograph charts. Modern digital seismograph records


id: strainmeter-20260505-0
file: data/en.wikipedia.org/wiki/Strainmeter-0.md
category: reference
title: Strainmeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Strainmeter
date_saved: 2026-05-05T09:43:57.834911+00:00
instance: kb-cron
parent: strainmeter-20260505-0
summary:
A strainmeter is an instrument used by geophysicists to measure the deformation of the Earth. Linear strainmeters measure the changes in the distance between two points, using either a solid piece of material (over a short distance) or a laser interferometer (over a long distance, up to several hundred meters). The type using a solid length standard was invented by Benioff in 1932, using an iron pipe; later instruments used rods made of fused quartz. Modern instruments of this type can make measurements of length changes over very small distances, and are commonly placed in boreholes to measure small changes in the diameter of the borehole. Another type of borehole instrument detects changes in a volume filled with fluid (such as silicone oil). The most common type is the dilatometer invented by Sacks and Evertson in the USA (patent 3,635,076); a design that uses specially shaped volumes to measure the strain tensor has been developed by Sakata in Japan. All these types of strainmeters can measure deformation over frequencies from a few Hz to periods of days, months, and years. This allows them to measure signals at lower frequencies than can be detected with seismometers. Most strainmeter records show signals


id: tiltmeter-20260505-0
file: data/en.wikipedia.org/wiki/Tiltmeter-0.md
category: reference
title: Tiltmeter
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Tiltmeter
date_saved: 2026-05-05T09:43:59.000611+00:00
instance: kb-cron
parent: tiltmeter-20260505-0
summary:
A tiltmeter is a sensitive inclinometer designed to measure very small changes from the vertical level, either on the ground or in structures. Tiltmeters are used extensively for monitoring volcanoes, the response of dams to filling, the small movements of potential landslides, the orientation and volume of hydraulic fractures, and the response of structures to various influences such as loading and foundation settlement. Tiltmeters may be purely mechanical or incorporate vibrating-wire or electrolytic sensors for electronic measurement. A sensitive instrument can detect changes of as little as one arc second. Tiltmeters have a long, diverse history, somewhat parallel to the history of the seismometer. The very first tiltmeter was a long-length stationary pendulum. These were used in the very first large concrete dams, and are still in use today, augmented with newer technology such as laser reflectors. Although they had been used for other applications such as volcano monitoring, they have distinct disadvantages, such as their huge length and sensitivity to air currents. Even in dams, they are slowly being replaced by the modern electronic tiltmeter. Volcano and Earth movement monitoring then used the water-tube, long baseline tiltmeter. In 1919, the physicist, Albert A. Michelson, noted that the most favorable


id: wood-anderson-seismometer-20260505-0
file: data/en.wikipedia.org/wiki/Wood–Anderson_seismometer-0.md
category: reference
title: Wood–Anderson seismometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wood–Anderson_seismometer
date_saved: 2026-05-05T09:44:00.145932+00:00
instance: kb-cron
parent: wood-anderson-seismometer-20260505-0
summary:
The Wood–Anderson seismometer (also known as the Wood–Anderson seismograph) is a torsion seismometer developed in the United States by Harry O. Wood and John August Anderson in the 1920s to record local earthquakes in southern California. It photographically records the horizontal motion. The seismometer uses a pendulum of 0.8g, its period is 0.8 seconds, its magnification is 2,800 times, and its damping constant is 0.8. Charles Francis Richter developed the Richter magnitude scale using the Wood–Anderson seismometer. == Overview == In 1908, geologist Grove K. Gilbert paid Harry Wood $1,000 to draft a map of potentially active faults in northern California and several years later Andrew Lawson, professor at the University of California, Berkeley assigned Wood to oversee the University's seismometers, where attention was focused on local earthquakes as well as the distant events that were used (especially by European scientists like Beno Gutenberg) to study the attributes of the Earth's interior. Seismometers that were in use up until that time had been developed and optimized for detecting the long-period seismic waves from distant earthquakes and did not detect local events well. Wood left Berkeley in 1912 and spent several years researching volcano seismology in Hawaii and made contact with


id: adron-rm-20260505-0
file: data/en.wikipedia.org/wiki/ADRON-RM-0.md
category: reference
title: ADRON-RM
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/ADRON-RM
date_saved: 2026-05-05T09:44:02.707682+00:00
instance: kb-cron
parent: adron-rm-20260505-0
summary:
ADRON-RM (Autonomous Detector of Radiation of Neutrons Onboard Rover at Mars) is a neutron spectrometer to search for subsurface water ice and hydrated minerals. This analyser is part of the science payload on board the European Space Agency's Rosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars. The rover is planned to be launched not earlier than 2028 and land on Mars in 2029. ADRON-RM is a near copy of ADRO-EM on the stationary ExoMars 2020 surface platform and the Dynamic Albedo of Neutrons (DAN) neutron detector on board NASA's Curiosity rover, all designed by Igor Mitrofanov from the Russian Space Research Institute (IKI). == Overview == ADRON-RM is a neutron spectrometer that will search for hydrogen in the form of bound water or water ice, and hydrogen-bearing compounds. It will be used in combination with WISDOM instrument (a ground-penetrating radar) to study the subsurface beneath the rover and to search for optimal sites for drilling and sample collection. It can also detect trace elements such as Gd and major elements that constitute soil, such as Cl, Fe, Ti. It will also monitor the neutron component of the radiation background on Mars' surface. == Development == The


id: advanced-technology-microwave-sounder-20260505-0
file: data/en.wikipedia.org/wiki/Advanced_Technology_Microwave_Sounder-0.md
category: reference
title: Advanced Technology Microwave Sounder
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Advanced_Technology_Microwave_Sounder
date_saved: 2026-05-05T09:44:04.496319+00:00
instance: kb-cron
parent: advanced-technology-microwave-sounder-20260505-0
summary:
The Advanced Technology Microwave Sounder (ATMS) is a 22-channel scanning microwave radiometer for observation of the Earth's atmosphere and surface. It is the successor to the Advanced Microwave Sounding Unit (AMSU) on NOAA weather satellites. ATMS units have been flown on the Suomi NPP and on the Joint Polar Satellite System. == Applications == ATMS measurements are assimilated into numerical weather prediction models and atmospheric profiles retrieved by the combination of ATMS and the Cross-track Infrared Sounder on the same satellites are useful for synoptic scale meteorology. Also, ATMS continues the record from its predecessor instruments MSU and AMSU of measurements in the 5-mm band of oxygen for monitoring of atmospheric temperature trends. == Instrument characteristics == All of the channels are contained within one unit, unlike the AMSU which comprises two instruments (AMSU-A and AMSU-B). The radiometer's antenna scans underneath the satellite through nadir, and its polarization vector rotates with the scan angle. The sampling rate satisfies the Nyquist criterion for channels 1-16; thus, images produced from the data are not aliased. However, ATMS images exhibit striping, attributed to receiver gain fluctuations (1/f noise), which can be removed by filtering the data. Table 1 lists some characteristics of the


id: advanced-very-high-resolution-radiometer-20260505-0
file: data/en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer-0.md
category: reference
title: Advanced Very-High-Resolution Radiometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer
date_saved: 2026-05-05T09:44:05.717614+00:00
instance: kb-cron
parent: advanced-very-high-resolution-radiometer-20260505-0
summary:
The Advanced Very-High-Resolution Radiometer (AVHRR) instrument is a space-borne sensor that measures the reflectance of the Earth in five spectral bands that are relatively wide by today's standards. AVHRR instruments are or have been carried by the National Oceanic and Atmospheric Administration (NOAA) family of polar orbiting platforms (POES) and European MetOp satellites. The instrument scans several channels; two are centered on the red (0.6 micrometres) and near-infrared (0.9 micrometres) regions, a third one is located around 3.5 micrometres, and another two the thermal radiation emitted by the planet, around 11 and 12 micrometres. The first AVHRR instrument was a four-channel radiometer. The final version, AVHRR/3, first carried on NOAA-15 launched in May 1998, acquires data in six channels. The AVHRR has been succeeded by the Visible Infrared Imaging Radiometer Suite, carried on the Joint Polar Satellite System spacecraft. == Operation == Prior to 2025, NOAA had at least two polar-orbiting meteorological satellites in orbit at all times, with one satellite crossing the equator in the early morning and early evening and the other crossing the equator in the afternoon and late evening. The primary sensor on board both satellites was the AVHRR instrument. Morning-satellite data were most commonly used


id: advanced-very-high-resolution-radiometer-20260505-1
file: data/en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer-1.md
category: reference
title: Advanced Very-High-Resolution Radiometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer
date_saved: 2026-05-05T09:44:05.717614+00:00
instance: kb-cron
parent: advanced-very-high-resolution-radiometer-20260505-0
summary:
==== Loeb ==== In another similar method using surface targets, Loeb [1997] uses spatiotemporal uniform ice surfaces in Greenland and Antarctica to produce second-order polynomial reflectance calibration curves as a function of solar zenith angle; calibrated NOAA-9 near-nadir reflectances are used to generate the curves that can then derive the calibrations for other AHVRRs in orbit (e.g. NOAA-11, -12, and -14). It was found that the ratio of calibration coefficients derived by Loeb [1997] and Rao and Chen [1995] are independent of solar zenith angle, thus implying that the NOAA-9-derived calibration curves provide an accurate relation between the solar zenith angle and observed reflectance over Greenland and Antarctica. ==== Iwabuchi ==== Iwabuchi [2003] employed a method to calibrate NOAA-11 and -14 that uses clear-sky ocean and stratus cloud reflectance observations in a region of the NW Pacific Ocean and radiative transfer calculations of a theoretical molecular atmosphere to calibrate AVHRR Ch. 1. Using a month of clear-sky observations over the ocean, an initial minimum guess to the calibration slope is made. An iterative method is then used to achieve the optimal slope values for Ch. 1 with slope corrections adjusting for uncertainties in ocean reflectance, water vapor, ozone, and noise.


id: advanced-very-high-resolution-radiometer-20260505-2
file: data/en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer-2.md
category: reference
title: Advanced Very-High-Resolution Radiometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer
date_saved: 2026-05-05T09:44:05.717614+00:00
instance: kb-cron
parent: advanced-very-high-resolution-radiometer-20260505-0
summary:
==== Calibration using the moderate-resolution imaging spectroradiometer ==== Another recent method for the absolute calibration of the AHVRR record makes use of the contemporary MODIS sensor onboard NASA's TERRA and AQUA satellites. The MODIS instrument has high calibration accuracy and can track its own radiometric changes due to the inclusion of an onboard calibration system for the VIS/NIR spectral region [MCST]. The following method utilizes the high accuracy of MODIS to absolutely calibrate AVHRRs via simultaneous nadir overpasses (SNOs) of both MODIS/AVHRR and AVHRR/AVHRR satellite pairs as well as MODIS-characterized surface reflectances for a Libyan Desert target and Dome-C in Antarctica [Heidinger et al., 2010]. Ultimately, each individual calibration event available (MODIS/AVHRR SNO, Dome C, Libyan Desert, or AVHRR/AVHRR SNO) is used to provide a calibration slope time series for a given AVHRR sensor. Heidinger et al. [2010] use a second-order polynomial from a least-squares fit to determine the time series. The first step involves using a radiative transfer model that will convert observed MODIS scenes into those that a perfectly calibrated AVHRR would see. For MODIS/AVHRR SNO occurrences, it was determined that the ratio of AVHRR to MODIS radiances in both Ch1 and Ch2 are modeled well by a


id: advanced-very-high-resolution-radiometer-20260505-3
file: data/en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer-3.md
category: reference
title: Advanced Very-High-Resolution Radiometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Advanced_Very-High-Resolution_Radiometer
date_saved: 2026-05-05T09:44:05.717614+00:00
instance: kb-cron
parent: advanced-very-high-resolution-radiometer-20260505-0
summary:
== Further reading == Frey, C.; Kuenzer, C.; Dech, S. (2012). "Quantitative comparison of the operational NOAA AVHRR LST product of DLR and the MODIS LST product V005". International Journal of Remote Sensing. 33 (22): 7165–7183. Bibcode:2012IJRS...33.7165F. doi:10.1080/01431161.2012.699693. S2CID 128981116. Brest, C.L. and W.B. Rossow. 1992. Radiometric calibration and monitoring of NOAA AVHRR data for ISCCP. International Journal of Remote Sensing. Vol. 13. pp. 235–273. Brest, C.L. et al. 1997. Update of Radiance Calibrations for ISCCP. Journal of Atmospheric and Oceanic Technology. Vol 14. pp. 1091–1109. Cao, C. et al. 2008. Assessing the consistency of AVHRR and MODIS L1B reflectance for generating Fundamental Climate Data Records. Journal of Geophysical Research. Vol. 113. D09114. doi:10.1029/2007JD009363. Halthore, R. et al. 2008. Role of Aerosol Absorption in Satellite Sensor Calibration. IEEE Geoscience and Remote Sensing Letters. Vol. 5. pp. 157–161. Heidinger, A. K. et al. 2002. Using Moderate Resolution Imaging Spectrometer (MODIS) to calibrate Advanced Very High Resolution Radiometer reflectance channels. Journal of Geophysical Research. Vol. 107. doi:10.1029/2001JD002035. Heidinger, A.K. et al. 2010. Deriving an inter-sensor consistent calibration for the AVHRR solar reflectance data record. International Journal of Remote Sensing. Vol. 31. pp. 6493–6517. Iwabuchi, H. 2003. Calibration of the visible and near-infrared


id: alice-spacecraft-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Alice_(spacecraft_instrument)-0.md
category: reference
title: Alice (spacecraft instrument)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alice_(spacecraft_instrument)
date_saved: 2026-05-05T09:44:06.912554+00:00
instance: kb-cron
parent: alice-spacecraft-instrument-20260505-0
summary:
Alice is any one of two ultraviolet imaging spectrometers; one used on the New Horizons spacecraft and the other used on the Rosetta spacecraft. Alice is a small telescope with a spectrograph and a special detector with 32 pixels each with 1024 spectral channels detecting ultraviolet light. Its primary role is to determine the relative concentrations of various elements and isotopes in Pluto's atmosphere. Alice has an off-axis telescope which sends light to a Rowland-circle spectrograph, and the instrument has a field of view of 6 degrees. It is designed to capture airglow and solar occultation at the same time, and has two inputs to allow this. == Overview == Alice uses an array of potassium bromide and caesium iodide type of photocathodes. It detects in the extreme and far ultraviolet spectrum, from 700–2,050 Å (70–205 nm) wavelengths of light, with a spectral resolution of 8–12 Å (0.80–1.20 nm) and a spatial resolution of 500 metres (1,600 feet) per 50 km (31 miles) of altitude. Alice is intended, among its capabilities, to detect ultraviolet signatures of noble (aka inert) gases including helium, neon, argon, and krypton. Alice should also be able to detect water, carbon monoxide, and carbon dioxide in


