diff --git a/_index.db b/_index.db index 3b4b4009d..7c86799dc 100644 Binary files a/_index.db and b/_index.db differ diff --git a/data/en.wikipedia.org/wiki/Autocollimator-0.md b/data/en.wikipedia.org/wiki/Autocollimator-0.md new file mode 100644 index 000000000..3d771db05 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Autocollimator-0.md @@ -0,0 +1,81 @@ +--- +title: "Autocollimator" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Autocollimator" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:43.937135+00:00" +instance: "kb-cron" +--- + +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 speed, accuracy and cost-effectiveness, making it one of the most practical procedures available. Widely used in workshops, tool rooms, inspection departments and quality control laboratories, these highly sensitive instruments are designed to measure extremely small angular displacements, squareness, twist and parallelism. + + +== Laser analyzing autocollimator == +Current technology allows has improved the autocollimation instrument to allow for direct measurements of incoming laser beams. This capability opens allows for inter-alignment between optics, mirrors and lasers. +This fusion between the century-old technology of autocollimation with recent laser technology results has resulted in a versatile instrument capable of measuring the inter-alignment between multiple line of sights with respect to: mechanical datum, alignment of laser cavity, measurement of multiple rollers parallelism in roll to roll machinery, laser divergence angle and its spatial stability. + + +== Total station autocollimator == +The concept of autocollimation as an optical instrument was conceived about a century ago for non-contact measurements of angles, as done in total stations. Hybrid technology fulfills a need recently developed by novel photonics applications has created for the alignment and measurement of optics and lasers. Implementing motorized focusing offers an additional measurement dimension by focusing on the area to be examined and performing alignment and deviations from alignment on the scale of microns. This is relevant in the adjustment phase as well as final testing and examination phases of integrated systems. Recent progress has been made in with the aim to serve the photonics AR/VR industry, involving development in interalingment, fusion of several wavelengths including NIR into one system, and measurements of multi laser array such as VCSEL in respect with other optical sensors, to improve angular accurate optical measurements to a resolution of 0.01 arcseconds. + + +== Integrated autocollimator-based optical metrology == +Recent developments in optical metrology have extended the role of the autocollimator beyond single-axis angular measurement into multi-functional, integrated measurement systems. By combining digital imaging sensors, multi-wavelength illumination, and computational analysis, modern autocollimator-based instruments can perform several optical diagnostics traditionally requiring multiple standalone laboratory devices. +Such systems use the autocollimator’s inherent sensitivity to angular deviations as a shared reference framework for additional measurements, including laser beam profiling, wavefront characterization, multi-axis alignment, and geometric verification. By operating within a common optical axis and coordinate system, these instruments reduce cumulative alignment errors that arise when measurements are distributed across separate devices. +Integrated autocollimator-based systems are increasingly designed for in-situ and in-line use, enabling real-time alignment and verification during optical assembly or laser manufacturing processes. This approach contrasts with conventional optical laboratories, where measurements are typically performed offline and sequentially. +The concept has been implemented in various hybrid optical metrology platforms developed by manufacturers and as well described in academic and patent literature addressing automated alignment and smart manufacturing. +The front runner of this technology is the so called Total Station Autocollimator implementing into one instrument up to 10 different instruments to be chosen by a press of a button. +As optical systems increase in complexity, integrated autocollimator-based metrology is increasingly viewed as a practical method for consolidating multiple optical measurements into a single, traceable instrument. + + +== Typical applications == +An electronic autocollimator can be used in the measurement of straightness of machine components (such as guide ways) or the straightness of lines of motion of machine components. Flatness measurement of granite surface plates, for example, can be performed by measuring straightness of multiple lines along the flat surface, then summing the deviations in line angle over the surface. Recent advancements in applications allow angular orientation measurement of wafers. This could also be done without obstructing lines of sight to the wafer's surface itself. It is applicable in wafer measuring machines and wafer processing machines. Other applications include: + +Aircraft assembly jigs +Satellite testing +Steam and gas turbines +Marine propulsion machinery +Printing presses +Air compressors +Cranes +Diesel engines +Nuclear reactors +Coal conveyors +Shipbuilding and repair +Rolling mills +Rod and wire mills +Extruder barrels +Optical measurement applications: + +Retroreflector measurement +Roof prism measurement +Optical assembly procedures +Alignment of beam delivery systems +Alignment of laser cavity +Testing perpendicularity of laser rods in respect to its axis +Real time measurement of angular stability of mirror elements. + + +== See also == +Autocollimation +Collimator + + +== References == +Lowell, Tom. "Small Angles and Autocollimators". Vermont Photonics. Archived from the original on 28 June 2022. Retrieved 7 May 2006. +Morel, Jerrat. "Principles of Operation". Micro-Radian Instruments. Archived from the original on 7 May 2007. Retrieved 14 May 2007. +Aharon, Oren. "Metrology system for inter-alignment of lasers, telescopes, and mechanical datum". Duma Optronics. Retrieved 12 October 2015. +Aharon, Oren. "Telescopic Analyzing System Tests Laser Collimation and Propagation". Duma Optronics. Archived from the original on 5 June 2017. Retrieved 5 June 2017. +Aharon, Oren. "Laser Autocollimator and Bore Sighting". Duma Optronics. Archived from the original on 24 July 2014. Retrieved 21 July 2014. +O. Aharon and I. Vishnia (2021). "The Hybrid Autocollimator". Photonicsviews. 18. Photonics Views: 60–63. doi:10.1002/phvs.202100001. S2CID 234030641. +O. Aharon (2022). "Total Station Autocollimator for Photonics Professionals". Novus Light. Retrieved 28 February 2022. +Möller, T. (2018). "Integrated optical metrology for alignment and inspection in photonics manufacturing". Proceedings of SPIE. 10678. SPIE. doi:10.1117/12.2300123. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Cast_Glance-0.md b/data/en.wikipedia.org/wiki/Cast_Glance-0.md new file mode 100644 index 000000000..23edd4a41 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Cast_Glance-0.md @@ -0,0 +1,20 @@ +--- +title: "Cast Glance" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Cast_Glance" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:45.118201+00:00" +instance: "kb-cron" +--- + +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) \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Cathetometer-0.md b/data/en.wikipedia.org/wiki/Cathetometer-0.md new file mode 100644 index 000000000..86a74395f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Cathetometer-0.md @@ -0,0 +1,20 @@ +--- +title: "Cathetometer" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Cathetometer" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:46.323492+00:00" +instance: "kb-cron" +--- + +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 == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Double_violin-0.md b/data/en.wikipedia.org/wiki/Double_violin-0.md new file mode 100644 index 000000000..9378f5d53 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Double_violin-0.md @@ -0,0 +1,21 @@ +--- +title: "Double violin" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Double_violin" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:31.335988+00:00" +instance: "kb-cron" +--- + +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 double violin, the first made by Ken Parker of Stuyvesant Sound in New York and the latest edition crafted by luthier John Jordan and released in 2023. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-0.md b/data/en.wikipedia.org/wiki/Electricity_meter-0.md new file mode 100644 index 000000000..e1c9e45c3 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-0.md @@ -0,0 +1,31 @@ +--- +title: "Electricity meter" +chunk: 1/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +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 than estimated usage. + +=== Direct current === + +Many experimental types of meter were developed. Thomas Edison at first worked on a direct current (DC) electromechanical meter with a direct reading register, but instead developed an electrochemical metering system, which used an electrolytic cell to totalise current consumption. At periodic intervals the plates were removed and weighed, and the customer billed. The electrochemical meter was labor-intensive to read and not well received by customers. +DC meters often measured charge in ampere hours. Since the voltage of the supply should remain substantially constant, the reading of the meter was proportional to actual energy consumed. For example, if a meter recorded that 100 ampere hours had been consumed on a 200-volt supply, then 20 kilowatt-hours of energy had been supplied. +In 1885 Ferranti offered a mercury motor meter with a register similar to gas meters; this had the advantage that the consumer could easily read the meter and verify consumption. Another early electromagnetic meter with visible readouts was a DC meter by Hermann Aron, who patented it in 1884. Hugo Hirst of the British General Electric Company introduced it commercially into Great Britain from 1888. Aron's power meter (later adapted for AC power) recorded the total charge used over time, and showed it on a series of clock dials. + +Electrochemical meters were also improved to be directly read out, such as the Bastian electrolytic meter invented in 1897, and the Wright electrolytic meter or 'Reason' meter which was patented in 1900. The Wright meter, used mainly in the United Kingdom, consisted of a vertically mounted glass structure with a mercury reservoir at the top of the meter. As current was drawn from the supply, electrochemical action transferred the mercury to the bottom of the column. The height of the mercury indicated the total charge. The meter had to be reset to zero before the reserve of mercury ran out. Reset was performed by inverting the meter, restoring the mercury to the reservoir. + +=== Alternating current === +The first specimen of the AC kilowatt-hour meter produced on the basis of Hungarian Ottó Bláthy's patent and named after him was presented by the Ganz Works at the Frankfurt Fair in the autumn of 1889, and the first induction kilowatt-hour meter was already marketed by the factory at the end of the same year. These were the first alternating-current watt-hour meters, known by the name of Bláthy-meters. The AC kilowatt hour meters used at present operate on the same principle as Bláthy's original invention. Also around 1889, Elihu Thomson of the American General Electric company developed a recording watt meter (watt-hour meter) based on an ironless commutator motor. This meter overcame the disadvantages of the electrochemical type and could operate on either alternating or direct current. +In 1894 Oliver Shallenberger of the Westinghouse Electric Corporation applied the induction principle previously used only in AC ampere hour meters to produce a watt-hour meter of the modern electromechanical form, using an induction disk whose rotational speed was made proportional to the power in the circuit. The Bláthy meter was similar to Shallenberger and Thomson meter in that they are two-phase motor meter. Although the induction meter would only work on alternating current, it eliminated the delicate and troublesome commutator of the Thomson design. Shallenberger fell ill and was unable to refine his initial large and heavy design, although he did also develop a polyphase version. +In 1902, William Morris Mordey and Guy Carey Fricker patented the Mordey-Fricker electricity meter, which operated on a different principle from motor-type meters, using a clock mechanism whose balance wheel oscillated at a rate directly proportional to the current. It was suitable for both direct and alternating current without frequency error, and was designed for small domestic installations of twelve to thirty lamps. + +== Units == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-1.md b/data/en.wikipedia.org/wiki/Electricity_meter-1.md new file mode 100644 index 000000000..55aa7462b --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-1.md @@ -0,0 +1,52 @@ +--- +title: "Electricity meter" +chunk: 2/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +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 computer power supplies draw their current at the voltage peak to fill their internal storage elements. This can lead to a significant voltage drop near the supply voltage peak which shows as a flattening of the voltage waveform. This flattening causes odd harmonics which are not permissible if they exceed specific limits, as they are not only wasteful, but may interfere with the operation of other equipment. Harmonic emissions are mandated by law in EU and other countries to fall within specified limits. +In addition to metering based on the amount of energy used, other types of metering are available. Meters which measured the amount of charge (coulombs) used, known as ampere hour meters, were used in the early days of electrification. These were dependent upon the supply voltage remaining constant for accurate measurement of energy usage, which was not a likely circumstance with most supplies. The most common application was in relation to special-purpose meters to monitor charge / discharge status of large batteries. Some meters measured only the length of time for which charge flowed, with no measurement of the magnitude of voltage or current being made. These are only suited for constant-load applications and are rarely used today. + +== Operation == + +Electricity meters operate by continuously measuring the instantaneous voltage (volts) and current (amperes) to give energy used (in joules, kilowatt-hours etc.). Meters for smaller services (such as small residential customers) can be connected directly in-line between source and customer. For larger loads, more than about 200 ampere of load, current transformers are used, so that the meter can be located somewhere other than in line with the service conductors. The meters fall into two basic categories, electromechanical and electronic. + +=== Electromechanical === +The most common type of electricity meter is the electromechanical watt-hour meter. +On a single-phase AC supply, the electromechanical induction meter operates through electromagnetic induction by counting the revolutions of a non-magnetic, but electrically conductive, metal disc which is made to rotate at a speed proportional to the power passing through the meter. The number of revolutions is thus proportional to the energy usage. The voltage coil consumes a small and relatively constant amount of power, typically around 2 watts which is not registered on the meter. The current coil similarly consumes a small amount of power in proportion to the square of the current flowing through it, typically up to a couple of watts at full load, which is registered on the meter. +The disc is acted upon by two sets of induction coils, which form, in effect, a two phase linear induction motor. One coil is connected in such a way that it produces a magnetic flux in proportion to the voltage and the other produces a magnetic flux in proportion to the current. The field of the voltage coil is delayed by 90 degrees, due to the coil's inductive nature, and calibrated using a lag coil. This produces eddy currents in the disc and the effect is such that a force is exerted on the disc in proportion to the product of the instantaneous current and instantaneous voltage. A permanent magnet acts as an eddy current brake, exerting an opposing force proportional to the speed of rotation of the disc. The equilibrium between these two opposing forces results in the disc rotating at a speed proportional to the power or rate of energy usage. The disc drives a register mechanism which counts revolutions, much like the odometer in a car, in order to render a measurement of the total energy used. +Different phase configurations use