id: alpha-particle-x-ray-spectrometer-20260505-0
file: data/en.wikipedia.org/wiki/Alpha_particle_X-ray_spectrometer-0.md
category: reference
title: Alpha particle X-ray spectrometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Alpha_particle_X-ray_spectrometer
date_saved: 2026-05-05T09:44:08.100387+00:00
instance: kb-cron
parent: alpha-particle-x-ray-spectrometer-20260505-0
summary:
APXS is also an abbreviation for APache eXtenSion tool, an extension for Apache web servers. An alpha particle X-ray spectrometer (APXS) is a spectrometer that analyses the chemical element composition of a sample from scattered alpha particles and fluorescent X-rays after a sample is irradiated with alpha particles and X-rays from radioactive sources. This method of analysing the elemental composition of a sample is most often used on space missions, which require low weight, small size, and minimal power consumption. Other methods (e.g. mass spectrometry) are faster, and do not require the use of radioactive materials, but require larger equipment with greater power requirements. A variation is the alpha proton X-ray spectrometer, such as on the Pathfinder mission, which also detects protons. Over the years several modified versions of this type of instrument such as APS (without X-ray spectrometer) or APXS have been flown: Surveyor 5-7, Mars Pathfinder, Mars 96, Mars Exploration Rover, Phobos, Mars Science Laboratory, the Philae comet lander and the Chandrayaan-3 lunar rover. APS/APXS devices will be included on several upcoming missions. == Sources == Several forms of radiation are used in APXS. They include alpha particles, protons, and X-rays. Alpha particles, protons, and X-rays are emitted


id: atmosphere-space-interactions-monitor-20260505-0
file: data/en.wikipedia.org/wiki/Atmosphere-Space_Interactions_Monitor-0.md
category: reference
title: Atmosphere-Space Interactions Monitor
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atmosphere-Space_Interactions_Monitor
date_saved: 2026-05-05T09:44:09.250846+00:00
instance: kb-cron
parent: atmosphere-space-interactions-monitor-20260505-0
summary:
Atmosphere-Space Interactions Monitor (ASIM) is a project led by the European Space Agency to place cameras and X-ray/γ-ray detectors on the International Space Station to observe the upper atmosphere in order to study sprites, jets and elves and terrestrial gamma-ray flashes in connection with thunderstorms. It is hoped that measurements of these phenomena from space will contribute to the understanding of Earth's upper atmosphere. The ASIM components, originally planned to be completed in 2014, were launched on 2 April 2018 and mounted on the Columbus External Payload Facility on 13 April 2018. Danish tech company Terma A/S is running the technical part of the project for ESA and DTU Space (National Space Institute) from the Technical University of Denmark provides the scientific leadership of the project. Mission operations will be performed by the Belgian User Support and Operations Centre (B.USOC) in Uccle, Belgium. First results from the measurements revealed that gamma ray bursts form when powerful electric fields course through the atmosphere, just before a lightning bolt travels along the same path. These results were published in July 2019. == Instruments == The ASIM payload has a mass of 314 kg (692 lb) and consists of sub-systems CEPA and DHPU,


id: atmospheric-chemistry-suite-20260505-0
file: data/en.wikipedia.org/wiki/Atmospheric_Chemistry_Suite-0.md
category: reference
title: Atmospheric Chemistry Suite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atmospheric_Chemistry_Suite
date_saved: 2026-05-05T09:44:10.564246+00:00
instance: kb-cron
parent: atmospheric-chemistry-suite-20260505-0
summary:
The Atmospheric Chemistry Suite (ACS) is a science payload consisting of three infrared spectrometer channels aboard the ExoMars Trace Gas Orbiter (TGO) orbiting Mars since October 2016. The three channels are: the near-infrared channel (NIR), the mid-infrared channel (MIR), and the far infrared channel (FIR, also called TIRVIM). The ACS was proposed in 2011 by Russian Academy Section and eventually accepted by the European Space Agency (ESA) and Roscosmos as one of two Russian instruments onboard TGO. The instrument was funded by Roscosmos and Centre national d'études spatiales (CNES) of France, and has components of both Russia and France. Its development and fabrication was under Russian leadership. The functionality of all the three channels was confirmed during cruise to Mars. == Objectives == The main objective of the ACS suite is to make an inventory and map minor atmospheric species or trace gases in the atmosphere of Mars. This will allow scientists to profile the upper limits on the methane contents, and to possibly to detect sulfur dioxide (SO2), a gas of volcanic origin. == Channels == The near-infrared channel (NIR), is a compact spectrometer operating in the range of 0.7–1.7 μm with a resolving power of λ/Δλ ~ 20,000


id: atmospheric-infrared-sounder-20260505-0
file: data/en.wikipedia.org/wiki/Atmospheric_infrared_sounder-0.md
category: reference
title: Atmospheric infrared sounder
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Atmospheric_infrared_sounder
date_saved: 2026-05-05T09:44:11.758008+00:00
instance: kb-cron
parent: atmospheric-infrared-sounder-20260505-0
summary:
The atmospheric infrared sounder (AIRS) is one of six instruments flying on board NASA's Aqua satellite, launched on May 4, 2002. The instrument is designed to support climate research and improve weather forecasting. Working in combination with its partner microwave instrument, the Advanced Microwave Sounding Unit (AMSU-A), AIRS observes the global water and energy cycles, climate variation and trends, and the response of the climate system to increased greenhouse gases. AIRS uses infrared technology to create three-dimensional maps of air and surface temperature, water vapor, and cloud properties. AIRS can also measure trace greenhouse gases such as ozone, carbon monoxide, carbon dioxide, and methane. AIRS and AMSU-A share the Aqua satellite with the Moderate Resolution Imaging Spectroradiometer (MODIS), Clouds and the Earth's Radiant Energy System (CERES), and the Advanced Microwave Scanning Radiometer-EOS (AMSR-E). Aqua is part of NASA's "A-train," a series of high-inclination, Sun-synchronous satellites in low Earth orbit designed to make long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and ocean. AIRS data are free and available to the public through the Goddard Earth Sciences Data Information and Services Center. NASA's Jet Propulsion Laboratory in Pasadena, California, manages AIRS for NASA's Science Mission Directorate in Washington,


id: automatic-picture-transmission-20260505-0
file: data/en.wikipedia.org/wiki/Automatic_picture_transmission-0.md
category: reference
title: Automatic picture transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Automatic_picture_transmission
date_saved: 2026-05-05T09:44:12.925851+00:00
instance: kb-cron
parent: automatic-picture-transmission-20260505-0
summary:
The Automatic Picture Transmission (APT) system is an analog image transmission system developed for use on weather satellites. It was introduced in the 1960s and over four decades has provided image data to relatively low-cost user stations at locations in most countries of the world. A user station anywhere in the world can receive local data at least twice a day from each satellite as it passes nearly overhead. == Transmission == === Structure === The broadcast transmission is composed of two image channels, telemetry information, and synchronization data, with the image channels typically referred to as Video A and Video B. All this data is transmitted as a horizontal scan line. A complete line is 2080 pixels long, with each image using 909 pixels and the remainder going to the telemetry and synchronization. Lines are transmitted at 2 per second, which equates to a 4160 words per second, or 4160 baud. === Images === On NOAA POES system satellites, the two images are 4 km / pixel smoothed 8-bit images derived from two channels of the advanced very-high-resolution radiometer (AVHRR) sensor. The images are corrected for nearly constant geometric resolution prior to being broadcast; as such, the images are


id: automatic-picture-transmission-20260505-1
file: data/en.wikipedia.org/wiki/Automatic_picture_transmission-1.md
category: reference
title: Automatic picture transmission
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Automatic_picture_transmission
date_saved: 2026-05-05T09:44:12.925851+00:00
instance: kb-cron
parent: automatic-picture-transmission-20260505-0
summary:
=== Displaying the images === Years ago, to receive APT images, a specialized decoder was required in addition to the receiver to display or print images, much like HF WEFAX (serving the maritime community). Often both receiver and decoder were combined into one unit. Nowadays, with the advent of personal computers, all that is required is dedicated software such as WXtoIMG (many of which offer "free" versions [1]) and a sound card. The sound card acquires and digitizes the slow scan video (in the audible range) coming from the speaker, phones, or line-out of the receiver, and then the software will process the various visible and infrared channels of the AVHRR sensor. ==== Enhanced images ==== Since each channel of the AVHRR sensor is sensitive to only one wavelength of light, each of the two images is luminance only, also known as grayscale. However, different materials tend to emit or reflect with a consistent relative intensity. This has enabled the development of software that can apply a color palette to the images which simulates visible light coloring. If the decoding software knows exactly where the satellite was, it can also overlay outlines and boundaries to help in utilizing the resulting


id: cachecam-20260505-0
file: data/en.wikipedia.org/wiki/Cachecam-0.md
category: reference
title: Cachecam
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cachecam
date_saved: 2026-05-05T09:44:14.125067+00:00
instance: kb-cron
parent: cachecam-20260505-0
summary:
The Cachecam, a photographic camera, is mounted inside the rover underbelly, at the top of the sample cache of NASA's Perseverance rover mission to Mars. == Overview == The Cachecam's main job is to photograph the top of a sample tube after the sample is gathered in order to verify acquisition before the tube is sealed. It may also take images at other points in the sample processing. The Cachecam will acquire color images of the samples using its 20 megapixel CMOS detector. It is considered an engineering camera. The other sets of engineering cameras on the Mars 2020 Rover are the Navcams and hazcams. == See also == Astrionics List of NASA cameras on spacecraft Mars rover == References == == External links == The Cameras on the Mars 2020 Rover


id: chemistry-and-camera-complex-20260505-0
file: data/en.wikipedia.org/wiki/Chemistry_and_Camera_complex-0.md
category: reference
title: Chemistry and Camera complex
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemistry_and_Camera_complex
date_saved: 2026-05-05T09:44:15.324222+00:00
instance: kb-cron
parent: chemistry-and-camera-complex-20260505-0
summary:
Chemistry and Camera complex (ChemCam) is a suite of remote sensing instruments on Mars for the Curiosity rover. As the name implies, ChemCam is actually two different instruments combined as one: a laser-induced breakdown spectroscopy (LIBS) and a Remote Micro Imager (RMI) telescope. The purpose of the LIBS instrument is to provide elemental compositions of rock and soil, while the RMI will give ChemCam scientists high-resolution images of the sampling areas of the rocks and soil that LIBS targets. The LIBS instrument can target a rock or soil sample from up to 7 m (23 ft) away, vaporizing a small amount of it with about 30 5-nanosecond pulses from a 1067 nm infrared laser and then observing the spectrum of the light emitted by the vaporized rock. == Overview == ChemCam has the ability to record up to 6,144 different wavelengths of ultraviolet, visible, and infrared light. Detection of the ball of luminous plasma is done in the visible, near-UV and near-infrared ranges, between 240 nm and 800 nm. The first initial laser testing of the ChemCam by Curiosity on Mars was performed on a rock, N165 ("Coronation" rock), near Bradbury Landing on August 19, 2012. Using the same collection


id: cleo-router-20260505-0
file: data/en.wikipedia.org/wiki/CLEO_(router)-0.md
category: reference
title: CLEO (router)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/CLEO_(router)
date_saved: 2026-05-05T09:44:30.318956+00:00
instance: kb-cron
parent: cleo-router-20260505-0
summary:
CLEO, the Cisco router in Low Earth Orbit, is an Internet router from Cisco Systems that was integrated into the UK-DMC Disaster Monitoring Constellation satellite built by Surrey Satellite Technology Ltd (SSTL) as a secondary experimental hosted payload, and launched into space with the satellite and sister satellites on a Kosmos 3M rocket from Plesetsk on 27 September 2003. CLEO and the UK-DMC satellite were tested over five years to show the feasibility of extending the Internet to orbit, using both the Internet Protocol and Mobile IP. CLEO was configured by NASA's Glenn Research Center to be used with Virtual Mission Operations Center (VMOC) software from General Dynamics as part of a large internetworking exercise from the field at Vandenberg Air Force Base in June 2004. On 29 March 2007, CLEO was configured for and tested on IPsec and IPv6 use, making this the first use of IPv6 on board a satellite in orbit. The use of CLEO builds on and validates the approach to use of the Internet Protocol articulated by Keith Hogie with NASA Goddard and first demonstrated as part of the Operating Missions as Nodes on the Internet (OMNI) effort on board the UoSAT-12 satellite built by


id: consert-20260505-0
file: data/en.wikipedia.org/wiki/CONSERT-0.md
category: reference
title: CONSERT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/CONSERT
date_saved: 2026-05-05T09:44:31.535643+00:00
instance: kb-cron
parent: consert-20260505-0
summary:
CONSERT (COmet Nucleus Sounding Experiment by Radiowave Transmission) is a scientific experiment on board the European Space Agency's Rosetta mission, launched in 2004, to provide information about the deep interior of the comet 67P/Churyumov-Gerasimenko upon the probe's rendezvous with the comet in 2014. The CONSERT radar was to perform tomography of the nucleus by measuring electromagnetic wave propagation from the Philae lander and the Rosetta orbiter throughout the comet nucleus in order to determine its internal structures and to deduce information on its composition. The related lander and orbiter electronics were provided by France and both antennas were constructed in Germany. The experiment was designed and built in France by Laboratoire de Planétologie de Grenoble (LPG now IPAG) and by Service d'Aéronomie in Paris (SA now LATMOS), in Germany by the Max Planck Institute for Solar System Research (MPS) in Göttingen. The Principal Investigator of CONSERT is Dr. Wlodek Kofman (IPAG), Director of Research at CNRS. On 13 November 2014, the experiment unexpectedly provided information to locate Philae after it had bounced into an unknown place. == Scientific objectives == The scientific objectives of the CONSERT experiment are the determination of the main dielectric properties and, through modelling, to set


id: cosmic-dust-analyzer-20260505-0
file: data/en.wikipedia.org/wiki/Cosmic_Dust_Analyzer-0.md
category: reference
title: Cosmic Dust Analyzer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cosmic_Dust_Analyzer
date_saved: 2026-05-05T09:44:32.786321+00:00
instance: kb-cron
parent: cosmic-dust-analyzer-20260505-0
summary:
The Cosmic Dust Analyzer (CDA) was a large-area (0.1 m2 total sensitive area) multi-sensor dust instrument included on the Cassini spacecraft, which was launched in 1997 and orbited Saturn from 2004 to 2017. The instrument included a chemical dust analyzer (time-of-flight mass spectrometer), a highly reliable impact ionization detector, and two high rate polarized polyvinylidene fluoride (PVDF) detectors. Over 7 years en route to Saturn, the CDA analysed the interplanetary dust cloud, the stream of interstellar dust, and Jupiter dust streams. During 13 years in orbit around Saturn, the CDA studied the E ring, dust in the plumes of Enceladus, and dust in Saturn's environment. == Overview == The Cosmic Dust Analyzer was the seventh dust instrument from the Max Planck Institute for Nuclear Physics (MPIK), Heidelberg (Germany) following the dust detectors on the HEOS 2 satellite and dust detectors on the Galileo and Ulysses space probes and the more complex dust analyzers on the Helios spacecraft, the Giotto and VeGa spacecraft to Halley's Comet. The new dust analyzer system was developed by a team of scientists led by Eberhard Grün and engineers led by Dietmar Linkert to analyze dust in the Saturn system on board the Cassini spacecraft. This


id: cosmic-ray-subsystem-20260505-0
file: data/en.wikipedia.org/wiki/Cosmic_Ray_Subsystem-0.md
category: reference
title: Cosmic Ray Subsystem
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cosmic_Ray_Subsystem
date_saved: 2026-05-05T09:44:34.007122+00:00
instance: kb-cron
parent: cosmic-ray-subsystem-20260505-0
summary:
Cosmic Ray Subsystem (CRS, or Cosmic Ray System) is an instrument aboard the Voyager 1 and Voyager 2 spacecraft of the NASA Voyager program, and it is an experiment to detect cosmic rays. The CRS includes a High-Energy Telescope System (HETS), Low-Energy Telescope System (LETS), and The Electron Telescope (TET). It is designed to detect energetic particles and some of the requirements were for the instrument to be reliable and to have enough charge resolution. It can also detect the energetic particles like protons from the Galaxy or Earth's Sun. As of 2019, CRS is one of the active remaining instruments on both Voyager spacecraft. It is described by as being able to detect electrons from 3–110 MeV and cosmic ray nuclei 1–500 MeV/n. All three systems used solid-state detectors. CRS is one of the five fields and particle experiments on each spacecraft. One of the goals is to gain a deeper understanding of the solar wind. Other objects of study including electrons and nuclei from planetary magnetospheres and from outside the Solar System. In the summer of 2019, the heater for the CRS on Voyager 2 was turned off to save power; however, although it cooled off, it was


id: diviner-radiometer-20260505-0
file: data/en.wikipedia.org/wiki/Diviner_(radiometer)-0.md
category: reference
title: Diviner (radiometer)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Diviner_(radiometer)
date_saved: 2026-05-05T09:44:35.175772+00:00
instance: kb-cron
parent: diviner-radiometer-20260505-0
summary:
Diviner, also referred to as the Diviner Lunar Radiometer Experiment (DLRE), is an infrared radiometer aboard NASA's Lunar Reconnaissance Orbiter, part of the Lunar Precursor Robotic Program which is studying the Moon. It has been used to create temperature maps of the Moon's surface, as well as detect ice deposits and surface composition. The instrument has measured temperatures of −247 °C (−412.6 °F) in a crater at the northern pole and −238 °C (−396.4 °F) in craters at the southern pole. On 9 October 2009, the Diviner team announced the detection of a hot spot on the Moon at the location of the LCROSS spacecraft impact site. == References == == External links == Diviner Lunar Radiometer Experiment at UCLA


id: doris-satellite-system-20260505-0
file: data/en.wikipedia.org/wiki/DORIS_(satellite_system)-0.md
category: reference
title: DORIS (satellite system)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/DORIS_(satellite_system)
date_saved: 2026-05-05T09:44:36.342174+00:00
instance: kb-cron
parent: doris-satellite-system-20260505-0
summary:
DORIS is a French satellite system used for the determination of satellite orbits (e.g. TOPEX/Poseidon) and for positioning. The name is an acronym of "Doppler Orbitography and Radiopositioning Integrated by Satellite" or, in French, Détermination d'Orbite et Radiopositionnement Intégré par Satellite. == Principle == Ground-based radio beacons emit a signal which is picked up by receiving satellites. This is in reverse configuration to other GNSS, in which the transmitters are space-borne and receivers are in majority near the surface of the Earth. A frequency shift of the signal occurs that is caused by the movement of the satellite (Doppler effect). From this observation satellite orbits, ground positions, as well as other parameters can be derived. == Organization == DORIS is a French system which was initiated and is maintained by the French Space Agency (CNES). It is operated from Toulouse. == Ground segment == The ground segment includes about 50-60 ground stations, equally distributed over the Earth and ensure a good coverage for orbit determination. For the installation of a beacon only electricity is required because the station only emits a signal but does not receive any information. DORIS beacons transmit to the satellites on two UHF frequencies, 401.25 MHz


id: dual-segmented-langmuir-probe-20260505-0
file: data/en.wikipedia.org/wiki/Dual_segmented_Langmuir_probe-0.md
category: reference
title: Dual segmented Langmuir probe
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dual_segmented_Langmuir_probe
date_saved: 2026-05-05T09:44:37.548960+00:00
instance: kb-cron
parent: dual-segmented-langmuir-probe-20260505-0
summary:
Dual Segmented Langmuir Probe (DSLP) is an instrument developed primarily by Czech researchers and engineers to study the magnetospheric background plasma flown on board the spacecraft of the European Space Agency (ESA) Proba 2. Data acquired by DSLP will be used to reach these specific scientific goals: Directional Measurements: Contrary to classical Langmuir probes, the new DSLP concept of data acquisition from the independent segments will enable to study also plasma characteristics in different directions. This should provide for example estimations of plasma flow velocity. Typically in the presence of magnetic field, electron temperatures are observed to be slightly different in the direction parallel and perpendicular to the magnetic field lines. This temperature anisotropy should be measured with DSLP by way of directional data acquisition. Non-Maxwellian Features in Ionospheric Plasma: Classical theories for LPs are typically developed for plasmas in a thermodynamic equilibrium, that is for particle populations possessing Maxwellian velocity distribution functions. However, a thermodynamic equilibrium and thus a Maxwellian distribution is an idealized case while the real distribution in many plasma environments often exhibits various non-Maxwellian features, like loss-cone or flat-top distributions or high-energy tails. We intend to adapt the DSLP theoretical model in order to see whether


id: dynamic-albedo-of-neutrons-20260505-0
file: data/en.wikipedia.org/wiki/Dynamic_Albedo_of_Neutrons-0.md
category: reference
title: Dynamic Albedo of Neutrons
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Dynamic_Albedo_of_Neutrons
date_saved: 2026-05-05T09:44:38.794422+00:00
instance: kb-cron
parent: dynamic-albedo-of-neutrons-20260505-0
summary:
The Dynamic Albedo of Neutrons (DAN) instrument is an experiment mounted on the Mars Science Laboratory's Curiosity rover. It is a pulsed sealed-tube neutron source and detector used to measure hydrogen or ice and water at or near the Martian surface. The instrument consists of the detector element (DE) and a 14.1 MeV pulsing neutron generator (PNG). The die-away time of neutrons is measured by the DE after each neutron pulse from the PNG. DAN was provided by the Russian Federal Space Agency, funded by Russia and is under the leadership of Principal Investigator Igor Mitrofanov. == History == On August 18, 2012 (sol 12), DAN was turned on, marking the success of a Russian-American collaboration on the surface of Mars and the first working Russian science instrument on the Martian surface since Mars 3 stopped transmitting over forty years ago. The instrument is designed to detect subsurface water. On March 18, 2013 (sol 218), NASA reported evidence of mineral hydration, likely hydrated calcium sulfate, in several rock samples including the broken fragments of "Tintina" rock and "Sutton Inlier" rock as well as in veins and nodules in other rocks like "Knorr" rock and "Wernicke" rock. Analysis using the rover's


id: enceladus-icy-jet-analyzer-20260505-0
file: data/en.wikipedia.org/wiki/Enceladus_Icy_Jet_Analyzer-0.md
category: reference
title: Enceladus Icy Jet Analyzer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Enceladus_Icy_Jet_Analyzer
date_saved: 2026-05-05T09:44:40.032692+00:00
instance: kb-cron
parent: enceladus-icy-jet-analyzer-20260505-0
summary:
The Enceladus Icy Jet Analyzer (ENIJA) is a time-of-flight mass spectrometer developed to search for prebiotic molecules like amino acids and biosignatures in the plumes of Saturn's moon Enceladus. Most of the ice particles in Enceladus's plume have been shown to be direct samples of subsurface waters, offering an opportunity to assess its internal ocean's geochemical and habitability potential without having to land and drill through the ice. The ENIJA instrument has been formally proposed to fly on two missions: the Enceladus Life Finder (ELF), and on the Explorer of Enceladus and Titan (E2T). == Description == The instrument is based on the principle of impact ionization and is optimized for the analysis of high dust fluxes and number densities as typically occur during Enceladus plume crossings. Impact ionization shows an excellent sensitivity for compounds embedded in a water ice matrix. Ice particles as small as 0.1 μm at an impact speed of 5 km/s can be analyzed. The mass resolution is > 970 m/dm for typical plume particles in the size range 0.01 to 100 μm. Detection of elemental and molecular species over such a wide mass range permits clear characterization of particle chemistry, simultaneously covering individual ions like


id: europa-clipper-magnetometer-20260505-0
file: data/en.wikipedia.org/wiki/Europa_Clipper_Magnetometer-0.md
category: reference
title: Europa Clipper Magnetometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Europa_Clipper_Magnetometer
date_saved: 2026-05-05T09:44:41.220992+00:00
instance: kb-cron
parent: europa-clipper-magnetometer-20260505-0
summary:
The Europa Clipper Magnetometer (ECM) is a spacecraft magnetometer aboard the planned Europa Clipper mission. It will be used to precisely measure Europa's magnetic field during consecutive fly-bys, allowing scientists to potentially confirm the existence of Europa's hypothesised subsurface ocean. If this ocean exists, the instrument will be able to determine its depth and salinity, as well as the thickness of the moon's icy shell. The magnetometer team is led by Margaret Kivelson, with Xianzhe Jia serving as deputy team leader. == Overview == The ECM is a highly sensitive and precise magnetometer used to measure small changes in the characteristics of Europa's magnetic field, studying how they vary according to time and location. The instrument will be stowed in a canister at launch, and will have a total of three flux-gate sensors attached to it. It will deploy to its full length of 8.5 meters (25 feet) in the days after launch. The spacecraft contains over 300 individual sources of magnetic interference, such as magnets in the propulsion valves, and current loops in the solar arrays. As a result, the instrument will be mounted on an 8.5 meter boom to reduce the effect of this contamination, but will still


id: europa-ultraviolet-spectrograph-20260505-0
file: data/en.wikipedia.org/wiki/Europa_Ultraviolet_Spectrograph-0.md
category: reference
title: Europa Ultraviolet Spectrograph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Europa_Ultraviolet_Spectrograph
date_saved: 2026-05-05T09:44:42.368285+00:00
instance: kb-cron
parent: europa-ultraviolet-spectrograph-20260505-0
summary:
The Europa Ultraviolet Spectrograph (Europa-UVS) is an ultraviolet spectrograph imager that will be flown on board the Europa Clipper mission to Jupiter's moon Europa. The Europa-UVS will be able to detect small erupting plumes and will provide data about the composition and dynamics of Europa's thin exosphere. The Principal Investigator is Kurt Retherford of the Southwest Research Institute (SwRI), and the instrument engineer is Laura Jones-Wilson from JPL. == Overview == The Europa Ultraviolet Spectrograph inherits technology from a series of successful ultraviolet imaging spectrographs (Rosetta-Alice, New Horizons-Alice, LRO-LAMP, Juno-UVS and JUICE-UVS). Europa-UVS observes photons in the 55-210 nm wavelength range, along a 7.5° slit. A radiation-hardened integrated circuit will be incorporated to meet the radiation requirements. The Europa-UVS offers additional capabilities to locate and characterize plumes erupting from Europa's surface. UVS will also investigate the composition and chemistry of Europa's atmosphere, its surface, and study how energy and mass flow around the moon and its environment. The instrument is a sensitive imaging spectrograph that can observe in the ultraviolet spectral range of 55 nm to 210 nm and can achieve a spectral resolution of <0.6 nm. The instrument does not contain a scan mirror, so the spacecraft must provide


id: fields-20260505-0
file: data/en.wikipedia.org/wiki/FIELDS-0.md
category: reference
title: FIELDS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/FIELDS
date_saved: 2026-05-05T09:44:43.570266+00:00
instance: kb-cron
parent: fields-20260505-0
summary:
FIELDS is a science instrument on the Parker Solar Probe (PSP), designed to measure magnetic fields in the solar corona during its mission to study the Sun. It is one of four major investigations on board PSP, along with WISPR, ISOIS, and SWEAP. It features three magnetometers. FIELDS is planned to help answer an enduring questions about the Sun, such as why the solar corona is so hot compared to the surface of the Sun and why the solar wind is so fast (a million miles per hour). The host spacecraft, Parker Solar Probe, was launched by a Delta IV Heavy on August 12, 2018 from Florida, USA. On August 13, 2018 FIELDS became the first instrument to be activated including beginning deployment of the four whip antennas (clamps unlocked) and extension of the magnetometer boom. On September 4, 2018 the whip antennas were deployed. == Overview == FIELDS features three magnetometers: two are fluxgate magnetometers, and the third is a search-coil magnetometer. It has five voltage sensors, four of which extend beyond the spacecraft's heatshield and must directly endure the intense conditions at the planned distances of less than 10 solar radii to the Sun. For best scientific observations,


id: foxsi-sounding-rocket-20260505-0
file: data/en.wikipedia.org/wiki/FOXSI_Sounding_Rocket-0.md
category: reference
title: FOXSI Sounding Rocket
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/FOXSI_Sounding_Rocket
date_saved: 2026-05-05T09:44:44.693883+00:00
instance: kb-cron
parent: foxsi-sounding-rocket-20260505-0
summary:
The Focusing Optics X-ray Solar Imager, or FOXSI, is a sounding rocket payload built by UC Berkeley and led by Säm Krucker to test high energy grazing-incidence focusing optics paired with solid-state pixelated detectors to observe the Sun. FOXSI is composed of seven identical Wolter-I telescope modules, as well as Silicon and Cadmium Telluride strip detectors originally developed for the HXT telescope on the Japanese Hitomi mission. The FOXSI payload flew two times, most recently in 2014 and previously in 2012, on the Black Brant IX sounding rocket. Like most sounding rockets, FOXSI flew for approximately 15 minutes per mission and observed the Sun for about 5 minutes while in space. During its first flight, FOXSI successfully imaged a solar microflare in the hard x-ray band for the first time. FOXSI's third mission, led by Lindsay Glesener of the University of Minnesota, had a successful launch on September 7, 2018, from White Sands, New Mexico. This iteration of the payload included a combination of Silicon and improved Cadmium Telluride detectors, as well as one CMOS soft x-ray detector. Two of the telescope modules were updated from 7-shell to 10-shell configurations, and the payload also introduced collimator technology to reduce the


id: galileo-and-ulysses-dust-detectors-20260505-0
file: data/en.wikipedia.org/wiki/Galileo_and_Ulysses_Dust_Detectors-0.md
category: reference
title: Galileo and Ulysses Dust Detectors
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Galileo_and_Ulysses_Dust_Detectors
date_saved: 2026-05-05T09:44:45.895848+00:00
instance: kb-cron
parent: galileo-and-ulysses-dust-detectors-20260505-0
summary:
The Galileo and Ulysses Dust Detectors are almost identical dust instruments on the Galileo and Ulysses missions. The instruments are large-area (0.1 m2 sensitive area) highly reliable impact ionization detectors of sub-micron and micron sized dust particles. With these instruments the interplanetary dust cloud was characterized between Venus’ and Jupiter's orbits and over the solar poles. A stream of interstellar dust passing through the planetary system was discovered. Close to and inside the Jupiter system streams nanometer sized dust particles that were emitted from volcanoes on Jupiter's moon Io and ejecta clouds around the Galilean moons were discovered and characterized. == Overview == Following the first dust instruments from the Max Planck Institute for Nuclear Physics (MPIK), Heidelberg (Germany) on the HEOS 2 satellite and the Helios spacecraft a new dust instrument was developed by a Team of Scientists and Engineers of Eberhard Grün to detect cosmic dust in the outer planetary system. This instrument had 10 times larger sensitive area (0.1 m2) and employed a multiple coincidence of impact signals in order to cope with the low fluxes of cosmic dust and the hostile environment in the outer planets magnetospheres. The Galileo and Ulysses dust detectors use impact ionization