additional voltage and current coils. + +The disc is supported by a spindle which has a worm gear which drives the register. The register is a series of dials which record the amount of energy used. The dials may be of the cyclometer type, an odometer-like display that is easy to read where for each dial a single digit is shown through a window in the face of the meter, or of the pointer type where a pointer indicates each digit. With the dial pointer type, adjacent pointers generally rotate in opposite directions due to the gearing mechanism. +The amount of energy represented by one revolution of the disc is denoted by the symbol Kh which is given in units of watt-hours per revolution. The value 7.2 is commonly seen. Using the value of Kh one can determine their power consumption at any given time by timing the disc with a stopwatch. + + + + + P + = + + + + 3600 + ⋅ + K + h + + t + + + + + {\displaystyle P={{3600\cdot Kh} \over t}} + +. +Where: \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-2.md b/data/en.wikipedia.org/wiki/Electricity_meter-2.md new file mode 100644 index 000000000..abb6e9421 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-2.md @@ -0,0 +1,32 @@ +--- +title: "Electricity meter" +chunk: 3/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +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 or LED display, and some can also transmit readings to remote places. In addition to measuring energy used, some electronic meters can also record other parameters of the load and supply such as instantaneous and maximum rate of usage demands, voltages, power factor and reactive power used etc. They can also support time-of-day billing, for example, recording the amount of energy used during on-peak and off-peak hours. +The meter has a power supply, a metering engine, a processing and communication engine (i.e. a microcontroller), and other add-on modules such as a real time clock (RTC), a liquid crystal display, infra red communication ports/modules and so on. +The metering engine is given the voltage and current inputs and has a voltage reference, samplers and quantisers followed by an analog to digital conversion section to yield the digitised equivalents of all the inputs. These inputs are then processed using a digital signal processor to calculate the various metering parameters. +The largest source of long-term errors in the meter is drift in the preamp, followed by the precision of the voltage reference. Both of these vary with temperature as well, and vary wildly when meters are outdoors. Characterising and compensating for these is a major part of meter design. +The processing and communication section has the responsibility of calculating the various derived quantities from the digital values generated by the metering engine. This also has the responsibility of communication using various protocols and interface with other addon modules connected as slaves to it. +RTC and other add-on modules are attached as slaves to the processing and communication section for various input/output functions. On a modern meter most if not all of this will be implemented inside the microprocessor, such as the RTC, LCD controller, temperature sensor, memory and analog to digital converters. + +=== Communication methods === +Remote meter reading is a practical example of telemetry. It saves the cost of a human meter reader and the resulting mistakes, but it also allows more measurements, and remote provisioning. Many smart meters now include a switch to interrupt or restore service. +Historically, rotating meters could report their metered information remotely, using a pair of electrical contacts attached to a KYZ line. +A KYZ interface is a Form C contact supplied from the meter. In a KYZ interface, the Y and Z wires are switch contacts, shorted to K for a measured amount of energy. When one contact closes the other opens to provide count accuracy security. Each contact change of state is considered one pulse. The frequency of pulses indicates the power demand. The number of pulses indicates energy metered. When incorporated into an electromechanical meter, the relay changes state with each full or half rotation of the meter disc. Each state change is called a "pulse." +KYZ outputs were historically attached to "totaliser relays" feeding a "totaliser" so that many meters could be read all at once in one place. +KYZ outputs are also the classic way of attaching electricity meters to programmable logic controllers, HVACs or other control systems. Some modern meters also supply a contact closure that warns when the meter detects a demand near a higher electricity tariff, to improve demand side management. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-3.md b/data/en.wikipedia.org/wiki/Electricity_meter-3.md new file mode 100644 index 000000000..3da19d842 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-3.md @@ -0,0 +1,36 @@ +--- +title: "Electricity meter" +chunk: 4/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +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 protocol proposed for this purpose is DLMS/COSEM which can operate over any medium, including serial ports. The data can be transmitted by Zigbee, Wi-Fi, telephone lines or over the power lines themselves. Some meters can be read over the internet. Other more modern protocols are also becoming widely used, like OSGP (Open Smart Grid Protocol). +Electronic meters now also use low-power radio, GSM, GPRS, Bluetooth, IrDA, as well as RS-485 wired link. The meters can store the entire usage profiles with timestamps and relay them at the click of a button. The demand readings stored with the profiles accurately indicate the load requirements of the customer. This load profile data is processed at the utilities for billing and planning purposes. +AMR (Automatic Meter Reading) and RMR (Remote Meter Reading) describe various systems that allow meters to be checked remotely, without the need to send a meter reader. An electronic meter can transmit its readings by telephone line or radio to a central billing office. + +== Monitoring and billing methods == + +=== Commercial uses === +Large commercial and industrial premises may use electronic meters which record power usage in blocks of half an hour or less. This is because most electricity grids have demand surges throughout the day, and the power company may wish to give price incentives to large customers to reduce demand at these times. These demand surges often correspond to meal times or, famously, to advertisements interrupting popular television programmes, such as the TV pickup. + +=== Home energy monitoring === + +A potentially powerful means to reduce household energy consumption is to provide convenient real-time feedback to users so they can change their energy using behaviour. Recently, low-cost energy feedback displays have become available, that may be able to measure energy (Watt-hours), momentary power (wattage), and may additionally be able to measure the MAINS voltage, current, uptime, apparent power, capturing peak wattage and peak current, and have a manually set clock. The display may indicate the power consumption over the week graphically. +A study using a consumer-readable meter in 500 Ontario homes by Hydro One showed an average 6.5% drop in total electricity use when compared with a similarly sized control group. Hydro One subsequently offered free power monitors to 30,000 customers based on the success of the pilot. Projects such as Google PowerMeter, take information from a smart meter and make it more readily available to users to help encourage conservation. + +Plug-in electricity meters (or plug load meters) measure energy used by individual appliances. There are a variety of models available on the market today but they all work on the same basic principle. The meter is plugged into an outlet, and the appliance to be measured is plugged into the meter. Such meters can help in energy conservation by identifying major energy users, or devices that consume excessive standby power. Web resources can also be used, if an estimate of the power consumption is enough for the research purposes. A power meter can often be borrowed from the local power authorities or a local public library. + +=== Multiple tariff === + +Electricity retailers may wish to charge customers different tariffs at different times of the day to better reflect the costs of generation and transmission. Since it is typically not cost effective to store significant amounts of electricity during a period of low demand for use during a period of high demand, costs will vary significantly depending on the time of day. Low cost generation capacity (baseload) such as nuclear can take many hours to start, meaning a surplus in times of low demand, whereas high cost but flexible generating capacity (such as gas turbines) must be kept available to respond at a moment's notice (spinning reserve) to peak demand, perhaps being used for a few minutes per day, which is very expensive. +Some multiple tariff meters use different tariffs for different amounts of demand. These are usually industrial meters. +Domestic variable-rate meters generally permit two to three tariffs ("peak", "off-peak" and "shoulder") and in such installations a simple electromechanical time switch may be used. Historically, these have often been used in conjunction with electrical storage heaters or hot water storage systems. +Multiple tariffs are made easier by time of use (TOU) meters which incorporate or are connected to a time switch and which have multiple registers. +Switching between the tariffs may happen via ripple control, or via a radio-activated switch. In principle, a sealed time switch can also be used, but is considered more vulnerable to tampering to obtain cheaper electricity. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-4.md b/data/en.wikipedia.org/wiki/Electricity_meter-4.md new file mode 100644 index 000000000..8405cb745 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-4.md @@ -0,0 +1,26 @@ +--- +title: "Electricity meter" +chunk: 5/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +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 supply to the cheaper rate during the 7 hour night time period, not just the storage heater circuit. The downside of this is that the daytime rate per kWh is significantly higher, and that standing charges are sometimes higher. For example, as of July 2017, normal ("single rate") electricity costs 17.14p per kWh in the London region on the standard default tariff for EDF Energy (the post-privatisation incumbent electricity supplier in London), with a standing charge of 18.90p per day. The equivalent Economy 7 costs are 21.34p per kWh during the peak usage period with 7.83p per kWh during the off-peak usage period, and a standing charge of 18.90p per day. Timer switches installed on washing machines, tumble dryers, dishwashers and immersion heaters may be set so that they only switch on during the off-peak usage period. + +=== Smart meters === + +Smart meters go a step further than simple AMR (automatic meter reading). They offer additional functionality including a real-time or near real-time reads, power outage notification, and power quality monitoring. They allow price setting agencies to introduce different prices for consumption based on the time of day and the season. +Another type of smart meter uses nonintrusive load monitoring to automatically determine the number and type of appliances in a residence, how much energy each uses and when. This meter is used by electric utilities to do surveys of energy use. It eliminates the need to put timers on all of the appliances in a house to determine how much energy each uses. + +=== Prepayment meters === + +The standard business model of electricity retailing involves the electricity company billing the customer for the amount of energy used in the previous month or quarter. In some countries, if the retailer believes that the customer may not pay the bill, a prepayment meter may be installed. This requires the customer to make advance payment before electricity can be used. If the available credit is exhausted then the supply of electricity is cut off by a relay. +In the UK, mechanical prepayment coin meters used to be common, both in private rented accommodation and residential customers of the electricity boards, the nationalised electricity sector. Disadvantages of these included the need for regular visits to remove the cash, and risk of theft of the cash in the meters by both customers and burglars. +The first automated pre-payment meters were introduced by London Electricity, in conjunction with the Schlumberger Metering based in Felixstowe, UK. They were initially called Key Meters and later renamed Budget Meters. They avoided the 60,000 disconnections for non-payment per annum and the many disadvantages of cash prepayment. They were also popular with customers who wanted a convenient payment method, especially in short term tenancies. Well over 1 million such meters were installed across the UK in the first few years after introduction. Modern solid-state electricity meters, in conjunction with smart cards, have removed these disadvantages and such meters are commonly used for customers considered to be a poor credit risk. In the UK, customers can use organisations such as the Post Office Limited or PayPoint network, where rechargeable tokens (Quantum cards for natural gas, or plastic "keys" for electricity) can be loaded with whatever money the customer has available. +In Indonesia, Northern Ireland, South Africa and Sudan, prepaid meters are recharged by entering a unique, encoded twenty digit number using a keypad. This makes the tokens, which may be electronically delivered or printed on a slip of paper at point of purchase, very cheap to produce. +Around the world, experiments are going on, especially in developing countries, to test pre-payment systems. In some cases, prepayment meters have not been accepted by customers. There are various groups, such as the Standard Transfer Specification (STS) association, which promote common standards for prepayment metering systems across manufacturers. Prepaid meters using the STS standard are used in many countries. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-5.md b/data/en.wikipedia.org/wiki/Electricity_meter-5.md new file mode 100644 index 000000000..595defcc2 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-5.md @@ -0,0 +1,26 @@ +--- +title: "Electricity meter" +chunk: 6/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +=== 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 purchase power by the hour using either forecast pricing or real-time pricing. +Some utilities allow residential customers to pay hourly rates, such as in Illinois, which uses day ahead pricing. + +=== Power export metering === + +Many electricity customers are installing their own electricity generating equipment, whether for reasons of economy, redundancy or environmental reasons. When a customer is generating more electricity than required for his own use, the surplus may be exported back to the power grid. Customers that generate back into the "grid" usually must have special equipment and safety devices to protect the grid components (as well as the customer's own) in case of faults (electrical short circuits) or maintenance of the grid (say voltage on a downed line coming from an exporting customers facility). +This exported energy may be accounted for in the simplest case by the meter running backwards during periods of net export, thus reducing the customer's recorded energy usage by the amount exported. This in effect results in the customer being paid for his/her exports at the full retail price of electricity. Unless equipped with a ratchet or equivalent, a standard meter will accurately record power flow in each direction by simply running backwards when power is exported. Where allowed by law, utilities maintain a profitable margin between the price of energy delivered to the consumer and the rate credited for consumer-generated energy that flows back to the grid. +Lately, upload sources typically originate from renewable sources (e.g., wind turbines, photovoltaic cells), or gas or steam turbines, which are often found in cogeneration systems. Another potential upload source that has been proposed is plug-in hybrid car batteries (vehicle-to-grid power systems). This requires a "smart grid," which includes meters that measure electricity via communication networks that require remote control and give customers timing and pricing options. Vehicle-to-grid systems could be installed at workplace parking lots and garages and at park and rides and could help drivers charge their batteries at home at night when off-peak power prices are cheaper, and receive bill crediting for selling excess electricity back to the grid during high-demand hours. + +== Location == + +The location of an electricity meter varies with each installation. Possible locations include on a utility pole serving the property, in a street-side cabinet (meter box) or inside the premises adjacent to the consumer unit / distribution board. Electricity companies may prefer external locations as the meter can be read without gaining access to the premises but external meters may be more prone to vandalism. +Current transformers permit the meter to be located remotely from the current-carrying conductors. This is common in large installations. For example, a substation serving a single large customer may have metering equipment installed in a cabinet, without bringing heavy cables into the cabinet. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-6.md b/data/en.wikipedia.org/wiki/Electricity_meter-6.md new file mode 100644 index 000000000..97075a507 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-6.md @@ -0,0 +1,22 @@ +--- +title: "Electricity meter" +chunk: 7/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +=== 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, safer voltages at the socket (usually 120 V), and provides two voltages to customers: neutral to phase (usually 120 V), and phase to phase (usually 240 V). Additionally, three-wire customers normally have neutral wired to the zero side of the generator's windings, which gives earthing that can be easily measured to be safe. These meters have a metering equation of Watts = 0.5 x volts x (amps of phase A − amps of phase B), with volts measured between the phase wires. +Industrial power is normally supplied as three phase power. There are two forms: three wire, or four wire with a system neutral. In "three wire" or "three wire delta", there is no neutral but an earth ground is the safety ground. The three phases have voltage only relative to each other. This distribution method has one fewer wire, is less expensive, and is common in Asia, Africa, and many parts of Europe. In regions that mix residences and light industry, it is common for this to be the only distribution method. A meter for this type normally measures two of the windings relative to the third winding, and adds the watts. One disadvantage of this system is that if the safety earth fails, it is difficult to discover this by direct measurement, because no phase has a voltage relative to earth. +In the four-wire three-phase system, sometimes called "four-wire wye", the safety ground is connected to a neutral wire that is physically connected to the zero-voltage side of the three windings of the generator or transformer. Since all power phases are relative to the neutral in this system, if the neutral is disconnected, it can be directly measured. In the United States, the National Electrical Code requires neutrals to be of this type. In this system, power meters measure and sum all three phases relative to the neutral. +In North America, it is common for electricity meters to plug into a standardised socket outdoors, on the side of a building. This allows the meter to be replaced without disturbing the wires to the socket, or the occupant of the building. Some sockets may have a bypass while the meter is removed for service. The amount of electricity used without being recorded during this small time is considered insignificant when compared to the inconvenience which might be caused to the customer by cutting off the electricity supply. Most electronic meters in North America use a serial protocol, ANSI C12.18. +In many other countries the supply and load terminals are in the meter housing itself. Cables are connected directly to the meter. In some areas the meter is outside, often on a utility pole. In others, it is inside the building in a niche. If inside, it may share a data connection with other meters. If it exists, the shared connection is often a small plug near the post box. The connection is often EIA-485 or infrared with a serial protocol such as IEC 62056. +In 2014, networking to meters is rapidly changing. The most common schemes seem to combine an existing national standard for data (e.g. ANSI C12.19 or IEC 62056) operating via the Internet Protocol with a small circuit board for powerline communication, or a digital radio for a mobile phone network, or an ISM band. + +== Accuracy == +Electricity meters are required to register the energy consumed within an acceptable degree of accuracy. Any significant error in the registered energy can represent a loss to the electricity supplier, or the consumer being over billed. The accuracy is generally laid down in statute for the location in which the meter is installed. Statutory provisions may also specify a procedure to be followed should the accuracy be disputed. +For the United Kingdom, any installed electricity meter is required to accurately record the consumed energy, but it is permitted to under-read by 3.5%, or over-read by 2.5%. Disputed meters are initially verified with a check meter operating alongside the disputed meter. The final resort is for the disputed meter to be fully tested both in the installed location and at a specialist calibration laboratory. Approximately 93% of disputed meters are found to be operating satisfactorily. A refund of electricity paid for, but not consumed (but not vice versa) will only be made if the laboratory is able to estimate how long the meter has been misregistering. This contrasts with gas meters where if a meter is found to be under reading, it is assumed that it has under read for as long as the consumer has had a gas supply through it. Any refund due is limited to the previous six years. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-7.md b/data/en.wikipedia.org/wiki/Electricity_meter-7.md new file mode 100644 index 000000000..430fd244d --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-7.md @@ -0,0 +1,47 @@ +--- +title: "Electricity meter" +chunk: 8/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +== 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 meters, though countermeasures are common. +Some combinations of capacitive and inductive load can interact with the coils and mass of a rotor and cause reduced or reverse motion. +All of these effects can be detected by the electric company, and many modern meters can detect or compensate for them. +The owner of the meter normally secures the meter against tampering. Revenue meters' mechanisms and connections are sealed. Meters may also measure VAR-hours (the reflected load), neutral and DC currents (elevated by most electrical tampering), ambient magnetic fields, etc. Even simple mechanical meters can have mechanical flags that are dropped by magnetic tampering or large DC currents. +Newer computerised meters usually have counter-measures against tampering. AMR (Automated Meter Reading) meters often have sensors that can report opening of the meter cover, magnetic anomalies, extra clock setting, glued buttons, inverted installation, reversed or switched phases etc. +Some tampers bypass the meter, wholly or in part. Safe tampers of this type normally increase the neutral current at the meter. Most split-phase residential meters in the United States are unable to detect neutral currents. However, modern tamper-resistant meters can detect and bill it at standard rates. +Disconnecting a meter's neutral connector is unsafe because shorts can then pass through people or equipment rather than a metallic ground to the generator or earth. +A phantom loop connection via an earth ground is often much higher resistance than the metallic neutral connector. Even if an earth ground is safe, metering at the substation can alert the operator to tampering. Substations, inter-ties, and transformers normally have a high-accuracy meter for the area served. Power companies normally investigate discrepancies between the total billed and the total generated, in order to find and fix power distribution problems. These investigations are an effective method to discover tampering. +Power thefts in the United States are often connected with indoor marijuana grow operations. Narcotics detectives associate abnormally high power usage with the lighting such operations require. Indoor marijuana growers aware of this are particularly motivated to steal electricity simply to conceal their usage of it. + +== Global standards for Electricity Metering == + +Electricity meters are governed by various standards worldwide to ensure accuracy, reliability, and interoperability. These standards vary by region and are often based on national or international regulations. Below are the key standards used in different regions. +European Standards + +In Europe, electricity meters are primarily regulated under the Measuring Instruments Directive (MID), established by the European Union. MID ensures that electricity meters meet specific technical and operational criteria for accurate billing. Key standards include: +EN 50470-1 to EN 50470-3: These standards specify general requirements, particular requirements, and tests for active energy meters. +IEC 62052 and IEC 62053 series: Commonly applied for the functional and accuracy performance of electricity meters. +American Standards + +In the United States, the standards are developed by the American National Standards Institute (ANSI) and the Institute of Electrical and Electronics Engineers (IEEE). Key standards include: +ANSI C12 Series: Covering meter accuracy, testing, and performance for residential, commercial, and industrial meters. +IEEE 1708: Provides guidelines for testing the cybersecurity of smart meters. +Chinese Standards + +In China, electricity meter standards are governed by the China National Standards (GB), which align with international practices but also reflect specific local requirements: +GB/T 17215: Sets the requirements for static electricity meters for active energy. +DL/T 645: Specifies the communication protocol for multi-function electricity meters, ensuring interoperability. +Australian Standards + +In Australia, electricity meters adhere to the standards set by Standards Australia and the National Measurement Institute (NMI): +AS 62052.11 and AS 62053.21: Align with IEC standards for general requirements and accuracy classes of electricity meters. +NMI M 6: Specifies the metrological requirements for electricity meters used for billing. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electricity_meter-8.md b/data/en.wikipedia.org/wiki/Electricity_meter-8.md new file mode 100644 index 000000000..059a1e435 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Electricity_meter-8.md @@ -0,0 +1,31 @@ +--- +title: "Electricity meter" +chunk: 9/9 +source: "https://en.wikipedia.org/wiki/Electricity_meter" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:32.585250+00:00" +instance: "kb-cron" +--- + +== 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 transmissions. These can be used for surveillance, revealing information about peoples' possessions and behaviour. For instance, it can show when the customer is away for extended periods. Nonintrusive load monitoring gives even more detail about what appliances people have and their living and use patterns. +A more detailed and recent analysis of this issue was performed by the Illinois Security Lab. + +== See also == + +Energy management software +Energy monitoring and targeting +Meter operator +Utility submeter +Zellweger off-peak +Multimeter + +== Notes == + +== References == + +== External links == + Media related to Electricity meters (kWh) at Wikimedia Commons \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Electrophorus-0.md b/data/en.wikipedia.org/wiki/Electrophorus-0.md index 2a9a9dda1..7d77aa803 100644 --- a/data/en.wikipedia.org/wiki/Electrophorus-0.md +++ b/data/en.wikipedia.org/wiki/Electrophorus-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Electrophorus" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:36:53.319583+00:00" +date_saved: "2026-05-05T09:42:33.988574+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Electroscope-0.md b/data/en.wikipedia.org/wiki/Electroscope-0.md index 93be93f59..0d1557ca4 100644 --- a/data/en.wikipedia.org/wiki/Electroscope-0.md +++ b/data/en.wikipedia.org/wiki/Electroscope-0.md @@ -4,7 +4,7 @@ chunk: 1/2 source: "https://en.wikipedia.org/wiki/Electroscope" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:36:54.498121+00:00" +date_saved: "2026-05-05T09:42:35.181897+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Electroscope-1.md b/data/en.wikipedia.org/wiki/Electroscope-1.md index 747506a06..72af9ba11 100644 --- a/data/en.wikipedia.org/wiki/Electroscope-1.md +++ b/data/en.wikipedia.org/wiki/Electroscope-1.md @@ -4,7 +4,7 @@ chunk: 2/2 source: "https://en.wikipedia.org/wiki/Electroscope" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:36:54.498121+00:00" +date_saved: "2026-05-05T09:42:35.181897+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Galvanometer-0.md b/data/en.wikipedia.org/wiki/Galvanometer-0.md index 8a486e7a8..9d698115d 100644 --- a/data/en.wikipedia.org/wiki/Galvanometer-0.md +++ b/data/en.wikipedia.org/wiki/Galvanometer-0.md @@ -4,7 +4,7 @@ chunk: 1/4 source: "https://en.wikipedia.org/wiki/Galvanometer" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:05.190184+00:00" +date_saved: "2026-05-05T09:42:36.412179+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Galvanometer-1.md b/data/en.wikipedia.org/wiki/Galvanometer-1.md index 9d308d050..25669f9a1 100644 --- a/data/en.wikipedia.org/wiki/Galvanometer-1.md +++ b/data/en.wikipedia.org/wiki/Galvanometer-1.md @@ -4,7 +4,7 @@ chunk: 2/4 source: "https://en.wikipedia.org/wiki/Galvanometer" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:05.190184+00:00" +date_saved: "2026-05-05T09:42:36.412179+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Galvanometer-2.md b/data/en.wikipedia.org/wiki/Galvanometer-2.md index 328ba72ff..57a8c44de 100644 --- a/data/en.wikipedia.org/wiki/Galvanometer-2.md +++ b/data/en.wikipedia.org/wiki/Galvanometer-2.md @@ -4,7 +4,7 @@ chunk: 3/4 source: "https://en.wikipedia.org/wiki/Galvanometer" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:05.190184+00:00" +date_saved: "2026-05-05T09:42:36.412179+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Galvanometer-3.md b/data/en.wikipedia.org/wiki/Galvanometer-3.md index f6c6a1d2c..336fba0c1 100644 --- a/data/en.wikipedia.org/wiki/Galvanometer-3.md +++ b/data/en.wikipedia.org/wiki/Galvanometer-3.md @@ -4,7 +4,7 @@ chunk: 4/4 source: "https://en.wikipedia.org/wiki/Galvanometer" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:05.190184+00:00" +date_saved: "2026-05-05T09:42:36.412179+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Jack_B._Newton-0.md b/data/en.wikipedia.org/wiki/Jack_B._Newton-0.md new file mode 100644 index 000000000..c23f1a930 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Jack_B._Newton-0.md @@ -0,0 +1,47 @@ +--- +title: "Jack B. Newton" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Jack_B._Newton" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:33.115423+00:00" +instance: "kb-cron" +--- + +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) telescope and observatory dome in his backyard, while participating in astrophotography studies at the Winnipeg Centre of RASC where he became president from 1970-72. +His work in store management required a move to Toronto in 1973, when he began testing film types for astrophotography, including experiments with cooled emulsions and hypersensitized, gas-soaked films. This work led to publication of his first book in 1974, Astro Photography: From Film to Infinity. In 1975, he became president of the Toronto Centre of RASC for 1975-76, while maintaining his research and development of astrophotography, enabling publication in 1997 of An Introduction to CCD Astronomy and Deep Sky Objects: A Photographic Guide for the Amateur. +In 1979, Newton moved for work to Victoria, British Columbia where he joined the Victoria Centre of RASC, serving as president in 1980-81 and 1990-91. Throughout his RASC participation and in later life, he was widely regarded as a public speaker, author, and educator for astronomy and astrophotography. +From July 2000 to October 2023, Newton and his wife, Alice, provided an astronomy-themed bed and breakfast service in their home in Osoyoos, British Columbia where guests were given night and morning celestial tours – in the observatory built by Newton – using an automated 16 in (41 cm) Meade LX200 telescope under Jack's instruction. +Jack and Alice Newton are cofounders of the Arizona Sky Village, a dark-sky preserve and astronomy-oriented community in Portal, Arizona. +Jack Newton died in Oliver, British Columbia on 11 November 2025 at age 83. + +== Astrophotography == +Newton was 13 years old when he took his first astrophotograph of the planet Saturn. He pioneered "cold camera" astrophotography, chilling a film camera with dry ice, allowing for substantially longer exposures on film to enhance the details of dim, distant celestial objects. Many of his astrophotographs were published in mainstream magazines, such as the National Newsletter, Astronomy Magazine, Sky & Telescope, Newsweek, and Canadian Geographic. +In 1991, Newton became the first amateur astrophotographer to make full-color charge-coupled device (CCD) images of celestial objects using a Santa Barbara Instruments Group ST-4 camera, constructing a full-color CCD image of Messier 57, the "Ring Nebula" and Messier 27, the "Dumbbell Nebula". Newton used three separate black and white images, each with a separate filter in red, blue, and green, to construct full-color images with software being developed by Richard Berry, then editor of Astronomy Magazine. This first CCD image of the Dumbbell Nebula was published on the cover of Astronomy Magazine in February, 1992. +In 1992, Newton used his self-built 25 in (64 cm) Newtonian telescope and ST-6 CCD camera to take multiple exposures of Comet Swift–Tuttle from his home in Sooke, British Columbia, sharing the images with members of the University of Victoria Department of Physics and Astronomy for digital image processing and astrometry. In another innovation, Newton captured images of hydrogen-alpha bursts of plasma ejections from the Sun's surface using a specialized telescope filter, a facility he provided for guests to observe at the Osoyoos Observatory B&B. +Newton was a member of the Harvard University team allocated time on the Hubble Space Telescope in 2010 – and the first Canadian to use Hubble – for study of the Type Ib supernova named SN 2010O, discovered in the colliding double-galaxy NGC 3690/Arp 299. + +== Publications == + +=== Books === +Newton published books on amateur astronomy and astrophotography. + +His first, Astrophotography: From Film to Infinity, was published by the Astronomical Endeavors Publishing Company (Buffalo, NY) in 1974 (specific ISBN unavailable). +Deep Sky Objects: A Photographic Guide for the Amateur was published in 1977 by Gall Publications (Toronto) ISBN 0889040818. +An Introduction to CCD Astronomy and Deep Sky Objects: A Photographic Guide for the Amateur was published with Philip Teece as coauthor in 1977 ISBN 9780521573078. +In 1979 with Philip Teece, he published The Guide to Amateur Astronomy (1995, 2nd edition) ISBN 9780521444927. +Via Cambridge University Press and with Philip Teece as coauthor, Newton published the Cambridge Deep-Sky Album in 1984 ISBN 0521256682. +Splendors of the Universe: A Practical Guide to Photographing the Night Sky was published with Terence Dickinson as coauthor in 1997 (Firefly Press, ISBN 9781552091418). + +=== Astrophotography letters === +Published in the journal of the Royal Astronomical Society of Canada, Newton wrote short papers and letters as brief guides for amateur astronomers. + +The construction of a hydrogen-alpha solar prominence spectroscope, 1970. +General Index to the Journal 1967-1996, Royal Astronomical Society of Canada - search: "Jack Newton" \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Jack_B._Newton-1.md b/data/en.wikipedia.org/wiki/Jack_B._Newton-1.md new file mode 100644 index 000000000..eab2557a7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Jack_B._Newton-1.md @@ -0,0 +1,42 @@ +--- +title: "Jack B. Newton" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Jack_B._Newton" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:33.115423+00:00" +instance: "kb-cron" +--- + +== 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 discoveries and co-discoveries over their search history of 1994-2018, and one discovery of a cataclysmic variable star in June 2010. Named as co-discoverer of three supernovae in 2015 by the Central Bureau for Astronomical Telegrams. +2005: Carolyn S. Shoemaker and David H. Levy named an asteroid, 30840 Jackalice = 1991 GC2, in honor of Newton's astrophotographic accomplishments and for work in astronomy outreach by Jack and Alice Newton. The asteroid was last observed on 9 June 2025. +2006: Honorary membership in the Astronomical League, an American association of 330 amateur astronomy societies. +2017: Recognized with Alice Newton as an Honorary Patron of the Cotswold Astronomical Society. +Newton helped establish the astronomy program at the Lester B. Pearson College of the Pacific, Metchosin, British Columbia, in collaboration with retired faculty member and physics professor, Jean Godin; Newton donated to the institution's Newton-Godin Observatory a 25 in (64 cm) Newtonian telescope – which Newton had assembled himself – regarded for years as one of the largest private telescopes in Canada. Jack and Alice Newton served several terms as honorary patrons of the college. +Jack made solar eclipse expeditions to Oaxaca (Mexico), Baker Lake, Nunavut, Brańsk, Poland, Baja California, and Indonesia. In 1986, he led a group of 300 amateur astronomers to Peru to view Halley's Comet. + +== Documentary == +A 2023 documentary entitled, "Jack Newton's Journey to the Stars", including interviews with him, covered the history of his telescope and camera innovations. + +== Public outreach == +The devotion of Jack and his wife, Alice, by promoting astronomy education with night and day telescope sessions for guests at the Osoyoos Observatory B&B was recognized over 23 years by new and repeat visitors. +Newton's photography and writing were published in numerous issues of Astronomy magazine, in Skynews (Canada), and in Sterne und Weltraum – the journal of the German Max Planck Institute. In July 2003 and February 2009 issues, Astronomy published several of Newton's remarkable astrophotographs, calling the selections, "A mix of solar and deep-sky images taken by a master". +In 2007, one of his solar images was used for the lead-in to the science section in Life: Platinum Edition Anniversary Collection—70 Years of Extraordinary Photography (ISBN 1-933405-17-1). +His solar images appeared in National Geographic's 2004 special edition entitled Exploring Space - The Universe in Pictures, Time Inc.'s Life - the Year in Pictures (2003 and 2004), and in Sky & Telescope's 2004 Beautiful Universe issue. His astrophotographs have appeared in the Audubon Field Guide to the Night Sky, and in Nightwatch, an astronomy book by Terence Dickinson, with whom Newton co-wrote Splendors of the Universe: A Practical Guide to Photographing the Night Sky, 1997. + +=== Dark sky commitment === +Newton was active in supporting the goals of the international dark-sky movement, having such enthusiasm that he bought over 400 acres (160 ha) of remote desert land in Arizona in 2002 to create the Arizona Sky Village – a community devoted to amateur astronomy through use of personal telescopes in their own home observatories. +Maintaining a dark-sky preserve by omission of street lights, the village is one of the darkest night sky locations in the United States, having about 300 clear-sky nights per year for celestial exploration, and a single nighttime rule: turn off all lights. + +== References == + +== External links == +Lecture and astrophotography slideshow via Zoom to Kalamazoo Astronomical Society, 20 January 2023; first 45 minutes +Obituary and biography by Alan Dyer, 11 November 2025; includes 2016 video with Scott Roberts and the Meade telescope at the Observatory B&B, Osoyoos; Jack at age 74 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Leyden_jar-0.md b/data/en.wikipedia.org/wiki/Leyden_jar-0.md index cd90c567f..89c7f93af 100644 --- a/data/en.wikipedia.org/wiki/Leyden_jar-0.md +++ b/data/en.wikipedia.org/wiki/Leyden_jar-0.md @@ -4,7 +4,7 @@ chunk: 1/3 source: "https://en.wikipedia.org/wiki/Leyden_jar" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:15.662578+00:00" +date_saved: "2026-05-05T09:42:37.652328+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Leyden_jar-1.md b/data/en.wikipedia.org/wiki/Leyden_jar-1.md index 0f7ba4cc2..d9c223392 100644 --- a/data/en.wikipedia.org/wiki/Leyden_jar-1.md +++ b/data/en.wikipedia.org/wiki/Leyden_jar-1.md @@ -4,7 +4,7 @@ chunk: 2/3 source: "https://en.wikipedia.org/wiki/Leyden_jar" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:15.662578+00:00" +date_saved: "2026-05-05T09:42:37.652328+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Leyden_jar-2.md b/data/en.wikipedia.org/wiki/Leyden_jar-2.md index 9156f0bf6..758586e26 100644 --- a/data/en.wikipedia.org/wiki/Leyden_jar-2.md +++ b/data/en.wikipedia.org/wiki/Leyden_jar-2.md @@ -4,7 +4,7 @@ chunk: 3/3 source: "https://en.wikipedia.org/wiki/Leyden_jar" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:15.662578+00:00" +date_saved: "2026-05-05T09:42:37.652328+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/MASCARA-0.md b/data/en.wikipedia.org/wiki/MASCARA-0.md new file mode 100644 index 000000000..eed535836 --- /dev/null +++ b/data/en.wikipedia.org/wiki/MASCARA-0.md @@ -0,0 +1,46 @@ +--- +title: "MASCARA" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/MASCARA" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:26.019995+00:00" +instance: "kb-cron" +--- + +MASCARA (Multi-site All-Sky CAmeRA) is an exoplanet experiment by Leiden University. It has two stations, one in each hemisphere, each of which use cameras to make short exposure photographs of most of the visible sky to observe stars to a magnitude of 8.4. The Northern Hemisphere station at Roque de los Muchachos Observatory, La Palma, started observations in February 2015. The Southern Hemisphere station at La Silla Observatory, Chile, saw first light in July 2017. + + +== MASCARA-1b == + +On 17 July 2017, the discovery of MASCARA-1b, a confirmed superjovian exoplanet with a mass 3.7MJ, was reported by the survey team. MASCARA-1b is a hot Jupiter transiting its parent A-type star; its orbit is misaligned with the star's rotation. The planet was found unusually reflective for hot Jupiter with the measured geometric albedo of 0.171+0.066−0.068 and dayside temperature of 3062+66−68 K. Attempts to spectroscopically characterize its composition were failing as in 2022 due to relatively high planetary surface gravity resulting in compact atmosphere. + + +== MASCARA-2b == + +A second planet, MASCARA-2b, also known as KELT-20b, was also announced in 2017. It is a hot Jupiter orbiting an A-type star. The carbon monoxide, steam and neutral iron detection in the atmosphere of MASCARA-2b was announced in 2022. + + +== MASCARA-4b == + +A planet MASCARA-4b (also known as HD 85628 Ab) discovery was announced in 2019. It is a hot Jupiter on retrograde and slightly eccentric orbit. The planet is unusually reflective for a hot Jupiter. Hydrogen, sodium, magnesium, calcium and iron emission from planetary atmosphere was detected. + + +== MASCARA-5b == + +In 2021, a planet MASCARA-5b (more commonly known as TOI-1431 b), is an Ultra-hot Jupiter. Its dayside temperature is 2,700 K (2,427 °C), making it hotter than 40% of stars in our galaxy. The nightside temperature is 2,600 K (2,300 °C). + + +== List of discovered exoplanets == + + +== References == + + +== Papers == +G.J.J. Talens et al., The Multi-site All-Sky CAmeRA: Finding transiting exoplanets around bright (mV < 8) stars, accepted for publication in A&A arXiv:1702.03931 + + +== External links == +MASCARA website Archived 2017-08-23 at the Wayback Machine at Leiden University +MASCARA, ESO \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/MINERVA-Australis-0.md b/data/en.wikipedia.org/wiki/MINERVA-Australis-0.md new file mode 100644 index 000000000..260c89ee8 --- /dev/null +++ b/data/en.wikipedia.org/wiki/MINERVA-Australis-0.md @@ -0,0 +1,37 @@ +--- +title: "MINERVA-Australis" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/MINERVA-Australis" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:27.167557+00:00" +instance: "kb-cron" +--- + +MINERVA-Australis is a dedicated exoplanet observatory, operated by the University of Southern Queensland, in Queensland, Australia. The facility is located at USQ's Mount Kent Observatory, and saw first light in quarter two 2018. Commissioning of the telescope array and spectrograph was completed in mid-2019, and the facility was officially launched on 23 July 2019. +The facility follows the innovative model first deployed in the northern hemisphere's Miniature Exoplanet Radial Velocity Array (MINERVA), a northern hemisphere exoplanet facility located at the U.S. Fred Lawrence Whipple Observatory at Mt. Hopkins, Arizona. MINERVA-Australis is being used to perform southern hemisphere ground-based follow-up and characterisation observations of exoplanets discovered by NASA's Transiting Exoplanet Survey Satellite (TESS), which was launched in April, 2018. +The project's principal investigator is USQ astronomer Rob Wittenmyer, who leads a consortium of partners from institutions across the world (UNSW Australia; Nanjing University; University of California, Riverside; MIT; George Mason University; University of Louisville; University of Texas at Austin; University of Florida). + + +== Science objectives == +The primary mission of MINERVA-Australis is to support observations carried out by the NASA TESS spacecraft, providing dedicated follow-up and characterisation of newly discovered exoplanets. During commissioning, the facility was used to pursue targets of opportunity, and to carry out work extending the baseline of the Anglo-Australian Planet Search program. MINERVA-Australis allows researchers to obtain precise radial velocity observations for target stars, enabling the masses of planets discovered by the TESS spacecraft to be directly measured, and has recently demonstrated a radial velocity precision of approximately 1 m/s for bright stars. +In addition to providing precise velocity measurements, MINERVA-Australis also offers fast-cadence photometric observations. This facilitates follow-up transit observations of TESS candidate planets, allowing confirmation of the planet and measurement of its radius. Together, the radius and the spectroscopic mass determine a planet's density. The ephemerides from ground-based photometry and spectroscopy are a foundation for space-based observations that may establish planetary atmospheres and habitability. The resources of can be scheduled for the observation of occultation events and other transient targets of opportunity. +Observations made by the MINERVA-Australis array have contributed to the discovery of more than 13 exoplanets through collaboration with researchers at institutions across the globe. + + +== The facility == +MINERVA-Australis currently uses four PlaneWave CDK700 telescopes,. These 0.7 m telescopes have two ports, allowing each to be used for either spectroscopic or photometric observations. Each telescope sits in its own automated clam-shell Astrohaven dome, distributed in an approximate semi-circle around the main observatory building. + +The telescopes are connected by optical fibre to a stabilised, R = 75,000 echelle spectrograph, covering the wavelengths 480 - 630nm, designed by KiwiStar Optics. The spectrograph uses simultaneous calibration in a separate fibre. Prior to 2020, the simultaneous calibration was provided by a Thorium-Argon lamp. Because of the wavelength range and the very low scattered light the simultaneous calibration source is now supplied by a Tungsten slit-flat lamp backlighting an iodine cell. This is a different approach to the normal iodine cell method that passes the starlight through an iodine cell. +Photometric work is to be carried out using Andor cameras, with 2k x 2k back-illuminated CCDs with 15 μm pixels. These cameras offer an effective field of view greater than 20 arcminutes. + + +== See also == +List of telescopes of Australia + + +== References == + + +== External links == +University of Louisville and Minerva Australis at Mt. Kent \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Miniature_Exoplanet_Radial_Velocity_Array-0.md b/data/en.wikipedia.org/wiki/Miniature_Exoplanet_Radial_Velocity_Array-0.md new file mode 100644 index 000000000..2bbecea42 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Miniature_Exoplanet_Radial_Velocity_Array-0.md @@ -0,0 +1,49 @@ +--- +title: "Miniature Exoplanet Radial Velocity Array" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Miniature_Exoplanet_Radial_Velocity_Array" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:28.321581+00:00" +instance: "kb-cron" +--- + +The MINiature Exoplanet Radial Velocity Array (MINERVA) is a ground-based robotic dedicated exoplanet observatory. The facility is an array of small-aperture robotic telescopes outfitted for both photometry and high-resolution Doppler spectroscopy located at the U.S. Fred Lawrence Whipple Observatory at Mt. Hopkins, Arizona. The project's principal investigator is the American astronomer Jason Eastman. The telescopes were manufactured by PlaneWave Instruments. + + +== Science objectives == +The primary science goal of MINERVA is to discover Earth-like planets in close-in (less than 50-day) orbits around nearby stars, and super-Earths (3-15 times the mass of Earth) in the habitable zones of the closest Sun-like stars. The secondary goal is to look for transits (eclipses) of known and newly discovered extrasolar planets. The unique design of the MINERVA observatory allows the pursuit of both goals