id: gamma-ray-spectrometer-2001-mars-odyssey-20260505-0
file: data/en.wikipedia.org/wiki/Gamma_Ray_Spectrometer_(2001_Mars_Odyssey)-0.md
category: reference
title: Gamma Ray Spectrometer (2001 Mars Odyssey)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Gamma_Ray_Spectrometer_(2001_Mars_Odyssey)
date_saved: 2026-05-05T09:44:47.060034+00:00
instance: kb-cron
parent: gamma-ray-spectrometer-2001-mars-odyssey-20260505-0
summary:
The Gamma Ray Spectrometer (GRS) is a gamma-ray spectrometer on the 2001 Mars Odyssey spacecraft, a space probe orbiting the planet Mars since 2001. Part of NASA's Mars Surveyor 2001 program, it returns geological data about Mars's surface such as identifying elements and the location of water. It is maintained by the Lunar and Planetary Laboratory at the University of Arizona in the United States. This instrument has mapped the distribution surface hydrogen, thought to trace water in the surface layer of Martian soil. == GRS specifications == The Gamma Ray Spectrometer weighs 30.5 kilograms (67 lb) and uses 32 watts of power. Along with its cooler, it measures 468 by 534 by 604 millimetres (18.4 by 21.0 by 23.8 in). The detector is a photodiode made of a 1.2-kilogram (2.6 lb) germanium crystal, reverse biased to about 3 kilovolts, mounted at the end of a 6-metre (20 ft) boom to minimize interferences from the gamma radiation produced by the spacecraft itself. Its spatial resolution is about 300 kilometres (190 mi). The neutron spectrometer is 173 by 144 by 314 millimetres (6.8 by 5.7 by 12.4 in). The high-energy neutron detector measures 303 by 248 by 242 millimetres (11.9 by


id: geostationary-carbon-cycle-observatory-20260505-0
file: data/en.wikipedia.org/wiki/Geostationary_Carbon_Cycle_Observatory-0.md
category: reference
title: Geostationary Carbon Cycle Observatory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Geostationary_Carbon_Cycle_Observatory
date_saved: 2026-05-05T09:44:48.413911+00:00
instance: kb-cron
parent: geostationary-carbon-cycle-observatory-20260505-0
summary:
Geostationary Carbon Cycle Observatory (GeoCarb or GeoCARB) was an intended NASA Venture-class Earth observation mission that was designed to measure the carbon cycle, building off the success of OCO-2, but in geostationary orbit. GeoCarb was to be stationed over the Americas and make observations between 50° North and South latitudes in geostationary Earth orbit 35,786 km above the equator. Its primary mission was to conduct observations of vegetation health and stress by measuring solar-induced fluorescence, as well as observe the processes that govern the movement of greenhouse gases in the carbon cycle. Selected by NASA in 2016. It was originally intended to be mounted on a commercial geostationary communication satellite operated by SES S.A., but instead NASA, in February 2022, sought a standalone spacecraft to carry GeoCarb. On 28 November 2022, NASA announced the cancellation of development of the GeoCarb mission, citing cost overruns, technical concerns, and the availability of other options to measure and observe greenhouse gases, like the EMIT instrument on the ISS and the upcoming Earth System Observatory. NASA worked with the University of Oklahoa to close the project which was scheduled to be launched around the end of June 2025. GeoCarb was a joint collaboration between


id: geostationary-earth-radiation-budget-20260505-0
file: data/en.wikipedia.org/wiki/Geostationary_Earth_Radiation_Budget-0.md
category: reference
title: Geostationary Earth Radiation Budget
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Geostationary_Earth_Radiation_Budget
date_saved: 2026-05-05T09:44:49.626063+00:00
instance: kb-cron
parent: geostationary-earth-radiation-budget-20260505-0
summary:
The Geostationary Earth Radiation Budget (GERB) is an instrument aboard EUMETSAT's Meteosat Second Generation geostationary satellites designed to make accurate measurements of the Earth radiation budget. It was produced by a European consortium consisting of the United Kingdom, Belgium and Italy. The first, known as GERB 2, was launched on 28 August 2002 on an Ariane 5 rocket. The second, GERB 1, was launched on 21 December 2005, and the third, GERB3, on 5 July 2012. The last GERB 4 device was launched 14 July 2015. The first launched GERB 2 on MSG 1 is currently situated over the Indian Ocean at 41.5°E, while GERBs 1 and 3 on MSG 2 and 3 are still located over the standard Africa EUMETSAT position. GERB 4 on MSG is yet to become operational. == Scientific motivations and objectives == The unprecedented rate of atmospheric CO2 increase occurring since the Industrial Revolution due to human activity is of much concern to scientists as it has occurred an order of magnitude faster than planet Earth has ever experienced. Climate models described as Global Circulation Models (GCMs) are currently avenue to investigate and try and predict how Earth climate will change in response such an


id: geostationary-earth-radiation-budget-20260505-1
file: data/en.wikipedia.org/wiki/Geostationary_Earth_Radiation_Budget-1.md
category: reference
title: Geostationary Earth Radiation Budget
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Geostationary_Earth_Radiation_Budget
date_saved: 2026-05-05T09:44:49.626063+00:00
instance: kb-cron
parent: geostationary-earth-radiation-budget-20260505-0
summary:
== GERB device and calibration == The GERB project is led by the Space and Atmospheric Group (SPAT) based at Imperial College UK, with Professor John. E. Harries the original Principal Investigator and now succeeded by Dr Helen Brindley. The devices themselves were constructed by Rutherford Appleton Laboratory using an Italian 3 mirror silver telescope and electronics designed by the Space Science center at the University of Leicester UK. Each of the four completed GERB devices underwent extensive ground radiometric calibration in a Vacuum Calibration Chamber (VCC) at the Earth Observation and Characterization Facility (EOCF) also the Imperial College and designed by Ray Wrigley. Such tests included confirmation of linearity, LW radiometric gain determination using Warm and Cold BlackBodies (WBB & CBB), SW gain determination using Visible Calibration Source (VISCS) lamp and spot checks on the system level spectral response. Each GERB device makes use of a linear array of blackened thermopile detectors manufactured by Honeywell, which stare at the Earth on each 100rpm rotation of the MSG platform by making use of a De-Scan Mirror (DSM). Hence a column of the Earth disk is taken on each revolution allowing 250x256 Total channel samples followed by 250x256 SW samples with


id: global-ecosystem-dynamics-investigation-20260505-0
file: data/en.wikipedia.org/wiki/Global_Ecosystem_Dynamics_Investigation-0.md
category: reference
title: Global Ecosystem Dynamics Investigation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Global_Ecosystem_Dynamics_Investigation
date_saved: 2026-05-05T09:44:50.820843+00:00
instance: kb-cron
parent: global-ecosystem-dynamics-investigation-20260505-0
summary:
Global Ecosystem Dynamics Investigation (GEDI, pronounced ) is a LiDAR altimeter mission by NASA to measure how deforestation has contributed to atmospheric CO2 concentrations. A full-waveform LiDAR was attached to the International Space Station to provide the first global, high-resolution observations of forest vertical structure. This will allow scientists to map habitats and biomass, particularly in the tropics, providing detail on the Earth's carbon cycle. Although GEDI has been originally developed to monitor biomass and carbon cycle, other potentials have been also investigated such as inland water level monitoring and DSM generation. The Principal Investigator is Ralph Dubayah, at the University of Maryland. The Deputy Principal Investigator & Instrument Scientist is J. Bryan Blair at NASA's Goddard Space Flight Center. == Overview == GEDI was competitively selected as a NASA Earth Ventures Instrument (EVI) mission in 2014. Cost-capped at $94 M, GEDI is led by the University of Maryland in collaboration with NASA Goddard Space Flight Center. Climate change is closely tied to that of the carbon cycle. GEDI produces high resolution laser ranging observations of the 3D structure of the forests of Earth, which will provide answers to how deforestation has contributed to atmospheric CO2 concentrations, how much carbon


id: global-ozone-monitoring-by-occultation-of-stars-20260505-0
file: data/en.wikipedia.org/wiki/Global_Ozone_Monitoring_by_Occultation_of_Stars-0.md
category: reference
title: Global Ozone Monitoring by Occultation of Stars
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Global_Ozone_Monitoring_by_Occultation_of_Stars
date_saved: 2026-05-05T09:44:51.994880+00:00
instance: kb-cron
parent: global-ozone-monitoring-by-occultation-of-stars-20260505-0
summary:
Global Ozone Monitoring by Occultation of Stars (GOMOS), is an instrument on board the European satellite Envisat launched 1 March 2002. It is the first space instrument dedicated to the study of the atmosphere of the Earth by the technique of stellar occultation. The spectrum of stars in the ultraviolet, visible and the near infrared parts of the electromagnetic spectrum is observed. It is aimed to use GOMOS to build a climatology of ozone and related species in the middle atmosphere (15 to 100 km). == Instrument details == The 250-680 nm spectral domain is used for the determination of O3, NO2, NO3−, aerosols and temperature. In addition, two high spectral resolution channels centred at 760 and 940 nm allow measurements of O2 and H2O and two fast photometers are used to correct star scintillation perturbations and to determine high vertical resolution temperature profiles. Global latitude coverage is obtained with up to 40 stellar occultations per orbit from South Pole to North Pole. Data acquired on dark limb (night-time) are of better quality than on bright limb (day-time) because of a smaller perturbation by background light. == History == GOMOS was first proposed in 1988 as an Announcement of Opportunity


id: global-scale-observations-of-the-limb-and-disk-20260505-0
file: data/en.wikipedia.org/wiki/Global-scale_Observations_of_the_Limb_and_Disk-0.md
category: reference
title: Global-scale Observations of the Limb and Disk
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Global-scale_Observations_of_the_Limb_and_Disk
date_saved: 2026-05-05T09:44:53.195103+00:00
instance: kb-cron
parent: global-scale-observations-of-the-limb-and-disk-20260505-0
summary:
Global-scale Observations of the Limb and Disk (GOLD) is a heliophysics Mission of Opportunity (MOU) for NASA's Explorers program. Led by Richard Eastes at the Laboratory for Atmospheric and Space Physics, which is located at the University of Colorado Boulder, GOLD's mission is to image the boundary between Earth and space in order to answer questions about the effects of solar and atmospheric variability of Earth's space weather. GOLD was one of 11 proposals selected, of the 42 submitted, for further study in September 2011. On 12 April 2013, NASA announced that GOLD, along with the Ionospheric Connection Explorer (ICON), had been selected for flight in 2017. GOLD, along with its commercial host satellite SES-14, launched on 25 January 2018. == Mission concept and history == GOLD is intended to perform a two-year mission imaging Earth's thermosphere and ionosphere from geostationary orbit. GOLD is a two-channel far-ultraviolet (FUV) imaging spectrograph built by the Laboratory for Atmospheric and Space Physics at the University of Colorado Boulder and flown as a hosted payload on the commercial communications satellite SES-14. Additional organizations participating in the GOLD mission include the National Center for Atmospheric Research, Virginia Tech, the University of California, Berkeley, the University


id: gravity-science-juno-20260505-0
file: data/en.wikipedia.org/wiki/Gravity_science_(Juno)-0.md
category: reference
title: Gravity science (Juno)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Gravity_science_(Juno)
date_saved: 2026-05-05T09:44:54.396191+00:00
instance: kb-cron
parent: gravity-science-juno-20260505-0
summary:
The Gravity Science experiment and instrument set aboard the Juno Jupiter orbiter is designed to monitor Jupiter's gravity. It maps Jupiter's gravitational field, which will allow the interior of Jupiter to be better understood. It uses special hardware on Juno, and also on Earth, including the high-gain K-band and X-band communication systems of the Deep Space Network as well as Juno's Ka-band Translator System (KaTS). These components work together to detect minute changes in radio frequency (Doppler shift) to measure the spacecraft's velocity over time. The KaTS box was funded by the Italian Space Agency and overseen by professor Luciano Iess from University La Sapienza in Rome. KaTS detects signals coming from the DSN on Earth, and then sends replies in a very precise way that allows the velocity of Juno to be determined to within 0.001 millimeters per second. The spacecraft receives a tone signal on the X or Ka band and then replies using the Ka-band radio. As the spacecraft traverses the space near Jupiter, the planet, and even variations in the planets interior, cause a variation in Juno velocity. The gravity science experiment measures these velocity changes using a combination of hardware on Earth and the spacecraft,


id: habitability-brine-irradiation-and-temperature-20260505-0
file: data/en.wikipedia.org/wiki/Habitability,_Brine_Irradiation_and_Temperature-0.md
category: reference
title: Habitability, Brine Irradiation and Temperature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Habitability,_Brine_Irradiation_and_Temperature
date_saved: 2026-05-05T09:44:55.573215+00:00
instance: kb-cron
parent: habitability-brine-irradiation-and-temperature-20260505-0
summary:
Habitability, Brine Irradiation and Temperature (HABIT) is an instrument designed to harvest water from the Mars atmosphere, an experiment that might pave the way to future water farms on Mars. As part of ESA's ExoMars-2 mission, the instrument was planned to be placed on board the Kazachok lander. The launch of ExoMars-2 has been postponed to 2028. == Instrument description == HABIT is composed of two major components: BOTTLE (Brine Observation Transition to Liquid Experiment) and ENVPACK (Environmental Package). BOTTLE contains six containers protected by HEPA filters, filled with salts that will collect atmospheric water through deliquescence. Sensors in each container will measure hydration and a state in which brine formed. Salts in the instrument can be dehydrated to allow indefinite operations of the instrument. ENVPACK will contain instruments measuring ultraviolet irradiance, ground temperature, and a temperature of the atmosphere in three different directions. Most of the ENVPACK instruments were already used in Rover Environmental Monitoring Station of the NASA's Curiosity rover. The Principal Investigator of HABIT is Javier Martin-Torres. == Scientific objectives == The objectives of HABIT are: to investigate (and quantify) the habitability of the landing site in terms of availability of water, ultraviolet radiation, and temperature ranges


id: hazcam-20260505-0
file: data/en.wikipedia.org/wiki/Hazcam-0.md
category: reference
title: Hazcam
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hazcam
date_saved: 2026-05-05T09:44:56.826839+00:00
instance: kb-cron
parent: hazcam-20260505-0
summary:
Hazcams (short for hazard avoidance cameras) are photographic cameras mounted on the front and rear of NASA's Spirit, Opportunity, Curiosity and Perseverance rover missions to Mars and on the lower front portion of the Chinese Yutu rover mission to the Moon and the Zhurong rover to Mars. == Overview == The Curiosity rover's hazcams are sensitive to visible light and return black and white images of resolution 1024 × 1024 pixels. These images are used by the rovers' internal computer to autonomously navigate around hazards. Due to their positioning on both sides of the rovers, simultaneous images taken by either both front or both rear cameras can be used to produce a 3D map of the immediate surroundings. As the cameras are fixed (i.e. can not move independently of the rover), they have a wide field of view (approximately 120° both horizontally and vertically) to allow a large amount of terrain to be visible. They are considered engineering cameras since they were not designed to be used for scientific experiments. The other set of engineering cameras on the rovers are the navcams. The safe landing of the Mars Science Laboratory was initially confirmed using the vehicle's hazcams. The Perseverance cameras


id: heat-flow-and-physical-properties-package-20260505-0
file: data/en.wikipedia.org/wiki/Heat_Flow_and_Physical_Properties_Package-0.md
category: reference
title: Heat Flow and Physical Properties Package
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heat_Flow_and_Physical_Properties_Package
date_saved: 2026-05-05T09:44:58.005408+00:00
instance: kb-cron
parent: heat-flow-and-physical-properties-package-20260505-0
summary:
The Heat Flow and Physical Properties Package (HP3) is a science payload on board the InSight lander that features instruments to study the heat flow and other thermal properties of Mars. One of the instruments, a burrowing probe nicknamed "the mole", was designed to penetrate 5 m (16 ft) below Mars' surface. In March 2019, the mole burrowed a few centimeters, but then became unable to make progress due to various factors. In the following year further attempts were made to resolve the issues, with little net progress. On January 14, 2021, it was announced that efforts to drill into the martian surface using the device had been terminated. HP3 was provided by the German Aerospace Center (DLR). The hammering mechanism inside the mole was designed by the Polish company Astronika and the Space Research Centre of the Polish Academy of Sciences under contract and in cooperation with DLR. The Principal Investigator is Tilman Spohn from the German Aerospace Center. == Overview == The mission goal was to understand the origin and diversity of terrestrial planets. Information from the HP3 heat flow package was expected to reveal whether Mars and Earth formed from the same material, and determine how active


id: heat-flow-and-physical-properties-package-20260505-1
file: data/en.wikipedia.org/wiki/Heat_Flow_and_Physical_Properties_Package-1.md
category: reference
title: Heat Flow and Physical Properties Package
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heat_Flow_and_Physical_Properties_Package
date_saved: 2026-05-05T09:44:58.005408+00:00
instance: kb-cron
parent: heat-flow-and-physical-properties-package-20260505-0
summary:
=== Penetration efforts === In March 2019, the HP3 began burrowing into the surface sand, but became stalled after several centimeters by what was initially suspected to be a large rock. Further analysis and testing with a replica model on Earth suggested the problem may be due to insufficient friction. In June 2019, more evidence for this was revealed when the support structure was lifted off of the HP3 mole. The Martian regolith appeared to be compressed, leaving a gap around the probe. A technique was implemented using the lander's robotic arm to press on the soil near the probe to increase soil friction. Ultimately, this method was not able to generate enough downward force, since the HP3 probe was at the limit of the arm's range. Instead, the team used the robotic scoop to pin the probe against the edge of its hole. This method appeared successful initially, as the probe continued to dig for two weeks, until it was flush with the surface. At this time, the exposed top of the probe was too small for the scoop to press against, so the scoop was re-positioned to press down on the soil near the probe. Unfortunately, this caused


id: helios-dust-instrumentation-20260505-0
file: data/en.wikipedia.org/wiki/Helios_Dust_Instrumentation-0.md
category: reference
title: Helios Dust Instrumentation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Helios_Dust_Instrumentation
date_saved: 2026-05-05T09:44:59.180833+00:00
instance: kb-cron
parent: helios-dust-instrumentation-20260505-0
summary:
The Helios 1 and 2 spacecraft each carried two dust instruments to characterize the Zodiacal dust cloud inside the Earth’s orbit down to spacecraft positions 0.3 AU from the sun. The Zodiacal light instrument measured the brightness of light scattered by interplanetary dust along the line of sight. The in situ Micrometeoroid analyzer recorded impacts of meteoroids onto the sensitive detector surface and characterized their composition. The instruments delivered radial profiles of their measured data. Comet or meteoroid streams, and even interstellar dust were identified in the data. == Overview == The two Helios spacecraft were the result of a joint venture of West Germany's space agency DLR and NASA. The spacecraft were built in Germany and launched from Cape Canaveral Air Force Station, Florida. Helios 1 was launched in December 1974 onto an elliptic orbit between 1 and 0.31 au. Helios 2 followed in January 1976 and reached 0.29 au perihelion distance. The orbital periods were about 6 months. The Helios spacecraft were spinning with the spin axis perpendicular to the ecliptic plane. The Helios 1 spin axis pointed to ecliptic north whereas the Helios 2 orientation was inverted and the spin axis pointed to ecliptic south. The despun


id: helios-dust-instrumentation-20260505-1
file: data/en.wikipedia.org/wiki/Helios_Dust_Instrumentation-1.md
category: reference
title: Helios Dust Instrumentation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Helios_Dust_Instrumentation
date_saved: 2026-05-05T09:44:59.180833+00:00
instance: kb-cron
parent: helios-dust-instrumentation-20260505-0
summary:
The South sensor was shielded by the spacecraft rim from direct sun light, whereas the ecliptic sensor was directly exposed to the intense solar radiation (up to 13 kW/m2). Therefore, the interior of the sensor was protected by a 0.3 μm thick aluminized parylene film which was attached to the first entrance grid. In order to study the effect of micrometeoroids penetrating the film, extensive dust accelerator studies with various materials were performed. It was shown that the penetration limit of the Helios film depends strongly on the density of meteoroids. Impact experiments with a lab version of the Helios micrometeoroid sensor were performed using several materials at the accelerators at the Max Planck Institute for Nuclear Physics in Heidelberg and at the Ames Research Center, ARC, in Moffet Field. The projectile materials included iron (Fe), quartz, glass, aluminium (Al), aluminium oxide (Al2O3), polystyrene, and kaolin. The mass resolution of the mass spectra of the Helios sensors was low R = M Δ M ∼ 10 {\displaystyle R={\cfrac {M}{\Delta M}}\sim 10} , i.e. only ions of atomic mass 10 Da could be separated from ions of mass 11 Da. These mass spectra served as reference for the spectra obtained in


id: high-resolution-stereo-camera-20260505-0
file: data/en.wikipedia.org/wiki/High_Resolution_Stereo_Camera-0.md
category: reference
title: High Resolution Stereo Camera
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/High_Resolution_Stereo_Camera
date_saved: 2026-05-05T09:45:00.340228+00:00
instance: kb-cron
parent: high-resolution-stereo-camera-20260505-0
summary:
High Resolution Stereo Camera (HRSC) is a camera experiment on Mars Express. A version for Earth called HRSC-AX was also developed, as was a version for Mars 96. It has four main parts: camera head, super resolution channel, instrument frame, and digital unit. At an altitude of 250 km from Mars, SRC can produce images with a resolution of 2.3 meters/pixel of 2.35 km square Mars terrain. It has 9 channels and can produce digital terrain models. A typical image from HRSC of Mars has a resolution ranging from 12.5 for nadir (directly down) to 25 m/pixel for the furthest off-nadir shots, which can be up to 18.9 degrees. By 2012, about 61.5% of the surface of Mars was mapped at a resolution of at least 20 meters per pixel by the Mars Express mission using this camera. Another area of study is repeat imaging, to allow the study of dynamic processes on Mars. Another trick is to make short videos of the Mars surface by taking advantage of the pushbroom nature of the detector. Each section is slightly offset for a different color, but when combined, every view is used to make a short animation. By the start of


id: hiros-20260505-0
file: data/en.wikipedia.org/wiki/HiROS-0.md
category: reference
title: HiROS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/HiROS
date_saved: 2026-05-05T09:45:01.545763+00:00
instance: kb-cron
parent: hiros-20260505-0
summary:
HiROS (High Resolution Optical System) is a satellite system operating in the visible and near infra-red (NIR) optical range with a 0.5 m ground resolution. It is developed by the German Aerospace Center and will allegedly be used for espionage purposes, according to leaked diplomatic cables. The satellite has a mass of 820 kg, and can be launched from various Soyuz, Vega, or Rockot rockets. It has a revisit time of 24 h. The project was cancelled in 2012. == Instrument performance == The instrument itself has a mass of 190 kg. Its detector has a panchromatic channel between 450 and 900 nm (visible and near IR) with a ground resolution of 0.5 m. In a multichannel operation, it can achieve 2 m ground resolution. It has a signal to noise ratio of 200 and a dynamic range of 1:5000 and uses a 14 bit analog to digital converter. == References == == External links == (in English) www.ifp.uni-stuttgart.de Presentations from 2009


id: inertial-stellar-compass-20260505-0
file: data/en.wikipedia.org/wiki/Inertial_Stellar_Compass-0.md
category: reference
title: Inertial Stellar Compass
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Inertial_Stellar_Compass
date_saved: 2026-05-05T09:45:02.734752+00:00
instance: kb-cron
parent: inertial-stellar-compass-20260505-0
summary:
Inertial Stellar Compass (ISC) was a proposed instrument for an advanced navigation system designed to allow spacecraft to operate more autonomously by enabling precise attitude determination with an accuracy of better than 0.1 degrees across all three axes. It also provides the capability to recover orientation after a power loss. The ISC is small in size and consumes low power to operate. The ISC was developed by NASA as part of New Millennium program's Space Technology 6 project in collaboration with Charles Stark Draper Laboratory. The instrument functions with a combination of a miniaturized star tracker and gyroscopes. It uses a wide field-of-view active pixel star camera and a micro electromechanical system to determine the real-time stellar attitude (orientation) of the spacecraft. It has a mass of 2.5 kg (5.5 lb) and requires 3.5 W power. In 2007, it was successfully deployed and fully operational in space aboard the TacSat-2 spacecraft. As the New Millennium Program had its budget cancelled in 2009, it is unclear whether development of this instrument is ongoing. == References ==


id: infrared-interferometer-spectrometer-and-radiometer-20260505-0
file: data/en.wikipedia.org/wiki/Infrared_interferometer_spectrometer_and_radiometer-0.md
category: reference
title: Infrared interferometer spectrometer and radiometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Infrared_interferometer_spectrometer_and_radiometer
date_saved: 2026-05-05T09:45:03.977246+00:00
instance: kb-cron
parent: infrared-interferometer-spectrometer-and-radiometer-20260505-0
summary:
An infrared interferometer spectrometer and radiometer (IRIS) is a scientific instrument of the Voyager space probes which enables the measurement of three distinct properties. The instrument itself consists of two separate instruments that together share a single large-aperture telescope system. The Infrared interferometer spectrometer holds two functions as it can act as a thermometer and/or spectrometer. The thermometer allows for the observance and measurement of heat energy emitting from an object, and the spectrometer enables the identification of various elements, molecules, and compounds which may be present in an atmosphere and/or on the surface of a body. The separate radiometer allows for the measurement of reflected infrared, visible, and ultraviolet light off of a body. == History == Early versions of the IRIS were flown on the 1960s Nimbus 3 and Nimbus 4. In 1971, an early prototype was used on Mariner 9 to examine Mars. == Objectives == The instrument was included, primarily, to meet the following objectives. Determination of atmospheric vertical thermal structure (which in turn aids modeling of atmospheric dynamics). Measurement of the abundances of hydrogen and helium (as a check on theories regarding their ratio in the primitive solar nebula). Determination of the balance of energy


id: infrared-spectrometer-for-exomars-20260505-0
file: data/en.wikipedia.org/wiki/Infrared_Spectrometer_for_ExoMars-0.md
category: reference
title: Infrared Spectrometer for ExoMars
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Infrared_Spectrometer_for_ExoMars
date_saved: 2026-05-05T09:45:05.255251+00:00
instance: kb-cron
parent: infrared-spectrometer-for-exomars-20260505-0
summary:
Infrared Spectrometer for ExoMars (ISEM) was an infrared spectrometer for remote sensing designed to be part of the science payload on board the European Space Agency's Rosalind Franklin rover, tasked to search for biosignatures and biomarkers on Mars. ISEM would provide context assessment of the surface mineralogy in the vicinity of the Rosalind Franklin rover for selection of potential astrobiological targets. The Principal Investigator was Oleg Korablev from the Russian Space Research Institute (IKI). The instrument's use on the rover was cancelled, together with other Russian contributions to the project, after Russian invasion of Ukraine in 2022 and it was replaced by the Welsh-built ENFYS. == Overview == The Infrared Spectrometer for ExoMars (ISEM) was being developed by the Russian Space Research Institute (IKI). It would be the first instance of near-infrared spectroscopy (NIR) observations done from the Mars surface. The instrument would be installed on the Rosalind Franklin rover's mast to measure reflected solar radiation in the near infrared range for context assessment of the surface mineralogy in the vicinity of Rosalind Franklin for selection of potential astrobiological targets. As the number of samples obtained with the drill will be limited, the selection of high-value sites for drilling will


id: integrated-science-investigation-of-the-sun-20260505-0
file: data/en.wikipedia.org/wiki/Integrated_Science_Investigation_of_the_Sun-0.md
category: reference
title: Integrated Science Investigation of the Sun
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Integrated_Science_Investigation_of_the_Sun
date_saved: 2026-05-05T09:45:06.434344+00:00
instance: kb-cron
parent: integrated-science-investigation-of-the-sun-20260505-0
summary:
Integrated Science Investigation of the Sun or IS☉IS, is an instrument aboard the Parker Solar Probe, a space probe designed to study the Sun. IS☉IS is focused on measuring energetic particles from the Sun, including electrons, protons, and ions. The parent spacecraft was launched in early August 2018, and with multiple flybys of Venus will study the heliosphere of the Sun from less than 4 million kilometers or less than 9 solar radii. IS☉IS consists of two detectors, EPI-Lo and EPI-Hi, corresponding to detection of relatively lower and higher energy particles. EPI-Lo is designed to detect from about 20 keV per nucleon up to 15 MeV (mega electronvolts) total energy, and for electrons from about 25 keV up to 1000 keV. EPI-Hi is designed to measure charged particles from about 1– to 200 MeV per nucleon and electrons from about 0.5 to 6 MeV, according to a paper about the device. The shortname includes a symbol for the Sun, a circle with a dot in it: ☉. NASA suggests pronouncing the name as in English. == Operations == By September 2018, IS☉IS had been turned on and first light data was returned. == EPI-Hi == EPI-Hi includes: High Energy Telescope