simultaneously. + + +== Specifications and status == +Telescopes: Four PlaneWave CDK700, 0.7m telescopes within 2 custom telescope enclosures designed by LCOGT engineers. One MINERVA-Red telescope +Cameras: 2k × 2k back illuminated CCD with 15 μm pixels offering > 20’ f.o.v. +Spectrograph: Stabilized, R = 75,000 echelle spectrograph with iodine cell for precise radial velocimetry designed by KiwiStar Optics (a business unit of Callaghan Innovation; a New Zealand government-owned Crown entity). +Status: Full photometric science operations began in May 2015 at FLWO. The spectrograph was installed Dec 2015. + + +== MINERVA-Red == +MINERVA-Red is an echelle spectrograph optimized for the 'deep red', between 800 nm and 900 nm (where M-dwarfs are brightest) with a robotic 0.7 meter telescope. It uses a Fabry-Perot etalon and U/Ne lamp for wavelength calibration. + + +== See also == +List of extrasolar planets + + +=== Other exoplanet search projects === + +HATNet Project (HAT) +Kilodegree Extremely Little Telescope (KELT) +Next-Generation Transit Survey (NGTS) +Trans-Atlantic Exoplanet Survey (TrES) +XO Telescope + + +== References == + + + +== External links == +Miniature Exoplanet Radial Velocity Array (MINERVA) I. Design, Commissioning, and First Science Results +Dr. John Johnson – Lecture: Exoplanetary science and Kepler mission update on YouTube (time 25:01 min.) +Minerva-Red \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Minoan_Moulds_of_Palaikastro-0.md b/data/en.wikipedia.org/wiki/Minoan_Moulds_of_Palaikastro-0.md new file mode 100644 index 000000000..7c83f5b05 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Minoan_Moulds_of_Palaikastro-0.md @@ -0,0 +1,47 @@ +--- +title: "Minoan Moulds of Palaikastro" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Minoan_Moulds_of_Palaikastro" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:29.533442+00:00" +instance: "kb-cron" +--- + +The Minoan Moulds of Palaikastro (Greek: Μήτρες του Παλαιοκάστρου Σητείας, romanized: Mitres tou Palaiokastrou Sitias) are two double-sided pieces of schist, formed in the Minoan period as casting moulds for plaques with figures and symbols. These include female figures with raised arms, labrys double axes (Λάβρυες, labryes) and opium poppy flowers or capsules, two double axes with indented edges, the Horns of Consecration symbol, and a sun-like disc with complex markings, which has been claimed by some researchers to be for making objects to use in astronomical predictions of solar and lunar eclipses. +They were found in 1899 near Palaikastro in the eastern part of Crete, and are now in the Herakleion Archeological Museum in Crete. + + +== Description == +Stefanos Xanthoudidis, who published the find in 1900 described the two moulds, which were made from relatively soft and brittle schist as Plate Α and Plate Β. His plaster casts, which are also reproduced on the right hand side, are mirror images of the original moulds. Both moulds are 225 mm (8.9 in) wide, 100 mm (3.9 in) high and 20 mm (0.8 in) thick, while the width of the plaster casts is 230 mm (9.1 in). +The front of Plate Α shows a large disc with rectangular spokes and a serrated edge (which some are keen to interpret as "geared"), a female figure with raised arms, who holds flowers in her hands and a small disc with a cross in the centre on top of a bell-shaped and horizontally striped base, above a crescent. Double horns, the 'Horns of Consecration' of the Minoan culture, and a trident are shown on the rear. A small piece of the lower edge of the mould is broken-off. +The front of Plate B shows engravings of a couple of double axes, dissimilar in size with teethed edges. The double axe or labrys was a cultural, almost certainly religious, symbol of the Minoan culture, often used for votive offerings, as were goddess figures with uplifted hands. The rear of the plate shows a female figure with raised arms holding two double axes. A small piece of the lower edge of the mould is broken-off as well. Both plates are exhibited side by side in the Heraklion Archaeological Museum. The visitors can only see their front sides. The captions in the museum say that they stem from 1370 to 1200 BCE. + + +=== Iconography === + +Very interesting objects are shown on the front of Plate Α, as recognised by Arthur Evans, who described them in his book The Palace of Minos at Knossos in 1921. On pages 478 and 479, he compares the base of an ivory object, of the Knossos board game, with the geared object on the mould of Palaikastro. On page 514 he shows drawings of the objects left and right of the female figurine of Plate Α, however, not very precisely. Evans refers to the isosceles cross being used in many cultures as the most simple representation of a star, and concludes that the geared object is a combination of a Morning Star with the disc of the sun. He interprets that the smaller object is a symbol for the goddess as the queen of the underworld and as the stars of the night. In combination with the crescent, the cross is then an Evening Star. + + +== Possible historical astronomy function == +In 2013, five scientists published a paper in the Mediterranean Archaeology and Archaeometry journal, in which they described the 85 by 85 millimetres (3.3 in × 3.3 in) sun-like form on Plate Α as a casting mould for manufacturing a spoked disc, which was used in the Minoan times of the 15th century BC as a sun dial, for establishing the geographical latitude and for predicting solar and lunar eclipses. The straight gashes beside the sun shape they interpret as moulds for two pins and a compasses or tweezers-like object, to be used in conjunction with it. They claimed to be able to predict eclipses even in the modern era with some accuracy, when using it. + +Similar comments have been made by Minas Tsikritsis in April 2011 in public. He described together with Efstratios Theodosiou the smaller round image to the right of the female figure as a Minoan cosmology model with the planetary system above the Flat Earth, in which the cross that symbolises the sun is surrounded by 18 dots and those including the crescent-shaped moon symbol are surrounded by 28 dots, an indication hinting at the Saros cycle with 28 lunar eclipses in 18 years. This is approximately 30 millimetres (1.2 in) long and 62 millimetres (2.4 in) high. They interpret the spoked disc on the other side of the female figurine, which is associated with Titaness Rhea, as a portable analog calculator, which was created 1400 years before the Antikythera mechanism. + + +== Dating == +Chronological dating of the moulds is difficult, because the precise original location of the find and its surroundings are not known. Stratigraphy or the assessment of age-equivalent stratigraphic markers are, therefore, not applicable. In 1927, Martin P. Nilsson compared the style of the female figurine of Plate Α with those on various Minoan-Mycenaean gold rings and a relief on the Hagia Triada sarcophagus. +In 1941, Luisa Banti classified both female figurines as variations of the type "goddess with raised hands", similar to the terracotta figurines found in Knossos, Gazi, Karphi and other places in Crete, which belong to the Late Minoan III phase. Stylianos Alexiou endorsed in 1958 the dating as belonging to Late Minoan III, but he noted the differences in the gesture, as the female figurines hold something in their hands. +In 2016, based on a stylistic and iconographic assessment, the casting moulds were dated as being older by Jan G. Velsink, who dates them as belonging to the Middle Minoan phases MM II or III. + + +== Discovery and publication == +The two moulds were discovered in October 1899 by a farmer from Karydi 150 m (490 ft) northeast of the village of Palaikastro. The Gendarmerie sent the finds to the then Cretan capital Chania, where they were assessed and kept by the archeologist and historian Stefanos Xanthoudidis. He recognised the importance of ancient craftsmanship and delivered the moulds to the museum in Heraklion which had been set up in 1883. Xanthoudidis described the objects in March 1900 in an article ("Ancient moulds from Sitia in Crete") in the journal of the Archaeological Society of Athens. This publication included photos of plaster casts of all four sides of the moulds. + + +== References == + + +== External links == + +"Sitia: Archaeoastronomy". Sitia Development Organisation. 2016. Retrieved 2019-03-26. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Mural_instrument-0.md b/data/en.wikipedia.org/wiki/Mural_instrument-0.md index 45fc14def..c47fbaedd 100644 --- a/data/en.wikipedia.org/wiki/Mural_instrument-0.md +++ b/data/en.wikipedia.org/wiki/Mural_instrument-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Mural_instrument" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:21.553584+00:00" +date_saved: "2026-05-05T09:41:30.773996+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/MySky-0.md b/data/en.wikipedia.org/wiki/MySky-0.md new file mode 100644 index 000000000..4db356b15 --- /dev/null +++ b/data/en.wikipedia.org/wiki/MySky-0.md @@ -0,0 +1,23 @@ +--- +title: "MySky" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/MySky" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:31.942048+00:00" +instance: "kb-cron" +--- + +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. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Next-Generation_Transit_Survey-0.md b/data/en.wikipedia.org/wiki/Next-Generation_Transit_Survey-0.md new file mode 100644 index 000000000..fd6862f57 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Next-Generation_Transit_Survey-0.md @@ -0,0 +1,30 @@ +--- +title: "Next-Generation Transit Survey" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Next-Generation_Transit_Survey" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:34.336453+00:00" +instance: "kb-cron" +--- + +The Next-Generation Transit Survey (NGTS) is a ground-based robotic search for exoplanets. The facility is located at Paranal Observatory in the Atacama Desert in northern Chile, about 2 km from ESO's Very Large Telescope and 0.5 km from the VISTA Survey Telescope. Science operations began in early 2015. The astronomical survey is managed by a consortium of seven European universities and other academic institutions from Chile, Germany, Switzerland, and the United Kingdom. Prototypes of the array were tested in 2009 and 2010 on La Palma, and from 2012 to 2014 at Geneva Observatory. +The aim of NGTS is to discover super-Earths and exo-Neptunes transiting relatively bright and nearby stars with an apparent magnitude of up to 13. The survey uses transit photometry, which precisely measures the dimming of a star to detect the presence of a planet when it crosses in front of it. NGTS consists of an array of twelve commercial 0.2-metre telescopes (f/2.8), each equipped with a red-sensitive CCD camera operating in the visible and near-infrared at 600–900 nm. The array covers an instantaneous field of view of 96 square degrees (8 deg2 per telescope) or around 0.23% of the entire sky. NGTS builds heavily on experience with SuperWASP, using more sensitive detectors, refined software, and larger optics, though having a much smaller field of view. Compared to the Kepler space telescope with its original Kepler field of 115 square degrees, the sky area covered by NGTS will be sixteen times larger, because the survey intends to scan four different fields every year over a period of four years. As a result, the sky coverage will be comparable to that of Kepler's K2 phase. +NGTS is suited to ground-based photometric follow-up of exoplanet candidates from space-based telescopes such as TESS, Gaia and PLATO. In turn, larger instruments such as HARPS, ESPRESSO and VLT-SPHERE may follow-up on NGTS discoveries with a detailed characterization to measure the mass of a large number of targets using Doppler spectroscopy (wobble method) and make it possible to determine the exoplanet's density, and hence whether it is gaseous or rocky. This detailed characterization allows to fill the gap between Earth-sized planets and gas giants as other ground-based surveys can only detect Jupiter-sized exoplanets, and Kepler's Earth-sized planets are often too far away or orbit stars too dim to allow for the planet's mass determination. NGTS's wider field of view also enables it to detect a larger number of more-massive planets around brighter stars. + +== Science mission == + +Ground-based surveys for extrasolar planets such as WASP and the HATNet Project have discovered many large exoplanets, mainly Saturn- and Jupiter-sized gas giants. Space-based missions such as CoRoT and the Kepler survey have extended the results to smaller objects, including rocky super-Earth- and Neptune-sized exoplanets. Orbiting space missions have a higher accuracy of stellar brightness measurement than is possible via ground-based measurements, but they have probed a relatively small region of sky. Unfortunately, most of the smaller candidates orbit stars that are too faint for confirmation by radial-velocity measurements. The masses of these smaller candidate planets are hence either unknown or poorly constrained, such that their bulk composition cannot be estimated. +By focusing on super-Earth- to Neptune-sized targets orbiting cool, small, but bright stars of K and early-M spectral type, over an area considerably larger than that covered by space missions, NGTS is intended to provide prime targets for further scrutiny by telescopes such as the Very Large Telescope (VLT), Extremely Large Telescope (ELT), and the James Webb Space Telescope (JWST). Such targets are more readily characterized in terms of their atmospheric composition, planetary structure, and evolution than smaller targets orbiting larger stars. +In follow-up observations by larger telescopes, powerful means will be available to probe the atmospheric composition of exoplanets discovered by NGTS. For example, during secondary eclipse, when the star occults the planet, a comparison between the in-transit and out-of-transit flux allows computation of a difference spectrum representing the thermal emission of the planet. Calculation of the transmission spectrum of the planet's atmosphere can be obtained by measuring the small spectral changes in the spectrum of the star that arise during the planet's transit. This technique requires an extremely high signal-to-noise ratio, and has thus far been successfully applied to only a few planets orbiting small, nearby, relatively bright stars, such as HD 189733 b and GJ 1214 b. NGTS is intended to greatly increase the number of planets that area analyzable using such techniques. Simulations of expected NGTS performance reveal the potential of discovering approximately 231 Neptune- and 39 super-Earth-sized planets amenable to detailed spectrographic analysis by the VLT, compared to only 21 Neptune- and 1 super-Earth-sized planets from the Kepler data. + +== Instrument == + +=== Development === +The scientific goals of the NGTS require being able to detect transits with a precision of 1 mmag at 13th magnitude. Although at ground level this level of accuracy was routinely achievable in narrow-field observations of individual objects, it was unprecedented for a wide-field survey. To achieve this goal, the designers of the NGTS instruments drew upon an extensive hardware and software heritage from the WASP project, in addition to developing many refinements in prototype systems operating on La Palma during 2009 and 2010, and at the Geneva Observatory from 2012 to 2014. + +=== Telescope array === +NGTS employs an automated array of twelve 20-centimeter f/2.8 telescopes on independent equatorial mounts and operating at orange to near-infrared wavelengths (600–900 nm). It is located at the European Southern Observatory's Paranal Observatory in Chile, a location noted for low water-vapor and excellent photometric conditions. + +=== Combined search === +The NGTS telescope project cooperates closely with ESO's large telescopes. ESO facilities available for follow-up studies include the High Accuracy Radial Velocity Planet Searcher (HARPS) at La Silla Observatory; ESPRESSO for radial-velocity measurements at the VLT; SPHERE, an adaptive optics system and coronagraphic facility at the VLT that directly images extrasolar planets; and a variety of other VLT and planned ELT instruments for atmospheric characterization. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Next-Generation_Transit_Survey-1.md b/data/en.wikipedia.org/wiki/Next-Generation_Transit_Survey-1.md new file mode 100644 index 000000000..c16b8e165 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Next-Generation_Transit_Survey-1.md @@ -0,0 +1,60 @@ +--- +title: "Next-Generation Transit Survey" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Next-Generation_Transit_Survey" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:34.336453+00:00" +instance: "kb-cron" +--- + +== Partnership == +Although located at Paranal Observatory, NGTS is not in fact operated by ESO, but by a consortium of seven academic institutions from Chile, Germany, Switzerland, and the United Kingdom: + +DLR, Institute for Planetary Research +Geneva Observatory +Queen's University Belfast +University of Cambridge +University of Chile +University of Leicester +University of Warwick + +== Results == +On 31 October 2017, the discovery of NGTS-1b, a confirmed hot Jupiter-sized extrasolar planet orbiting NGTS-1, an M-dwarf star, about half the mass and radius of the Sun, every 2.65 days, was reported by the survey team. Daniel Bayliss, of the University of Warwick, and lead author of the study describing the discovery of NGTS-1b, stated, "The discovery of NGTS-1b was a complete surprise to us—such massive planets were not thought to exist around such small stars – importantly, our challenge now is to find out how common these types of planets are in the Galaxy, and with the new Next-Generation Transit Survey facility we are well-placed to do just that." +On 3 September 2018, the discovery of NGTS-4b, a sub-Neptune-sized planet transiting a 13th magnitude K-dwarf in a 1.34 day orbit. NGTS-4b has a mass 20.6 ± 3.0 M🜨 and radius 3.18 ± 0.26 R🜨, which places it well within the so-called "Neptunian desert". The mean density of the planet (3.45 ± 0.95 g cm−3) is consistent with a composition of 100% H2O or a rocky core with a volatile envelope. + +== Discoveries == + +=== Planets === +This is a list of planets discovered by this survey. This list is incomplete, and requires more information. + +=== Brown dwarfs === +In addition, the survey has discovered three brown dwarfs. + +== See also == +List of extrasolar planets + +=== Other exoplanet search projects === + +HATNet Project (HAT) +Miniature Exoplanet Radial Velocity Array (MINERVA) +Kilodegree Extremely Little Telescope (KELT) +Trans-Atlantic Exoplanet Survey (TrES) +Wide Angle Search for Planets (WASP and SuperWASP) +XO Telescope +Microlensing Observations in Astrophysics (MOA) +Optical Gravitational Lensing Experiment (OGLE) +Anglo-Australian Planet Search (AAPS) +Cool Companions on Ultrawide Orbits (COCONUTS) +Transiting Planets and Planetesimals Small Telescope (TRAPPIST) +Search for Habitable Planets Eclipsing Ultra-cool Stars (SPECULOOS) + +== Notes == + +== References == + + +== External links == +Official website + Media related to Next-Generation Transit Survey at Wikimedia Commons +The Next Generation Transit Survey Becomes Operational at Paranal, ESO archive, The Messenger 165 – September 2016 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Nocturnal_(instrument)-0.md b/data/en.wikipedia.org/wiki/Nocturnal_(instrument)-0.md index 7d888f78a..aa091915a 100644 --- a/data/en.wikipedia.org/wiki/Nocturnal_(instrument)-0.md +++ b/data/en.wikipedia.org/wiki/Nocturnal_(instrument)-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Nocturnal_(instrument)" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:23.952358+00:00" +date_saved: "2026-05-05T09:41:35.530245+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-0.md b/data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-0.md new file mode 100644 index 000000000..15bd937cd --- /dev/null +++ b/data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-0.md @@ -0,0 +1,26 @@ +--- +title: "Noyes Armillary Sphere" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Noyes_Armillary_Sphere" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:36.693155+00:00" +instance: "kb-cron" +--- + +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 National Park Service (NPS) and placed in a storage facility, where it was either stolen or misplaced. In 2018, the NPS announced an exact replica would be installed in the park. Using old drawings and photographs, Kreilick Conservation LLC created the new sphere which was installed in 2024. + +== History == + +=== Planning === +Meridian Hill Park is a 12-acre (4.9 ha) urban park in Washington, D.C., located between 15th, 16th, Euclid, and W Streets NW. It was built between 1914 and 1936 as part of the City Beautiful movement and at the behest of Mary Foote Henderson, an activist and real estate developer whose mansion overlooked the park. The park was originally planned by landscape architect George Burnap, but after he left the project, architect Horace Peaslee oversaw its completion. Plans for the park included spaces for public art installations. During the 1920s, the Dante Alighieri, Joan of Arc, and Serenity statues were dedicated. A fourth installation, a memorial to President James Buchanan, was dedicated in 1930. +Plans for a fifth art installation in the park was headed by Charles Moore, a city planner who served as chairman of the United States Commission of Fine Arts (CFA) from 1915 to 1937. Inspired by Paul Manship's Cochran Armillary located on the campus of Phillips Academy in Massachusetts, CFA member and landscape architect Ferruccio Vitale suggested an armillary sphere be installed on the southern end of the park, below the Cascading Waterfall and reflecting pool. Chinese astronomers invented armillary spheres around 200 BC. The spheres map celestial objects by using rings to represent principal circles of the heavens. +After Moore was informed of the estimated $30,000 cost of Manship's design, the commission was given to sculptor C. Paul Jennewein, whose design was based on the one by Manship. Examples of Jennewein's works in Washington, D.C., are the Darlington Memorial Fountain in Judiciary Square, 57 sculptural elements at the Robert F. Kennedy Department of Justice Building, and two statues at the Rayburn House Office Building. Peaslee was selected to design the sphere's pedestal. Artist Bertha Noyes paid $15,000 of the project cost in memory of her sister, Edith Noyes, who was an invalid and had died in 1925. + +=== Production and installation === + +By 1931, Jennewein had completed sculpting the sphere. Due to a limited budget, Jennewein's suggestion that the bronze sculpture be fire gilded and "burnished to a bright color" did not occur. Following its passage in the United States House of Representatives, a resolution to accept the sculpture on behalf of the country was passed by the United States Senate Committee on Public Buildings and Grounds on May 12, 1932. After Congress passed the final bill on June 10, 1932, to accept the sculpture and approve its location, President Herbert Hoover signed the bill into law. In December 1933, CFA members traveled to Brooklyn to assess the sculpture's progress at the Roman Bronze Works company. The founding process had taken 14 months and cost $2,800. Although the sphere was ready to be transported to Washington, D.C., there were delays in installing the foundation at the park and the sphere remained in New York. +It wasn't until spring 1935 that the foundation was installed, followed by the sphere a few months later. The total cost of the project was $31,199. Work continued on the sphere through the following year. After the inscription "Given to the Federal City, MCMXXXVI, for Edith Noyes" was engraved, the sphere was dedicated[1] on November 10, 1936. A bronze calibration plaque, located on a cast iron post by the sphere, was later installed to correct errors with time precision. Decorative armillary spheres were added on top of the wrought-iron fence located on the north end of the park. + +=== Removal and replacement === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-1.md b/data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-1.md new file mode 100644 index 000000000..70e15195f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Noyes_Armillary_Sphere-1.md @@ -0,0 +1,23 @@ +--- +title: "Noyes Armillary Sphere" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Noyes_Armillary_Sphere" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:36.693155+00:00" +instance: "kb-cron" +--- + +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, and a few years later, a NPS employee suggested a facsimile be made. The estimated cost of this replica was between $48,000 and $90,000, but due to a lack of funding, the plan did not come to fruition at that time. In the 1990s, NPS official John Parsons offered support for a replica "on its original base to the exact historic scale, design, and specifications". It wasn't until 2004 that a full-scale aluminum mock-up costing $8,840 was made. It too was placed in a Maryland storage facility because the aluminum would have been unsuitable for inclement weather. The NPS announced in 2018 that restorations would be made to Meridian Hill Park beginning the following year. One of these improvements would be a replica of the sphere being installed thanks to a donation by Roger and Susan Gendron. Based on original drawings and photographs of the sphere, Kreilick Conservation LLC used techniques including computer numerical control and 3D modeling to create a replica. The new sphere was installed in November 2024. + +== Location and design == +The sphere is located in the park's exedra, south of the Cascading Waterfall and reflecting pool. It stands on the Washington meridian that passes through the White House. A wrought iron fence and bushes surround the sphere. It rests on an octagonal green granite pedestal which is 3 ft 4 in (1.02 m) tall and features heavy molding. The sphere measures 6 ft 6 in (1.98 m) tall, 5 ft 5 in (1.65 m) wide, and 17 ft 9 in (5.41 m) in circumference. It weighs[2] between 1,250 pounds (570 kg) and 1,500 pounds (680 kg). The sculpture's pedestal features a bronze putto called "Child Greeting the Sun". The winged figure, which is around 18 in (0.46 m) tall and faces south, represents the "birth of each new day". The bronze sphere resembles a celestial globe and is composed of rings inscribed with reliefs. The two largest rings represent the Meridian and Equator. The equatorial ring features reliefs of astrological signs on the exterior. On the interior are stars representing nighttime hours and Roman numerals representing hours of the day. A third ring represents the ecliptic plane and intersects with the larger rings. There is a small ring on both the north and south sides of the sphere, representing the North and South Poles. A gnomon arrow that is facing north represents the Earth's axis and casts a shadow on the equatorial ring, allowing visitors to know the local time. + +== See also == +List of public art in Washington, D.C., Ward 1 +Outdoor sculpture in Washington, D.C. + +== Notes == + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Null_detector-0.md b/data/en.wikipedia.org/wiki/Null_detector-0.md index ae3a32a0f..45cdc4ca2 100644 --- a/data/en.wikipedia.org/wiki/Null_detector-0.md +++ b/data/en.wikipedia.org/wiki/Null_detector-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Null_detector" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:26.301969+00:00" +date_saved: "2026-05-05T09:42:38.873146+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Octant_(instrument)-0.md b/data/en.wikipedia.org/wiki/Octant_(instrument)-0.md new file mode 100644 index 000000000..a02a5f482 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Octant_(instrument)-0.md @@ -0,0 +1,36 @@ +--- +title: "Octant (instrument)" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Octant_(instrument)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:37.963064+00:00" +instance: "kb-cron" +--- + +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 window prior to it being published by the Royal Society in 1742. +Newton's instrument used two mirrors, but they were used in an arrangement somewhat different from the two mirrors found in modern octants and sextants. The diagram on the right shows the configuration of the instrument. His design was the first to use two mirrors, with it significantly improving the accuracy of measurements as it provided a stable view of both the horizon and the celestial body simultaneously. +The 45° arc of the instrument (PQ), was graduated with 90 divisions of a half-degree each. Each such division was subdivided into 60 parts and each part further divided into sixths. This results in the arc being marked in degrees, minutes and sixths of a minute (10 seconds). Thus the instrument could have readings interpolated to 5 seconds of arc. This fineness of graduation is only possible due to the large size of the instrument - the sighting telescope alone was three to four feet long. +A sighting telescope (AB), three or four feet long, was mounted along one side of the instrument. A horizon mirror was fixed at a 45° angle in front of the telescope's objective lens (G). This mirror was small enough to allow the observer to see the image in the mirror on one side and to see directly ahead on the other. The index arm (CD) held an index mirror (H), also at 45° to the edge of the index arm. The reflective sides of the two mirrors nominally faced each other, so that the image seen in the first mirror is that reflected from the second. + +With the two mirrors parallel, the index reads 0°. The view through the telescope sees directly ahead on one side and the view from the mirror G sees the same image reflected from mirror H (see detail drawing to the right). When the index arm is moved from zero to a large value, the index mirror reflects an image that is in a direction away from the direct line of sight. As the index arm movement increases, the line of sight for the index mirror moves toward S (to the right in the detail image). This shows a slight deficiency with this mirror arrangement. The horizon mirror will block the view of the index mirror at angles approaching 90°. +The length of the sighting telescope seems remarkable, given the small size of the telescopes on modern instruments. This was likely Newton's choice of a way to reduce chromatic aberrations. Short–focal length telescopes, prior to the development of achromatic lenses, produced an objectionable degree of aberration, so much so that it could affect the perception of a star's position. Long focal lengths were the solution, and this telescope would likely have had both a long–focal length objective lens and a long–focal length eyepiece. This would decrease aberrations without excessive magnification. + +=== The inventors of the octant === +Two men independently developed the octant around 1730: John Hadley (1682–1744), an English mathematician, and Thomas Godfrey (1704–1749), a glazier in Philadelphia. While both have a legitimate and equal claim to the invention, Hadley generally gets the greater share of the credit. This reflects the central role that London and the Royal Society played in the history of scientific instruments in the eighteenth century. +Two others who created octants during this period were Caleb Smith, an English insurance broker with a strong interest in astronomy (in 1734), and Jean-Paul Fouchy, a mathematics professor and astronomer in France (in 1732). + +=== Hadley's versions === + +Hadley produced two versions of the reflecting quadrant. Only the second is well known and is the familiar octant. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Octant_(instrument)-1.md b/data/en.wikipedia.org/wiki/Octant_(instrument)-1.md new file mode 100644 index 000000000..857c3340b --- /dev/null +++ b/data/en.wikipedia.org/wiki/Octant_(instrument)-1.md @@ -0,0 +1,37 @@ +--- +title: "Octant (instrument)" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Octant_(instrument)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:37.963064+00:00" +instance: "kb-cron" +--- + +==== 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 to reveal any object up to 90° from the direct line of sight. When both objects are in the same view, aligning them together allows the navigator to measure the angular distance between them. +Very few of the original reflecting quadrant designs were ever produced. One, constructed by Baradelle, is in the collection of the Musée de la Marine, Paris. + +==== Hadley's octant ==== + +Hadley's second design had the form familiar to modern navigators. The image to the right, also taken from his Royal Society publication, shows the details. +He placed an index mirror on the index arm. Two horizon mirrors were provided. The upper mirror, in the line of the sighting telescope, was small enough to allow the telescope to see directly ahead as well as seeing the reflected view. The reflected view was that of the light from the index mirror. As in the previous instrument, the arrangement of the mirrors allowed the observer to simultaneously see an object straight ahead and to see one reflected in the index mirror to the horizon mirror and then into the telescope. Moving the index arm allowed the navigator to see any object within 90° of the direct view. +The significant difference with this design was that the mirrors allowed the instrument to be held vertically rather than horizontally and it provided more room for configuring the mirrors without suffering from mutual interference. +The second horizon mirror was an interesting innovation. The telescope was removable. It could be remounted so that the telescope viewed the second horizon mirror from the opposite side of the frame. By mounting the two horizon mirrors at right angles to each other and permitting the movement of the telescope, the navigator could measure angles from 0 to 90° with one horizon mirror and from 90° to 180° with the other. This made the instrument very versatile. For unknown reasons, this feature was not implemented on octants in general use. +Comparing this instrument to the photo of a typical octant at the top of the article, one can see that the only significant differences in the more modern design are: + +The location of the horizon mirror and telescope or sighting pinnula is lower. +The internal bracing of the frame is more central and robust. +The position of the shades for the index mirror is in the path between the index and horizon mirrors rather than at the top of the instrument. +Multiple shades are used to allow for different levels of shading. +Separate shades are provided on the horizon mirror for sighting a low sun position with a very bright horizon. +The second horizon mirror and accompanying alidade is not provided. + +=== Smith's Astroscope === + +Caleb Smith, an English insurance broker with a strong interest in astronomy, had created an octant in 1734. He called it an Astroscope or Sea-Quadrant. His used a fixed prism in addition to an index mirror to provide reflective elements. Prisms provide advantages over mirrors in an era when polished speculum metal mirrors were inferior and both the silvering of a mirror and the production of glass with flat, parallel surfaces was difficult. +In the drawing to the right, the horizon element (B) could be a mirror or a prism. On the index arm, the index mirror (A) rotated with the arm. A sighting telescope was mounted on the frame (C). The index did not use a vernier or other device at the scale (D). Smith called the instrument's index arm a label, in the manner of Elton for his mariner's quadrant. +Various design elements of Smith's instrument made it inferior to Hadley's octant and it was not used significantly. For example, one problem with the Astroscope was that angle of the observer's line of sight. By looking down, he had greater difficulty in observing than an orientation with his head in a normal orientation. + +== Advantages of the octant == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Octant_(instrument)-2.md b/data/en.wikipedia.org/wiki/Octant_(instrument)-2.md new file mode 100644 index 000000000..18a852b0c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Octant_(instrument)-2.md @@ -0,0 +1,49 @@ +--- +title: "Octant (instrument)" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Octant_(instrument)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:37.963064+00:00" +instance: "kb-cron" +--- + +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 techniques improved, glass mirrors began to be provided. These used coatings of mercury-containing tin amalgam; coatings of silver or aluminum were not available until the 19th century. The poor optical quality of the early polished speculum metal mirrors meant that telescopic sights were not practical. For that reason, most early octants employed a simple naked-eye sighting pinnula instead. + +Early octants retained some of the features common to backstaves, such as transversals on the scale. However, as engraved, they showed the instrument to have an apparent accuracy of only two minutes of arc while the backstaff appeared to be accurate to one minute. The use of the vernier scale allowed the scale to be read to one minute, so improved the marketability of the instrument. This and the ease in making verniers compared to transversals, lead to adoption of the vernier on octants produced later in the 18th century. +Octants were produced in large numbers. In wood and ivory, their relatively low price compared to an all-brass sextant made them a popular instrument. The design was standardized with many manufacturers using the identical frame style and components. Different shops could make different components, with woodworkers specializing in frames and others in the brass components. For example, Spencer, Browning and Rust, a manufacturer of scientific instruments in England from 1787 to 1840 (operating as Spencer, Browning and Co. after 1840) used a Ramsden dividing engine to produce graduated scales in ivory. These were widely used by others and the SBR initials could be found on octants from many other manufacturers. +Examples of these very similar octants are in the photos in this article. The image at the top is essentially the same instrument as the one in the detail photos. However, they are from two different instrument makers - the upper is labelled Crichton - London, Sold by J Berry Aberdeen while the detail images are of an instrument from Spencer, Browning & Co. London. The only obvious difference is the presence of horizon shades on the Crichton octant that are not on the other. + +These octants were available with many options. A basic octant with graduations directly on the wood frame were least expensive. These dispensed with a telescopic sight, using a single- or double-holed sighting pinnula instead. Ivory scales would increase the price, as would the use of a brass index arm or a vernier. + +== Demise of the octant == +In 1767 the first edition of The Nautical Almanac tabulated lunar distances, enabling navigators to find the current time from the angle between the Sun and the Moon. This angle is sometimes larger than 90°, and thus not possible to measure with an octant. For that reason, Admiral John Campbell, who conducted shipboard experiments with the lunar distance method, suggested a larger instrument and the sextant was developed. +From that time onward, the sextant was the instrument that experienced significant development and improvements and was the instrument of choice for naval navigators. The octant continued to be produced well into the 19th century, though it was generally a less accurate and less expensive instrument. The lower price of the octant, including versions without telescope, made it a practical instrument for ships in the merchant and fishing fleets. +One common practice among navigators up to the late nineteenth century was to use both a sextant and an octant. The sextant was used with great care and only for lunars, while the octant was used for routine meridional altitude measurements of the Sun every day. This protected the very accurate and pricier sextant, while using the more affordable octant where it performs well. + +== Bubble octant == + +From the early 1930s through the end of the 1950s, several types of civilian and military bubble octant instruments were produced for use aboard aircraft. All were fitted with an artificial horizon in the form of a bubble, which was centered to align the horizon for a navigator flying thousands of feet above the Earth; some had recording features. + +== Use and adjustment == +Use and adjustment of the octant is essentially identical to the navigator's sextant. + +== Other reflecting instruments == + +Hadley's was not the first reflecting quadrant. Robert Hooke invented a reflecting quadrant in 1684 and had written about the concept as early as 1666. Hooke's was a single-reflecting instrument. Edmond Halley also designed a reflecting quadrant in 1692, though it is unlikely that he constructed it. Other octants were developed by Jean-Paul Fouchy and Caleb Smith in the early 1730s, however, these did not become significant in the history of navigation instruments. + +== See also == +List of astronomical instruments +Octant (plane geometry) + +== References == + +== External links == + Media related to Octants at Wikimedia Commons \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Optical_instrument-0.md b/data/en.wikipedia.org/wiki/Optical_instrument-0.md new file mode 100644 index 000000000..f2cda8e9f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Optical_instrument-0.md @@ -0,0 +1,48 @@ +--- +title: "Optical instrument" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Optical_instrument" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:42.800539+00:00" +instance: "kb-cron" +--- + +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 chemical or material analysis +Autocollimator which is used to measure angular deflections +Vertometer which is used to determine refractive power of lenses such as glasses, contact lenses and magnifier lens +DNA sequencers can be considered optical instruments, as they analyse the color and intensity of the light emitted by a fluorochrome attached to a specific nucleotide of a DNA strand. +Surface plasmon resonance-based instruments use refractometry to measure and analyze biomolecular interactions. + + +== Other types == +Magic lantern +Polarization controller + + +== See also == +Scientific instruments + + +== References == + + +== External links == + Media related to Optical instruments at Wikimedia Commons +Carboni, Giorgio. "From Lenses to Optical Instruments". Fun Science Gallery. Archived from the original on 30 July 2020. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Optical_mount-0.md b/data/en.wikipedia.org/wiki/Optical_mount-0.md new file mode 100644 index 000000000..ea8f4415c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Optical_mount-0.md @@ -0,0 +1,15 @@ +--- +title: "Optical mount" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Optical_mount" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:39.127815+00:00" +instance: "kb-cron" +--- + +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 == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Orrery-0.md b/data/en.wikipedia.org/wiki/Orrery-0.md index 360487cdd..ff3560e8b 100644 --- a/data/en.wikipedia.org/wiki/Orrery-0.md +++ b/data/en.wikipedia.org/wiki/Orrery-0.md @@ -4,7 +4,7 @@ chunk: 1/3 source: "https://en.wikipedia.org/wiki/Orrery" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:28.640506+00:00" +date_saved: "2026-05-05T09:41:40.330710+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Orrery-1.md b/data/en.wikipedia.org/wiki/Orrery-1.md index c648b2b6b..2cbdb5f08 100644 --- a/data/en.wikipedia.org/wiki/Orrery-1.md +++ b/data/en.wikipedia.org/wiki/Orrery-1.md @@ -4,7 +4,7 @@ chunk: 2/3 source: "https://en.wikipedia.org/wiki/Orrery" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:28.640506+00:00" +date_saved: "2026-05-05T09:41:40.330710+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Orrery-2.md b/data/en.wikipedia.org/wiki/Orrery-2.md index 1b3164474..be823f473 100644 --- a/data/en.wikipedia.org/wiki/Orrery-2.md +++ b/data/en.wikipedia.org/wiki/Orrery-2.md @@ -4,7 +4,7 @@ chunk: 3/3 source: "https://en.wikipedia.org/wiki/Orrery" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:28.640506+00:00" +date_saved: "2026-05-05T09:41:40.330710+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/POlarization_Emission_of_Millimeter_Activity_at_the_Sun-0.md b/data/en.wikipedia.org/wiki/POlarization_Emission_of_Millimeter_Activity_at_the_Sun-0.md new file mode 100644 index 000000000..734b2e25e --- /dev/null +++ b/data/en.wikipedia.org/wiki/POlarization_Emission_of_Millimeter_Activity_at_the_Sun-0.md @@ -0,0 +1,35 @@ +--- +title: "POlarization Emission of Millimeter Activity at the Sun" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/POlarization_Emission_of_Millimeter_Activity_at_the_Sun" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:44.966061+00:00" +instance: "kb-cron" +--- + +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 than 1 mm) wavelength observations of the solar activity. There are a number of different instruments around the world that monitors the sun at microwaves. The Nobeyama Radio Heliograph (NoRH) (Nobeyama, Japan) makes daily maps at 17 GHz (1.7 cm) with circular left and right polarizations and 34 GHz (8.8 mm), total intensity. The Nobeyama Radio Polarimeters (NoRP), (Nobeyama, Japan) is a set of patrol telescopes with receivers from 1 GHz (λ≈30 cm) to 80 GHz (λ≈3.7 mm) at selected frequencies and circular polarization detection (except at 80 GHz) with full sun disk spatial resolution. The Radio Solar Telescope Network (RSTN) is worldwide network of telescopes with receivers at selected bands from few hundred MHz (λ≈75 cm) to 15.4 GHz (λ≈2 cm). At the other end of the band, the Solar Submillimeter Telescope (SST) installed at Complejo Astronomico El Leoncito in San Juan Province, Argentina observes the sun at 212 GHz (λ≈1.4 mm) and 405 GHz (λ≈0.7 mm). Since there is no observational time overlap between Japan and Argentina, the NoRH and NoRP cannot be used together with SST, and only data from some RSTN observatories have times in common with the SST. +The relevance of observing at 45 and 90 GHz comes from the necessity to determine the upturn frequency in the so-called THz events: if the main radiation mechanism is synchrotron radiation from accelerated electrons emitting at chromospheric or coronal heights, it is expected a spectrum with a long and descending logarithmic tail towards millimeter wavelengths. In some cases this classical (textbook) shape is broken and an upturn or spectral reversion is observed. Since the reversion or upturn frequency has been estimated around 50 to 100 GHz for the observed cases, the importance of POEMAS is justified. + + +== See also == +Sun +Chromosphere +Corona +Solar Flares +Radio astronomy +List of radio telescopes +Synchrotron radiation + + +== References == + + +== External links == +Nobeyama Radio Heliograph Official Site +Nobeyama Radio Polarimeters Official Site +Solar Submillimeter Telescope Official Site \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Parallactic_instrument_of_Kapteyn-0.md b/data/en.wikipedia.org/wiki/Parallactic_instrument_of_Kapteyn-0.md new file mode 100644 index 000000000..9f06497ed --- /dev/null +++ b/data/en.wikipedia.org/wiki/Parallactic_instrument_of_Kapteyn-0.md @@ -0,0 +1,67 @@ +--- +title: "Parallactic instrument of Kapteyn" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Parallactic_instrument_of_Kapteyn" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:41.513041+00:00" +instance: "kb-cron" +--- + +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 lens at a star, estimating the diameter of the star, and reading the declination. +Reading the right ascension using a small microscope. +Writing down the results, as told to him by the other researchers. +To use the instrument, the researcher must look through the ocular (part J), and aim the lens (H) at a glass plate photo (see drawing). The distance between the center point of the instrument and the plate to be measured must be the same distance as the focal length of the telescope that was used to take the photos (in the case of Gill's photos: 54 inches (140 cm). By rotating the right axis (B) the researcher can aim the lens at a star of interest. The researcher can read the position of the star on the wheel (D) below the right axis (B). Similarly, parts A and C can be used to determine the right ascension. Part L is no longer on the instrument. Using this smaller telescope the researcher could correctly position the instrument in relation to the glass plate photo. +For each position on the sky, Kapteyn used two photos (each made on a different night). He placed these photos in sequence (with approximately 1 millimeter of space in between), with one being slightly displaced. This allowed him to easily distinguish stars from dust particles on the glass plate. + + +== Use by Kapteyn == +Kapteyn and his staff members analyzed the first photo (aimed at the South Pole) on October 28, 1886, and the final photo (aimed at 85° declination) on June 9, 1887. They used in the instrument in a laboratory of Dirk Huizinga, a professor in physiology who made two of his rooms available to them. Kapteyn and his staff members analyzed the glass plate photos in duplicate and darkened the room to get a better view of details in the photos. +Kapteyn and his staff performed some repeat measurements in 1892, 1896, 1897 and 1892. +Kapteyn and Gill published their Durchmusterung in three volumes that together formed the Cape Photographic Durchmusterung: declination zones -18° to -37° (1896), -38° to -52° (1897) and -53° to -89° (1900). + + +=== Influence on the private life of Kapteyn === +Working with the instrument had a significant impact on the health and private life of Kapteyn. Kapteyn often felt pain in his eyes and stomach and became easily agitated due to the intense labor. +After completing one of the last measurements, Kapteyn wrote to Gill: "...