id: interior-characterization-of-europa-using-magnetometry-20260505-0
file: data/en.wikipedia.org/wiki/Interior_Characterization_of_Europa_using_Magnetometry-0.md
category: reference
title: Interior Characterization of Europa using Magnetometry
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Interior_Characterization_of_Europa_using_Magnetometry
date_saved: 2026-05-05T09:45:07.678711+00:00
instance: kb-cron
parent: interior-characterization-of-europa-using-magnetometry-20260505-0
summary:
The Interior Characterization of Europa using Magnetometry (ICEMAG) is a multi-frequency magnetometer that was proposed to be flown on board the Europa Clipper mission to Jupiter's moon Europa, but its inclusion was cancelled in March 2019. Magnetic induction is a powerful tool for probing the subsurface and determine Europa's ocean depth, salinity, and ice shell thickness, as well as detecting erupting plume activity. The Principal Investigator is Carol Raymond, at NASA's Jet Propulsion Laboratory. On March 5, 2019, NASA's Associate Administrator for the Science Mission Directorate, Thomas Zurbuchen, announced that ICEMAG would no longer be part of the Europa Clipper mission, primarily citing recurring cost increases (over three times the original cost put forward in the proposal). A less complex magnetometer will be included on the mission. == Overview == Magnetic induction is a powerful tool for probing the subsurface. ICEMAG would have observed the magnetic field near Europa with greatly enhanced sensitivity compared to a similar instrument carried by NASA's Galileo spacecraft, which orbited Jupiter from 1995 to 2003. The magnetic field induced in Europa over many frequencies would reveal the ocean depth and ice shell thickness, especially when combined with the REASON ice penetrating radar data and the


id: international-lunar-observatory-20260505-0
file: data/en.wikipedia.org/wiki/International_Lunar_Observatory-0.md
category: reference
title: International Lunar Observatory
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/International_Lunar_Observatory
date_saved: 2026-05-05T09:45:08.826982+00:00
instance: kb-cron
parent: international-lunar-observatory-20260505-0
summary:
The International Lunar Observatory (ILO) is a private scientific and commercial lunar mission by the International Lunar Observatory Association (ILOA Hawai'i) of Kamuela, Hawaii to place a permanent observatory near the South Pole of the Moon to conduct astrophysical studies using an optical telescope and possibly an antenna dish. The mission aims to prove a conceptual design for a lunar observatory that would be reliable, low cost, and fast to implement. A precursor mission, ILO-X consisting of two small imagers (totaling less than 0.6 kg), launched on 15 February 2024 aboard the Intuitive Machines IM-1 mission to the Moon south pole region. It is hoped to be a technology precursor to a future observatories on the Moon, and other commercial initiatives. The ILO-1 mission is being organized by the International Lunar Observatory Association and the Space Age Publishing Company. It was planned to be launched in 2008 with development by SpaceDev, and was first delayed to 2013. The prime contractors originally were Moon Express, providing the MX-1E lander, and Canadensys Aerospace, providing the optical telescope system. The estimated cost in 2004 was of US$50 million. == Overview == The ILO-1 mission, was later scheduled to be launched in July 2020


id: jedi-20260505-0
file: data/en.wikipedia.org/wiki/JEDI-0.md
category: reference
title: JEDI
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/JEDI
date_saved: 2026-05-05T09:45:10.021020+00:00
instance: kb-cron
parent: jedi-20260505-0
summary:
JEDI (Jupiter Energetic-particle Detector Instrument) is an instrument on the Juno spacecraft orbiting planet Jupiter. JEDI coordinates with the several other space physics instruments on the Juno spacecraft to characterize and understand the space environment of Jupiter's polar regions, and specifically to understand the generation of Jupiter's powerful aurora. It is part of a suite of instruments to study the magnetosphere of Jupiter. JEDI consists of three identical detectors that use microchannel plates and foil layers to detect the energy, angle, and types of ion within a certain range. It can detect electrons between 40 and 500 keV (Kilo electron-volts), and hydrogen and oxygen from a few tens of keV to less than 1000 keV (1 MeV). JEDI uses radiation-hardened Application Specific Integrated Circuits (ASIC)s. JEDI was turned on in January 2016 while still en route to Jupiter, to study interplanetary space. JEDI uses solid state detectors (SSDs) to measure the total energy (E) of both the ions and the electrons. The MCP anodes and the SSD arrays are configured to determine the directions of arrivals of the incoming charged particles. The instruments also use fast triple coincidence and optimum shielding to suppress penetrating background radiation and incoming UV foreground.


id: jovian-auroral-distributions-experiment-20260505-0
file: data/en.wikipedia.org/wiki/Jovian_Auroral_Distributions_Experiment-0.md
category: reference
title: Jovian Auroral Distributions Experiment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Jovian_Auroral_Distributions_Experiment
date_saved: 2026-05-05T09:45:11.241000+00:00
instance: kb-cron
parent: jovian-auroral-distributions-experiment-20260505-0
summary:
Jovian Auroral Distributions Experiment (JADE) is an instrument that detects and measures ions and electrons around the spacecraft. It is a suite of detectors on the Juno Jupiter orbiter (launched 2011, orbiting Jupiter since 2016). JADE includes JADE-E, JADE-I, and the EBox. JADE-E and JADE-I are sensors that are spread out on the spacecraft, and the EBox is located inside the Juno Radiation Vault. EBox stands for Electronics Box. JADE-E is for detecting electrons from 0.1 to 100 keV, and there are three JADE-E sensors on Juno. JADE-I is for detecting ions from 5 eV to 50 keV. It is designed to return data in situ on Jupiter's auroral region and magnetospheric plasmas, by observing electrons and ions in this region. It is primarily focused on Jupiter, but it was turned on in January 2016 while still en route to study inter-planetary space (when it was still several million miles from Jupiter at that time). JADE was built by Southwest Research Institute (SwRI), located in the United States in Texas. Two other instruments help understand the magnetosphere of Jupiter, WAVES and MAG. The JEDI instrument measures higher energy ions and electrons and JADE lower energy ones; therefore they are complementary.


id: jovian-infrared-auroral-mapper-20260505-0
file: data/en.wikipedia.org/wiki/Jovian_Infrared_Auroral_Mapper-0.md
category: reference
title: Jovian Infrared Auroral Mapper
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Jovian_Infrared_Auroral_Mapper
date_saved: 2026-05-05T09:45:12.422936+00:00
instance: kb-cron
parent: jovian-infrared-auroral-mapper-20260505-0
summary:
Jovian Infrared Auroral Mapper (JIRAM) is an instrument on the Juno spacecraft in orbit of the planet Jupiter. It is an image spectrometer and was contributed by Italy. Similar instruments are on ESA Rosetta, Venus Express, and Cassini-Huygens missions. The primary goal of JIRAM is to probe the upper layers of Jupiter's atmosphere down to pressures of 5–7 bars (72–102 pound/square inch) at infrared wavelengths in the 2–5 μm interval using an imager and a spectrometer. The Jupiter's atmosphere and auroral regions are targeted for study. In particular it has been designed to study the dynamics and chemistry in the atmosphere, perhaps determining the how Jovian hot spots form. H+3 ions, ammonia, and phosphine can be mapped. The ion of Hydrogen H+3 is rare on Earth, but is one of the most common ions in the universe and known as protonated molecular hydrogen or the trihydrogen cation. Despite the intense magnetosphere of Jupiter, the JIRAM is expected to be operational for at least the first eight orbits. Previously Jupiter was observed by an Infrared imaging spectrometer called NIMS (Near-Infrared Mapping Spectrometer) on the Galileo Jupiter orbiter. JIRAM was used to observe Earth during its flyby en route to Jupiter. These


id: kepler-photometer-20260505-0
file: data/en.wikipedia.org/wiki/Kepler_photometer-0.md
category: reference
title: Kepler photometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Kepler_photometer
date_saved: 2026-05-05T09:45:13.590989+00:00
instance: kb-cron
parent: kepler-photometer-20260505-0
summary:
The Kepler photometer is the main instrument on NASA's Kepler space telescope. It is a Schmidt telescope (95 cm clear aperture, 140 cm mirror) with an array of 42 2200x1024 CCDs in the focal plane; each CCD is flat, but they are mounted on a curved structure to account for the curved focal plane. The CCDs are not abutting, so the focal plane is not entirely covered, but since the mission's goal is to observe a sample of stars, this doesn't matter. == References == Kepler Mission: Photometer and Spacecraft [1]


id: lara-20260505-0
file: data/en.wikipedia.org/wiki/LaRa-0.md
category: reference
title: LaRa
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/LaRa
date_saved: 2026-05-05T09:45:14.880276+00:00
instance: kb-cron
parent: lara-20260505-0
summary:
LaRa (Lander Radioscience) was a Belgian radio science experiment that will be placed onboard Kazachok, planned to be launched in 2022. LaRa will monitor the Doppler frequency shift of a radio signal traveling between the Martian lander and the Earth. These Doppler measurements will be used to precisely observe the orientation and rotation of Mars, leading to a better knowledge of the internal structure of the planet. Kazachok was cancelled, and the ExoMars mission was moved to 2028. == Instrument description == LaRa will obtain coherent two-way Doppler measurements from the X band radio link between Kazachok and large antennas on Earth, like those of the Deep space network. The relative radial velocity between the Earth and the Martian lander is inferred from Doppler shifts measured at the Earth ground stations. Masers at the Earth's ground stations ensure the frequency stability. Véronique Dehant, scientist at the Royal Observatory of Belgium, is the Principal Investigator of the experiment. Antwerp Space N.V., a subsidiary of OHB SE, is the manufacturer of the LaRa instrument. The main parts of the transponder are the coherent detector, the transmitter with the solid-state power amplifier, the micro controller unit, the receiver and the power supply unit.


id: long-lived-in-situ-solar-system-explorer-20260505-0
file: data/en.wikipedia.org/wiki/Long_Lived_In-situ_Solar_System_Explorer-0.md
category: reference
title: Long Lived In-situ Solar System Explorer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Long_Lived_In-situ_Solar_System_Explorer
date_saved: 2026-05-05T09:45:16.047216+00:00
instance: kb-cron
parent: long-lived-in-situ-solar-system-explorer-20260505-0
summary:
Long Lived In-situ Solar System Explorer (LLISSE) is a possible NASA payload on the Russian Venera-D mission to Venus. == Overview == LLISSE uses new materials and heat-resistant electronics that would enable independent operation for about 90 Earth days. This endurance may allow it to obtain periodic measurements of weather data to update global circulation models and quantify near surface atmospheric chemistry variability. Its anticipated instruments include wind speed/direction sensors, temperature sensors, pressure sensors, and a chemical multi-sensor array. LLISSE is a small 20 cm (7.9 in) cube of about 10 kg (22 lb). The Venera-D lander may carry two LLISSE units; one would be battery-powered (3,000 h), and the other would be wind-powered. == References ==


id: lyra-20260505-0
file: data/en.wikipedia.org/wiki/LYRA-0.md
category: reference
title: LYRA
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/LYRA
date_saved: 2026-05-05T09:45:17.282783+00:00
instance: kb-cron
parent: lyra-20260505-0
summary:
LYRA (Lyman Alpha Radiometer) is the solar UV radiometer on board Proba-2, a European Space Agency technology demonstration satellite that was launched on November 2, 2009. LYRA has been designed and manufactured by a Belgian-Swiss-German consortium (ROB-SIDC, PMOD/WRC, IMOMEC, CSL, MPS and BISA) with additional international collaborations (Japan, USA, Russia, and France). Jean-François Hochedez (ROB) is Principal Investigator, Yves Stockman (CSL) is Project Manager, and Werner Schmutz (PMOD) is Lead co-Investigator. LYRA will monitor the Solar irradiance in four UV passbands. They have been chosen for their relevance to solar physics, aeronomy and Space Weather: the 115-125 nm Lyman-α channel, the 200-220 nm Herzberg continuum channel, the Aluminium filter channel (17-50 nm) including He II at 30.4 nm, and the Zirconium filter channel (1-20 nm). The Radiometric calibration of the instrument is traceable to Synchrotron source standards, Physikalisch-Technische Bundesanstalt (PTB) and National Institute of Standards and Technology (NIST). Its stability will be monitored by onboard calibration light sources (light-emitting diodes), which allow distinguishing between potential degradations of the detectors and filters. Additionally, a redundancy strategy contributes to the accuracy and the stability of the measurements. LYRA will benefit from wide bandgap detectors based on diamond: it will be the first


id: magnetometer-juno-20260505-0
file: data/en.wikipedia.org/wiki/Magnetometer_(Juno)-0.md
category: reference
title: Magnetometer (Juno)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Magnetometer_(Juno)
date_saved: 2026-05-05T09:45:18.504639+00:00
instance: kb-cron
parent: magnetometer-juno-20260505-0
summary:
Magnetometer (MAG) is an instrument suite on the Juno orbiter for planet Jupiter. The MAG instrument includes both the Fluxgate Magnetometer (FGM) and Advanced Stellar Compass (ASC) instruments. There two sets of MAG instrument suites, and they are both positioned on the far end of three solar panel array booms. Each MAG instrument suite observes the same swath of Jupiter, and by having two sets of instruments, determining what signal is from the planet and what is from spacecraft is supported. Avoiding signals from the spacecraft is another reason MAG is placed at the end of the solar panel boom, about 10 m (33 feet) and 12 m (39 feet) away from the central body of the Juno spacecraft. The MAG instrument is designed to detect the magnetic field of Jupiter, which is one of the largest structures in the Solar System. If one could see Jupiter's magnetic field from Earth, it would appear five times larger than the full moon in the sky despite being nearly 1700 times farther away. Jupiter's internal magnetic field prevents the solar wind, a stream of ionized particles emitted by the Sun, from interacting directly with its atmosphere, and instead diverts it away from


id: mars-organic-molecule-analyser-20260505-0
file: data/en.wikipedia.org/wiki/Mars_Organic_Molecule_Analyser-0.md
category: reference
title: Mars Organic Molecule Analyser
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mars_Organic_Molecule_Analyser
date_saved: 2026-05-05T09:45:20.894507+00:00
instance: kb-cron
parent: mars-organic-molecule-analyser-20260505-0
summary:
The Mars Organic Molecule Analyser (MOMA) is a mass spectrometer-based instrument on board the Rosalind Franklin rover to be launched in 2028 to Mars on an astrobiology mission. It will search for organic compounds (carbon-containing molecules) in the collected soil samples. By characterizing the molecular structures of detected organics, MOMA can provide insights into potential molecular biosignatures. MOMA will be able to detect organic molecules at concentrations as low as 10 parts-per-billion by weight (ppbw). MOMA examines solid crushed samples exclusively; it does not perform atmospheric analyses. The Principal Investigator is Fred Goesmann, from the Max Planck Institute for Solar System Research in Germany. == Overview == The goal of MOMA is to seek signs of past life on Mars (biosignatures) by analysing a wide range of organic compounds that may be found in drilled samples acquired from 2 meters below the Martian surface by the Rosalind Franklin rover. MOMA examines solid crushed samples only; it does not perform atmospheric analyses. MOMA will first volatilize solid organic compounds so that they can be analysed by a mass spectrometer; this volatilisation of organic material is achieved by two different techniques: laser desorption and thermal volatilisation, followed by separation using four GC-MS


id: mars-radiation-environment-experiment-20260505-0
file: data/en.wikipedia.org/wiki/Mars_Radiation_Environment_Experiment-0.md
category: reference
title: Mars Radiation Environment Experiment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mars_Radiation_Environment_Experiment
date_saved: 2026-05-05T09:45:22.065459+00:00
instance: kb-cron
parent: mars-radiation-environment-experiment-20260505-0
summary:
The Mars Radiation Environment Experiment (MARIE) was designed to measure the radiation environment of Mars using an energetic particle spectrometer as part of the science mission of the 2001 Mars Odyssey spacecraft (launched on April 7, 2001). It was led by NASA's Johnson Space Center and the science investigation was designed to characterize aspects of the radiation environment both on the way to Mars and while it was in the Martian orbit. Since space radiation presents an extreme hazard to crews of interplanetary missions the experiment was an attempt to predict anticipated radiation doses that would be experienced by future astronauts and it helped determine possible effects of Martian radiation on human beings. Space radiation comes from cosmic rays emitted by Earth's local star, the Sun, and from stars beyond the Solar System as well. Space radiation can trigger cancer and cause damage to the central nervous system. Similar instruments are flown on the Space Shuttles and on the International Space Station (ISS), but none have ever flown outside Earth's protective magnetosphere, which blocks much of this radiation from reaching the surface of our planet. MARIE was turned off on 28 October 2003 after communication was lost during a large


id: marsis-20260505-0
file: data/en.wikipedia.org/wiki/MARSIS-0.md
category: reference
title: MARSIS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MARSIS
date_saved: 2026-05-05T09:45:23.265306+00:00
instance: kb-cron
parent: marsis-20260505-0
summary:
MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) is a low frequency, pulse-limited radar sounder and altimeter developed by the University of Rome La Sapienza and Alenia Spazio (today Thales Alenia Space Italy). The Italian MARSIS instrument, which is operated by the European Space Agency, is operational and orbits Mars as an instrument for the ESA's Mars Express exploration mission. The MARSIS Principal Investigator is Giovanni Picardi from the University of Rome "La Sapienza", Italy. It features ground-penetrating radar capabilities, which uses synthetic aperture technique and a secondary receiving antenna to isolate subsurface reflections. MARSIS identified buried basins on Mars. MARSIS was funded by ASI (Italy) and NASA (USA). The processor runs the real-time operating system EONIC Virtuoso. == Deployment == On May 4, 2005, Mars Express deployed the first of its two 20-metre-long radar booms for the MARSIS experiment. At first the boom didn't lock fully into place; however, exposing it to sunlight for a few minutes on May 10 fixed the glitch. The second 20 m boom was successfully deployed on June 14. Both 20 m booms were needed to create a 40 m dipole antenna for MARSIS to work; a less crucial 7-meter-long monopole antenna was


id: mass-spectrometer-for-planetary-exploration-20260505-0
file: data/en.wikipedia.org/wiki/Mass_Spectrometer_for_Planetary_Exploration-0.md
category: reference
title: Mass Spectrometer for Planetary Exploration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mass_Spectrometer_for_Planetary_Exploration
date_saved: 2026-05-05T09:45:24.462092+00:00
instance: kb-cron
parent: mass-spectrometer-for-planetary-exploration-20260505-0
summary:
The MAss Spectrometer for Planetary EXploration (MASPEX) is a time-of-flight mass spectrometer capable of high-resolution and high-sensitivity that allows the determination of a wide variety of chemical compounds in complex mixtures. This instrument will fly on board the planned Europa Clipper orbiter to explore Jupiter's moon Europa. This astrobiology mission will analyse the composition of Europa's surface while in orbit, and will directly assess its internal ocean habitability by flying through Europa's tenuous atmosphere. On 27 May 2016 it was announced that MASPEX was selected to fly on the mission. The instrument has also been proposed to fly on three Discovery program missions: Enceladus Life Finder (ELF), comet Hartley 2 (PRIME), and to the main belt comet Read (Proteus). It also has applications for probes, landers, and sample return missions. The original Principal Investigator was Jack Waite, and the Technical Lead is Tim Brockwell, from the Southwest Research Institute. In 2020 NASA announced that Jim Burch of Southwest Research Institute would become the Principal Investigator and that some instrument capabilities might be reduced due to technical and financial limitations. == Overview == MASPEX is a next generation spectrometer with significantly improved performance over existing instruments, that was developed over 10


id: materials-adherence-experiment-20260505-0
file: data/en.wikipedia.org/wiki/Materials_Adherence_Experiment-0.md
category: reference
title: Materials Adherence Experiment
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Materials_Adherence_Experiment
date_saved: 2026-05-05T09:45:25.685217+00:00
instance: kb-cron
parent: materials-adherence-experiment-20260505-0
summary:
The Materials Adherence Experiment (MAE) was a material science experiment conducted between July 4, 1997, and August 12, 1997, during NASA's Mars Pathfinder mission. This was a joint experiment between NASA and the Jet Propulsion Laboratory at the California Institute of Technology that consisted of a small module mounted to Pathfinder's rover Sojourner that examined the effects of Martian surface dust on solar cells. == Purpose == Using solar power on the Martian surface is challenging because the Martian atmosphere has a significant amount of dust suspended in it. In addition to blocking sunlight from reaching Mars's surface, dust particles gradually settle out of the air and onto objects. As Pathfinder was NASA's first Mars surface mission to be solar-powered, the effect of Martian dust settling on solar cells was not well understood before the mission. It was predicted at the time that dust particles in the Martian atmosphere would settle on the solar cells powering Pathfinder, blocking sunlight from striking them and slowly causing Pathfinder to lose power. Since knowing how the settling of dust out of Mars's atmosphere would affect solar cell performance would be critical to subsequent solar-powered missions on Mars, the MAE was included aboard the


id: microwave-humidity-sounder-20260505-0
file: data/en.wikipedia.org/wiki/Microwave_humidity_sounder-0.md
category: reference
title: Microwave humidity sounder
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Microwave_humidity_sounder
date_saved: 2026-05-05T09:45:26.866232+00:00
instance: kb-cron
parent: microwave-humidity-sounder-20260505-0
summary:
The Microwave Humidity Sounder (MHS) is a five-channel passive microwave radiometer, with channels from 89 to 190 GHz. It is very similar in design to the AMSU-B instrument, but some channel frequencies have been altered. It is used to study profiles of atmospheric water vapor and provide improved input data to the cloud-clearing algorithms in the IR and MW sounder suites. Instruments were launched on NOAA's POES satellite series starting with NOAA-18 launched in May 2005 and the European Space Agency's MetOp series starting with MetOp-A launched in October 2006, continuing with MetOp-B launched in September 2012 and Metop-C launched in November 2018. The follow on instrument to MHS is MWS on the Metop-SGA satellites. The Microwave Humidity Sounder was designed and developed by Astrium EU in Portsmouth, UK, under contract to EUMETSAT. == Instrument characteristics == Heritage: AMSU-B, HSB Swath: 1650 km Spatial resolution: 17 km horizontal at nadir Mass: 63 kg Duty cycle: 100% Power: 74 W (BOL) Data rate: 4.2 kbit/s Field of View: ± 49.5 degrees cross-track Instrument Instantaneous Field of View: 1.1 degrees circular Table 1: Radiometric characteristics of the MHS == References == == External links == NOAA KLM User's Guide


id: microwave-radiometer-juno-20260505-0
file: data/en.wikipedia.org/wiki/Microwave_Radiometer_(Juno)-0.md
category: reference
title: Microwave Radiometer (Juno)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Microwave_Radiometer_(Juno)
date_saved: 2026-05-05T09:45:28.069249+00:00
instance: kb-cron
parent: microwave-radiometer-juno-20260505-0
summary:
Microwave Radiometer (MWR) is an instrument on the Juno orbiter sent to planet Jupiter. MWR is a multi-wavelength microwave radiometer for making observations of Jupiter's deep atmosphere. MWR can observe radiation from 1.37 to 50 cm in wavelength, from 600 MHz to 22 GHz in frequencies. This supports its goal of observing the previously unseen atmospheric features and chemical abundances hundreds of miles or kilometers into Jupiter's atmosphere. MWR is designed to detect six different frequencies in that range using separate antennas. MWR views Jupiter's microwave radiation so it can see up to hundreds of miles deep into the planet. In August 2016, as Juno swung closely by the planet MWR achieved a penetration of 200 to 250 miles (350 to 400 kilometers) below the surface cloud layer. MWR is designed to make observations below the cloud-tops, especially detecting the abundances of certain chemicals and determining dynamic features. These depths have not been observed before. MWR was launched aboard the Juno spacecraft on August 5, 2011 (UTC) from Cape Canaveral, USA, as part of the New Frontiers program, and after an interplanetary journey that including a swingby of Earth, entered a polar orbit of Jupiter on July 5, 2016 (UTC),


id: microwave-sounding-unit-20260505-0
file: data/en.wikipedia.org/wiki/Microwave_sounding_unit-0.md
category: reference
title: Microwave sounding unit
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Microwave_sounding_unit
date_saved: 2026-05-05T09:45:29.211966+00:00
instance: kb-cron
parent: microwave-sounding-unit-20260505-0
summary:
The microwave sounding unit (MSU) was the predecessor to the Advanced Microwave Sounding Unit (AMSU). The MSU was first launched aboard the TIROS-N satellite in late 1978 and provided global coverage (from Pole to Pole). It carries a 4-channel microwave radiometer, operating between 50 and 60 GHz. Spatial resolution on the ground was 2.5 deg in longitude and latitude (about 250 km circle). There were 9 different MSUs launched; the most recent one on NOAA-14. They provided measurements of the temperature of the troposphere and lower stratosphere until 1998, when the first AMSU was deployed. AMSU provides many more channels and finer resolution (about 50 km). Table 1 lists some characteristics of the MSU. The radiometer's antenna scans underneath the satellite through nadir, and its polarization vector rotates with the scan angle. In the table, "vertical polarization near nadir" means that the E-vector is parallel to the scan direction at nadir, and "horizontal polarization" means the orthogonal direction. Table 1 Radiometric characteristics of the Microwave Sounding Unit == Applications == The MSU was used by NOAA for meteorological analyses in combination with two infrared instruments, and sometimes alone, for post-analysis of weather events and other atmospheric phenomena such as waves.


id: mimos-ii-20260505-0
file: data/en.wikipedia.org/wiki/MIMOS_II-0.md
category: reference
title: MIMOS II
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MIMOS_II
date_saved: 2026-05-05T09:45:30.407890+00:00
instance: kb-cron
parent: mimos-ii-20260505-0
summary:
MIMOS II is the miniaturised Mössbauer spectrometer, developed by Dr. Göstar Klingelhöfer at the Johannes Gutenberg University in Mainz, Germany, that is used on the Mars Exploration Rovers Spirit and Opportunity for close-up investigations on the Martian surface of the mineralogy of iron-bearing rocks and soils. MIMOS II uses a Cobalt-57 gamma ray source of about 300 mCi at launch which gave a 6-12 hr time for acquisition of a standard MB spectrum during the primary mission on Mars, depending on total Fe content and which Fe-bearing phases are present. Cobalt-57 has a half-life of only 271.8 days (h The MIMOS II sensorheads used snMars are approx 9 cm x 5 cm x 4 cm and weigh about 400g. The MIMOS II system also includes a circuit board of about 100g. == References ==


id: mini-tes-20260505-0
file: data/en.wikipedia.org/wiki/Mini-TES-0.md
category: reference
title: Mini-TES
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mini-TES
date_saved: 2026-05-05T09:45:31.559953+00:00
instance: kb-cron
parent: mini-tes-20260505-0
summary:
The Miniature Thermal Emission Spectrometer (Mini-TES) is an infrared spectrometer used for detecting the composition of a material (typically rocks) from a distance. By making its measurements in the thermal infrared part of the electromagnetic spectrum, it has the ability to penetrate through the dust coatings common to the Martian surface which is usually problematic for remote sensing observations. There is one on each of the two Mars Exploration Rovers. == Development == The Mini-TES was originally developed by Raytheon for the Department of Geological Sciences at Arizona State University. The Mini-TES is a miniaturized version of Raytheon's Mars Global Surveyor (MGS) TES, built by Arizona State University and Raytheon SAS’ Santa Barbara Remote Sensing. The MGS TES data helped scientists choose landing sites for the Spirit and Opportunity Mars explorer rovers. == Martian soil == The Mini-TES is used for identifying promising rocks and soils for closer examination, and to determine the processes that formed Martian rocks. It measures the infrared radiation that the target rock or object emits in 167 different wavelengths, providing information about the target's composition. One particular goal is to search for minerals that were formed by the action of water, such as carbonates and


id: modular-optoelectronic-multispectral-scanner-20260505-0
file: data/en.wikipedia.org/wiki/Modular_optoelectronic_multispectral_scanner-0.md
category: reference
title: Modular optoelectronic multispectral scanner
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Modular_optoelectronic_multispectral_scanner
date_saved: 2026-05-05T09:45:32.762948+00:00
instance: kb-cron
parent: modular-optoelectronic-multispectral-scanner-20260505-0
summary:
The modular optoelectronic multispectral scanner (MOMS) is a scanning system for spaceborne, geoscientific remote sensing applications used in satellite navigation systems for sensing atmospheric and oceanic systems. The scanner is combination of separate spectrometer blocks. == History == The modular optoelectronic multispectral scanner is an optical technology programme funded by the German Ministry for Research and Technology. It was jointly designed and developed by DLR, LMU and EADS Astrium. == Characteristics == The modular structure of MOMS makes it suitable for use in wide variety of geo-spatial missions, the modules being sensor, optical lens, electronics and filters. The first flight of MOMS yielded high-resolution images with 20x20 m ground pixel size from about 300 km orbital altitude. === MOMS-01 === MOMS01 consists of five instruments mounted on a carbon-fiber structure: The optical module with four objectives, eight arrays, and associated shutters. Each module represents one spectral band, consisted of filters, dual-lens optics, four CCD detector line-scanning arrays, and preamplifier electronics. A power box for overall power control. A logic box for all sensor function control (including real-time correction, and formatting of the source data stream from the optical module) A HDDT (high-density digital tape) recorder. A pressurized container for the


id: moonlight-20260505-0
file: data/en.wikipedia.org/wiki/MoonLIGHT-0.md
category: reference
title: MoonLIGHT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MoonLIGHT
date_saved: 2026-05-05T09:45:33.985632+00:00
instance: kb-cron
parent: moonlight-20260505-0
summary:
MoonLIGHT (Moon Laser Instrumentation for General relativity High accuracy Tests) is a laser retroreflector developed as a collaboration primarily between the University of Maryland in the United States, and the Italian National Institute for Nuclear Physics - National Laboratories of Frascati (INFN-LNF) to complement and expand on the Lunar Laser Ranging experiment started with the Apollo Program in 1969. MoonLIGHT was planned to be launched in July 2020 as a secondary payload on the MX-1E lunar lander built by the private company Moon Express. However, the launch of the MX-1E has been cancelled. In 2018 INFN proposed to the European Space Agency (ESA) the MoonLIGHT Pointing Actuators (MPAc) project and was contracted by ESA to deliver it. MPAc is an INFN development for ESA, with auxiliary support by the Italian Space Agency (ASI) for prototyping work. In 2021, ESA agreed with NASA to launch MPAc with a Commercial Lunar Payload Services (CLPS) mission. Nova-C, the lander on which MPAc will be integrated, is designed by Intuitive Machines and the landing site is Reiner Gamma. The expected launch date of the Nova-C mission carrying the instrument, IM-3, is in 2026. == Overview == Laser Ranging is a technique used to perform


id: mssta-20260505-0
file: data/en.wikipedia.org/wiki/MSSTA-0.md
category: reference
title: MSSTA
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/MSSTA
date_saved: 2026-05-05T09:45:35.207408+00:00
instance: kb-cron
parent: mssta-20260505-0
summary:
The Multi-Spectral Solar Telescope Array (MSSTA) was a sounding rocket payload built by Arthur B. C. Walker Jr. at Stanford University in the 1990s to test EUV/XUV imaging of the Sun using normal incidence EUV-reflective multilayer optics. == History == MSSTA contained a large number of individual telescopes (> 10), all trained on the Sun and all sensitive to slightly different wavelengths of ultraviolet light. Like all sounding rockets, MSSTA flew for approximately 14 minutes per mission, about 5 minutes of which were in space—just enough time to test a new technology or yield "first results" science. MSSTA is one of the last solar observing instruments to use photographic film rather than a digital camera system such as a CCD. MSSTA used film instead of a CCD in order to achieve the highest possible spatial resolution and to avoid the electronics difficulty presented by the large number of detectors that would have been required for its many telescopes. MSSTA and its sister rocket, NIXT, were prototypes for normal incidence extreme ultraviolet imaging telescopes that are in use today, as well as the historic EIT instrument aboard the SOHO spacecraft, and the TRACE spacecraft. MSSTA flew three times: once in 1991


id: multi-angle-imaging-spectroradiometer-20260505-0
file: data/en.wikipedia.org/wiki/Multi-angle_imaging_spectroradiometer-0.md
category: reference
title: Multi-angle imaging spectroradiometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Multi-angle_imaging_spectroradiometer
date_saved: 2026-05-05T09:45:36.352254+00:00
instance: kb-cron
parent: multi-angle-imaging-spectroradiometer-20260505-0
summary:
The multi-angle imaging spectroradiometer (MISR) is a scientific instrument on the Terra satellite launched by NASA on 18 December 1999. This device is designed to measure the intensity of solar radiation reflected by the Earth system (planetary surface and atmosphere) in various directions and spectral bands; it became operational in February 2000. Data generated by this sensor have been proven useful in a variety of applications including atmospheric sciences, climatology and monitoring terrestrial processes. The MISR instrument consists of an innovative configuration of nine separate digital cameras that gather data in four different spectral bands of the solar spectrum. One camera points toward the nadir, while the others provide forward and aftward view angles at 26.1°, 45.6°, 60.0°, and 70.5°. As the instrument flies overhead, each region of the Earth's surface is successively imaged by all nine cameras in each of four wavelengths (blue, green, red, and near-infrared). The data gathered by MISR are useful in climatological studies concerning the disposition of the solar radiation flux in the Earth's system. MISR is specifically designed to monitor the monthly, seasonal, and long-term trends of atmospheric aerosol particle concentrations including those formed by natural sources and by human activities, upper air winds


id: nadir-and-occultation-for-mars-discovery-20260505-0
file: data/en.wikipedia.org/wiki/Nadir_and_Occultation_for_Mars_Discovery-0.md
category: reference
title: Nadir and Occultation for Mars Discovery
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nadir_and_Occultation_for_Mars_Discovery
date_saved: 2026-05-05T09:45:37.538199+00:00
instance: kb-cron
parent: nadir-and-occultation-for-mars-discovery-20260505-0
summary:
Nadir and Occultation for MArs Discovery (NOMAD) is a 3-channel spectrometer on board the ExoMars Trace Gas Orbiter (TGO) launched to Mars orbit on 14 March 2016. NOMAD is designed to perform high-sensitivity orbital identification of atmospheric components, concentration and temperature, their sources, loss, and cycles. It measures the sunlight reflected from the surface and atmosphere of Mars, and it analyses its wavelength spectrum to identify the components of the Martian atmosphere that may suggest a biological source. The Principal Investigator is Ann Carine Vandaele, from the Belgian Institute for Space Aeronomy, Belgium. == Overview == NOMAD is one of four science instruments on board the European ExoMars TGO orbiter. This spectrometer consists of three separate channels: solar occultation (SO), limb nadir and occultation (LNO), and ultraviolet and visible spectrometer (UVIS). The first two channels work in the infrared (2.2 to 4.3 μm); the third channel (UVIS) works in the UV-visible range (0.2 to 0.65 μm), which is able to measure ozone, sulphuric acid, and perform aerosol studies. Measurements are carried out during solar occultation, i.e. the instrument points toward the sunset as the orbiter moves toward or away the dark side of Mars. It also measures in nadir mode,


id: navcam-20260505-0
file: data/en.wikipedia.org/wiki/Navcam-0.md
category: reference
title: Navcam
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Navcam
date_saved: 2026-05-05T09:45:38.703648+00:00
instance: kb-cron
parent: navcam-20260505-0
summary:
Navcam, short for navigational camera, is a type of camera found on certain robotic rovers or spacecraft used for navigation without interfering with scientific instruments. Navcams typically take wide angle photographs that are used to plan the next moves of the vehicle or object tracking. == Overview == The Mars Curiosity rover has two pairs of black and white navigation cameras mounted on the mast to support ground navigation. The cameras have a 45 degree angle of view and use visible light to capture stereoscopic 3-D imagery. These cameras, like those on the Mars Pathfinder missions support use of the ICER image compression format. European Space Agency Rosetta spacecraft used a single camera with 5 degree field of view and 12 bit 1024x1024px resolution allowing for visual tracking on each of spacecraft approaches to the asteroids and finally the comet. == Gallery == == See also == Astrionics Hazard avoidance camera (Hazcam) Panoramic camera (Pancam) Optical, Spectroscopic, and Infrared camera OSIRIS List of NASA cameras on spacecraft Mars rover == References ==


id: odin-osiris-20260505-0
file: data/en.wikipedia.org/wiki/Odin-OSIRIS-0.md
category: reference
title: Odin-OSIRIS
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Odin-OSIRIS
date_saved: 2026-05-05T09:45:41.000273+00:00
instance: kb-cron
parent: odin-osiris-20260505-0
summary:
OSIRIS (Optical Spectrograph and InfraRed Imager System) is an instrument that measures vertical profiles of spectrally dispersed, limb scattered sunlight from the upper troposphere into the lower mesosphere. OSIRIS is one of two instruments on the Odin satellite, launched February, 2001 (the other instrument being a sub-mm radiometer) into a Sun-synchronous, 6 pm/6 am local time orbit at 600 km. This restricts OSIRIS sunlit observations to the Northern hemisphere in May, June, July and August, and the Southern hemisphere in November, December, January and February. Global coverage from 82°S to 82°N occurs on the months adjoining the equinoxes. OSIRIS measurements began November, 2001 and continue to the present. == Objectives == Stratospheric ozone science: To elucidate the geographical extent of, and mechanisms responsible for, ozone depletion in the "ozone hole" region and to study dilution effects and possible heterogeneous chemistry even outside of the polar regions due to sulphate aerosols. Coupling of atmospheric regions: To study some of the mechanisms that provide coupling between the upper and lower atmosphere, e.g., downward transport of NO with its effects on ozone photochemistry and the vertical exchange of minor species such as odd oxygen, CO, and H2O. == Instrument == The OSIRIS spectrograph


id: optical-payload-for-lasercomm-science-20260505-0
file: data/en.wikipedia.org/wiki/Optical_Payload_for_Lasercomm_Science-0.md
category: reference
title: Optical Payload for Lasercomm Science
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Optical_Payload_for_Lasercomm_Science
date_saved: 2026-05-05T09:45:42.173012+00:00
instance: kb-cron
parent: optical-payload-for-lasercomm-science-20260505-0
summary:
Optical PAyload for Lasercomm Science (OPALS) is a spacecraft communication instrument developed at the Jet Propulsion Laboratory that was tested on the International Space Station (ISS) from 18 April 2014 to 17 July 2014 to demonstrate the technology for laser communications systems between spacecraft and ground stations. The purpose of OPALS is to do research into replacing traditional radio-frequency (RF) communications which are currently used on spacecraft. This will allow spacecraft to increase the rate at which data is downlinked by 10 to 100 times. It also will have less error than RF communication. It launched from Cape Canaveral to the ISS on 18 April 2014 on a Falcon 9 SpaceX CRS-3 Dragon capsule resupply. The experiment used commercial products rather than space qualified components. == Science objectives == The goal of the OPALS mission was to demonstrate a downlink of a short video from space using laser communication. In doing so, the following was studied: Maintenance of an optical link between the ground and space with various environmental and operational conditions Processing of distorted data Procedure design for setting up the optical link What equipment is used for sending and receiving signal == Mission architecture == Communications and commands


id: orbiting-carbon-observatory-3-20260505-0
file: data/en.wikipedia.org/wiki/Orbiting_Carbon_Observatory_3-0.md
category: reference
title: Orbiting Carbon Observatory 3
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Orbiting_Carbon_Observatory_3
date_saved: 2026-05-05T09:45:43.336222+00:00
instance: kb-cron
parent: orbiting-carbon-observatory-3-20260505-0
summary:
The Orbiting Carbon Observatory-3 (OCO-3) is a NASA-JPL instrument designed to measure carbon dioxide in Earth's atmosphere. The instrument is mounted on the Japanese Experiment Module-Exposed Facility on board the International Space Station (ISS). OCO-3 was launched as part of CRS-17 on 4 May 2019 at 06:48 UTC. The nominal mission lifetime is ten years. OCO-3 was assembled using spare materials from the Orbiting Carbon Observatory-2 satellite. Because the OCO-3 instrument is similar to the OCO-2 instrument, it is expected to have similar performance with its measurements used to quantify CO2 to 1 ppm precision or better at 3 Hz. == History and timeline == 24 February 2009 - Orbiting Carbon Observatory was launched on a Taurus XL rocket but failed to achieve orbit when the fairing failed to separate from the satellite. 1 February 2010 - The 2010 President's budget included funding for development and re-flight of an OCO replacement. October 2010 - The Orbiting Carbon Observatory-2 project went into implementation phase. 2 July 2014 - OCO-2 was successfully launched from Vandenberg Air Force Base with a Delta II rocket. 2015 - Funding for the OCO-3 project cancelled. 22 December 2015 - OCO-3 project authorized to proceed. Funding was


id: planetary-fourier-spectrometer-20260505-0
file: data/en.wikipedia.org/wiki/Planetary_Fourier_Spectrometer-0.md
category: reference
title: Planetary Fourier Spectrometer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Planetary_Fourier_Spectrometer
date_saved: 2026-05-05T09:45:44.525581+00:00
instance: kb-cron
parent: planetary-fourier-spectrometer-20260505-0
summary:
The Planetary Fourier Spectrometer (PFS) is an infrared spectrometer built by the Istituto Nazionale di Astrofisica (Italian National Institute for Astrophysics) along with the Istituto di Fisica dello spazio Interplanetario and the Consiglio Nazionale delle Ricerche (Italian National Research Council). The instrument is currently used by the European Space Agency on both the Mars Express Mission and the Venus Express Mission. It consists of four units which together weigh around 31.4 kg, including a pointing device, a power supply, a control unit, and an interferometer with electronics. The main objective of the instrument is to provide temperature profiles of Mars's carbon dioxide atmosphere, and to the study composition of the planet's atmosphere through the infrared radiation that is reflected and emitted by the planet. == Methane in the Martian atmosphere == In March 2004, Professor Vittorio Formisano, the researcher in charge of the Mars Express Planetary Fourier Spectrometer, announced the discovery of methane in the Martian atmosphere. However, methane cannot persist in the Martian atmosphere for more than a few hundred years since it can be broken down by sunlight. Thus, this discovery suggests that the methane is being continually replenished by some unidentified volcanic or geologic process, or that


id: plasma-instrument-for-magnetic-sounding-20260505-0
file: data/en.wikipedia.org/wiki/Plasma_Instrument_for_Magnetic_Sounding-0.md
category: reference
title: Plasma Instrument for Magnetic Sounding
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_Instrument_for_Magnetic_Sounding
date_saved: 2026-05-05T09:45:45.712227+00:00
instance: kb-cron
parent: plasma-instrument-for-magnetic-sounding-20260505-0
summary:
The Plasma Instrument for Magnetic Sounding (PIMS) is a Faraday cup based instrument that will fly on board the Europa Clipper orbiter to explore Jupiter's moon Europa. PIMS will measure the plasma that populates Jupiter's magnetosphere and Europa's ionosphere. The principal investigator is Dr. Adrienn Luspay-Kuti, from the Johns Hopkins University Applied Physics Laboratory (APL). == Overview == The plasma in Jupiter's magnetosphere interacts with Europa's atmosphere. This interaction results in magnetic field perturbations. While understanding this plasma interaction is inherently interesting, it is also crucial for successful magnetic sounding Europa's subsurface ocean. The interaction of the Jovian magnetic field with Europa's subsurface ocean produces a magnetic induction signature that is used to determine the ice shell thickness, ocean depth, and ocean salinity of Europa's subsurface ocean. Separating the sources of magnetic field perturbations produces a better understanding of the ocean's properties. The Plasma Instrument for Magnetic Sounding (PIMS) is a Faraday cup-based instrument that will measure the plasma of Jupiter's magnetosphere and Europa's ionosphere. Such devices on spacecraft date back to Explorer 10 in 1961 and were used by the Voyager 1 spacecraft to study Jupiter's magnetosphere in 1979. == Science goals == The three science goals of PIMS


id: plasma-wave-instrument-20260505-0
file: data/en.wikipedia.org/wiki/Plasma_wave_instrument-0.md
category: reference
title: Plasma wave instrument
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Plasma_wave_instrument
date_saved: 2026-05-05T09:45:46.896589+00:00
instance: kb-cron
parent: plasma-wave-instrument-20260505-0
summary:
A plasma wave instrument (PWI), also known as a plasma wave receiver, is a device capable of detecting vibrations in outer space plasma and transforming them into audible sound waves or air vibrations that can be heard by the human ear. This instrument was pioneered by then-University of Iowa physics professor, Donald Gurnett. Plasma wave instruments are commonly employed on space probes such as GEOTAIL, Polar, Voyager I and II (see Plasma Wave Subsystem), and Cassini–Huygens. == Operating principle == Vibrations in the audible frequency range are perceived by humans when air vibrates against their eardrum. Air, or some other vibrating medium such as water, is essential for sound perception by the human ear. Without a medium to transmit it, the sound produced by a source will not be heard by a human. There is no air in outer space, nor is there any other type of medium capable of transmitting vibrations from a source to a human ear. However, there are sources in outer space that vibrate at frequencies audible to humans if only there were some transmitting medium to carry those vibrations from the source to a human eardrum. One such source capable of vibrating at audible frequencies