- and the truth is that I find my patience nearly exhausted", with which he referred to the analysis for the Cape Photographic Durchmusterung. +Additionally, Kapteyn wrote about working on the Durchmusterung: "There is a sort of fate that which makes me do my life long just what I want to do least of all." + + +=== Prisoners === +The British astronomer Arthur Stanley Eddington claimed that prisoners were part of the staff of Kapteyn that worked with his instrument. However, this fact is deemed implausible, since prisoners only performed relatively simple tasks in this time period and because this fact was never brought up in any correspondence with Kapteyn. + + +== Impact == +The publication of the measurements performed with the instrument of Kapteyn marked a major breakthrough for Kapteyn in the field of astronomy. In 1901 Kapteyn was the first Dutchman to receive a golden medal from the British Royal Astronomical Society. Kapteyn had been a member of this organisation since 1892. Furthermore, working with the instrument may have inspired the theories of Kapteyn about the shape of the Milky Way. Kapteyn first discussed these theories in 1891 during a rectorial speech. +The American astronomer Simon Newcomb praised Kapteyn and his work: "This work [the Cape Photographic Durchmusterung] of Kapteyn offers a remarkable example of the spirit which animates the born investigator of the heavens." +Jacob Halm remarked that the results of the Cape Photographic Durchmusterung had an accuracy comparable to that of the results of the northern hemisphere. The astronomer Henry Sawerthal, who visited the laboratory of Kapteyn in 1889, described the results as "...sufficient in the present instance to give results more accurate than those of the Northern Durchmusterung, a remark which not only applies to positions, but to magnitude (also)." +The German astronomer Max Wolf had such admiration for the instrument of Kapteyn that he built his own 'improved' version of the instrument. + + +== See also == +Jacobus Kapteyn +Kapteyn's Star (discovered with this instrument in 1897) +Durchmusterung +David Gill (astronomer) +Triquetrum (astronomy) +University museum of Groningen (Dutch Wikipedia) + + +== Further reading == +van der Kruit, Piet C.; van Berkel, Klaas (2012). The Legacy of J.C. Kapteyn: Studies on Kapteyn and the Development of Modern Astronomy. Springer. ISBN 9789401098649. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Planisphere-0.md b/data/en.wikipedia.org/wiki/Planisphere-0.md new file mode 100644 index 000000000..b97a044c9 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Planisphere-0.md @@ -0,0 +1,28 @@ +--- +title: "Planisphere" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Planisphere" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:42.676444+00:00" +instance: "kb-cron" +--- + +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 latitude. A planisphere window is designed for a particular latitude and will be accurate enough for a certain band either side of that. Planisphere makers will usually offer them in a number of versions for different latitudes. Planispheres only show the stars visible from the observer's latitude; stars below the horizon are not included. +A complete twenty-four-hour time cycle is marked on the rim of the overlay. A full twelve months of calendar dates are marked on the rim of the starchart. The window is marked to show the direction of the eastern and western horizons. The disk and overlay are adjusted so that the observer's local time of day on the overlay corresponds to that day's date on the star chart disc. The portion of the star chart visible in the window then represents (with a distortion because it is a flat surface representing a spherical volume) the distribution of stars in the sky at that moment for the planisphere's designed location. Users hold the planisphere above their head with the eastern and western horizons correctly aligned to match the chart to actual star positions. + +== History == + +The word planisphere (Latin planisphaerium) was originally used in the second century by Claudius Ptolemy to describe the representation of a spherical Earth by a map drawn in the plane. +This usage continued into the Renaissance: for example Gerardus Mercator described his 1569 world map as a planisphere. +In this article the word describes the representation of the star-filled celestial sphere on a flat disc. +The first star chart to have the name "planisphere" was made in 1624 by Jacob Bartsch. +Bartsch was the son-in-law of Johannes Kepler, discoverer of Kepler's laws of planetary motion. + +== The star chart == +Since the planisphere shows the celestial sphere in a printed flat, there is always considerable distortion. Planispheres, like all charts, are made using a certain projection method. For planispheres there are two major methods in use, leaving the choice with the designer. One such method is the polar azimuthal equidistant projection. Using this projection the sky is charted centered on one of the celestial poles (polar), while circles of equal declination (for instance 60°, 30°, 0° (the celestial equator), −30°, and −60°) lie equidistant from each other and from the poles (equidistant). The shapes of the constellations are proportionally correct in a straight line from the centre outwards, but at right angles to this direction (parallel to the declination circles) there is considerable distortion. That distortion will be worse as the distance to the pole gets greater. If we study the famous constellation of Orion in this projection and compare this to the real Orion, we can clearly see this distortion. One notable planisphere using azimuthal equidistant projection addresses this issue by printing a northern view on one side and the southern view on the other, thus reducing the distance charted from the center outward. +The stereographic projection solves this problem while introducing another. Using this projection the distances between the declination circles are enlarged in such a way that the shapes of the constellations remain correct. Naturally in this projection the constellations on the edge become too large in comparison to constellations near the celestial pole: Orion will be twice as high as it should be. (This is the same effect that makes Greenland so huge in Mercator maps.) Another disadvantage is that, with more space for constellations near the edge of the planisphere, the space for the constellations around the celestial pole in question will be less than they deserve. For observers at moderate latitudes, who can see the sky near the celestial pole of their hemisphere better than that nearer the horizon, this may be a good reason to prefer a planisphere made with the polar azimuthal equidistant projection method. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Planisphere-1.md b/data/en.wikipedia.org/wiki/Planisphere-1.md new file mode 100644 index 000000000..2859bacb3 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Planisphere-1.md @@ -0,0 +1,38 @@ +--- +title: "Planisphere" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Planisphere" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:42.676444+00:00" +instance: "kb-cron" +--- + +== 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 hills, woods, buildings or just because of the thickness of the atmosphere we look through. The lower 5° above the horizon in particular hardly shows any stars (let alone objects) except under the very best conditions. Therefore, a planisphere can fairly accurately be used from +5° to −5° of the design latitude. For example, a planisphere for 40° north can be used between 35° and 45° north. + +== Coordinates == +Accurate planispheres represent the celestial coordinates: right ascension and declination. The changing positions of planets, asteroids or comets in terms of these coordinates can be looked up in annual astronomical guides, and these enable planisphere users to find them in the sky. +Some planispheres use a separate pointer for the declination, using the same pivot point as the upper disc. Some planispheres have a declination feature printed on the upper disc, along the line connecting north and south on the horizon. Right ascension is represented on the edge, where the dates with which to set the planisphere are also found. + +== See also == +Celestial globe - the representation of the starry sky on an apparent celestial sphere. +List of astronomical instruments +Armillary sphere - a framework of brass rings, which represent the principal circles of the heavens. +Volvelle + +== References == + +== External links == +Bartsch, Jacob. Usus Astronomicus Planisphaerii Stellati, 1624. (Scans by Felice Stoppa.) The first cartographic use of the term planisphere. +Uncle Al's Sky Wheel – northern hemisphere planisphere. +Southern Star Wheel – southern hemisphere planisphere. +Toshimi Taki's planisphere – double-sided planisphere mainly for equatorial areas. +Astronomy in Your Hands - create your planisphere customized to any latitude/longitude in the globe. +Printable planispheres for every 10° of latitude up to 60° +Planisphere — explore the night sky, printable planisphere for New Zealand in English and Māori, by the National Library Wellington \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Quadrans_Vetus-0.md b/data/en.wikipedia.org/wiki/Quadrans_Vetus-0.md new file mode 100644 index 000000000..ab548aa66 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Quadrans_Vetus-0.md @@ -0,0 +1,21 @@ +--- +title: "Quadrans Vetus" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Quadrans_Vetus" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:46.288636+00:00" +instance: "kb-cron" +--- + +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. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Quadrant_(instrument)-0.md b/data/en.wikipedia.org/wiki/Quadrant_(instrument)-0.md index 117639a39..e58d99a0b 100644 --- a/data/en.wikipedia.org/wiki/Quadrant_(instrument)-0.md +++ b/data/en.wikipedia.org/wiki/Quadrant_(instrument)-0.md @@ -4,7 +4,7 @@ chunk: 1/3 source: "https://en.wikipedia.org/wiki/Quadrant_(instrument)" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:35.683233+00:00" +date_saved: "2026-05-05T09:41:47.522722+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Quadrant_(instrument)-1.md b/data/en.wikipedia.org/wiki/Quadrant_(instrument)-1.md index f138ef773..8e0229c26 100644 --- a/data/en.wikipedia.org/wiki/Quadrant_(instrument)-1.md +++ b/data/en.wikipedia.org/wiki/Quadrant_(instrument)-1.md @@ -4,7 +4,7 @@ chunk: 2/3 source: "https://en.wikipedia.org/wiki/Quadrant_(instrument)" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:35.683233+00:00" +date_saved: "2026-05-05T09:41:47.522722+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Quadrant_(instrument)-2.md b/data/en.wikipedia.org/wiki/Quadrant_(instrument)-2.md index fb49efad1..924b7e8fa 100644 --- a/data/en.wikipedia.org/wiki/Quadrant_(instrument)-2.md +++ b/data/en.wikipedia.org/wiki/Quadrant_(instrument)-2.md @@ -4,7 +4,7 @@ chunk: 3/3 source: "https://en.wikipedia.org/wiki/Quadrant_(instrument)" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:35.683233+00:00" +date_saved: "2026-05-05T09:41:47.522722+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Qubic_experiment-0.md b/data/en.wikipedia.org/wiki/Qubic_experiment-0.md new file mode 100644 index 000000000..519f585fa --- /dev/null +++ b/data/en.wikipedia.org/wiki/Qubic_experiment-0.md @@ -0,0 +1,26 @@ +--- +title: "Qubic experiment" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Qubic_experiment" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:49.439666+00:00" +instance: "kb-cron" +--- + +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 modulates the polarization, followed by a polarizing grid which selects one of the two polarizing angles. The radiation then passes through an array of 400 microwave horns which form multiple beams. The beams are then combined with two convex mirrors to form an interference pattern. The observed beam is the sum of the interferometry fringe patterns. The distance between the peaks of the observed beam is frequency-dependent, so this allows spectral imaging. + + +== Observing site == +Since millimeter waves are absorbed by water vapor in the atmosphere the device must be located at high altitudes above most of the atmosphere. The instrument has been installed at the Large Latin American Millimeter Array (LLAMA) site at Alto de Chorillo near Salta, Argentina, at an altitude of 4,825 meters (15,830 ft). + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Radio_telescope-0.md b/data/en.wikipedia.org/wiki/Radio_telescope-0.md new file mode 100644 index 000000000..002fd6f51 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Radio_telescope-0.md @@ -0,0 +1,39 @@ +--- +title: "Radio telescope" +chunk: 1/3 +source: "https://en.wikipedia.org/wiki/Radio_telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:50.685068+00:00" +instance: "kb-cron" +--- + +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 Laboratories in Holmdel, New Jersey using an antenna built to study radio receiver noise. The first purpose-built radio telescope was a 9-meter parabolic dish constructed by radio amateur Grote Reber in his back yard in Wheaton, Illinois in 1937. The sky survey he performed is often considered the beginning of the field of radio astronomy. + +== Early radio telescopes == + +The first radio antenna used to identify an astronomical radio source was built by Karl Guthe Jansky, an engineer with Bell Telephone Laboratories, in 1932. Jansky was assigned the task of identifying sources of static that might interfere with radiotelephone service. Jansky's antenna was an array of dipoles and reflectors designed to receive short wave radio signals at a frequency of 20.5 MHz (wavelength about 14.6 meters). It was mounted on a turntable that allowed it to rotate in any direction, earning it the name "Jansky's merry-go-round." It had a diameter of approximately 100 ft (30 m) and stood 20 ft (6 m) tall. By rotating the antenna, the direction of the received interfering radio source (static) could be pinpointed. A small shed to the side of the antenna housed an analog pen-and-paper recording system. After recording signals from all directions for several months, Jansky eventually categorized them into three types of static: nearby thunderstorms, distant thunderstorms, and a faint steady hiss above shot noise, of unknown origin. Jansky finally determined that the "faint hiss" repeated on a cycle of 23 hours and 56 minutes. This period is the length of an astronomical sidereal day, the time it takes any "fixed" object located on the celestial sphere to come back to the same location in the sky. Thus Jansky suspected that the hiss originated outside of the Solar System, and by comparing his observations with optical astronomical maps, Jansky concluded that the radiation was coming from the Milky Way Galaxy and was strongest in the direction of the center of the galaxy, in the constellation of Sagittarius. +An amateur radio operator, Grote Reber, was one of the pioneers of what became known as radio astronomy. He built the first parabolic "dish" radio telescope, 9 metres (30 ft) in diameter, in his back yard in Wheaton, Illinois in 1937. He repeated Jansky's pioneering work, identifying the Milky Way as the first off-world radio source, and he went on to conduct the first sky survey at very high radio frequencies, discovering other radio sources. The rapid development of radar during World War II created technology which was applied to radio astronomy after the war, and radio astronomy became a branch of astronomy, with universities and research institutes constructing large radio telescopes. + +== Types == + +The range of frequencies in the electromagnetic spectrum that makes up the radio spectrum is very large. As a consequence, the types of antennas that are used as radio telescopes vary widely in design, size, and configuration. At wavelengths of 30 meters to 3 meters (10–100 MHz), they are generally either directional antenna arrays similar to "TV antennas" or large stationary reflectors with movable focal points. Since the wavelengths being observed with these types of antennas are so long, the "reflector" surfaces can be constructed from coarse wire mesh such as chicken wire. + At shorter wavelengths parabolic "dish" antennas predominate. The angular resolution of a dish antenna is determined by the ratio of the diameter of the dish to the wavelength of the radio waves being observed. This dictates the dish size a radio telescope needs for a useful resolution. Radio telescopes that operate at wavelengths of 3 meters to 30 cm (100 MHz to 1 GHz) are usually well over 100 meters in diameter. Telescopes working at wavelengths shorter than 30 cm (above 1 GHz) range in size from 3 to 90 meters in diameter. + +=== Frequencies === +The increasing use of radio frequencies for communication makes astronomical observations more and more difficult (see Open spectrum). +Negotiations to defend the frequency allocation for parts of the spectrum most useful for observing the universe are coordinated in the Scientific Committee on Frequency Allocations for Radio Astronomy and Space Science. + +Some of the more notable frequency bands used by radio telescopes include: + +Every frequency in the United States National Radio Quiet Zone +Channel 37: 608 to 614 MHz +The "Hydrogen line", also known as the "21 centimeter line": 1,420.40575177 MHz, used by many radio telescopes including The Big Ear in its discovery of the Wow! signal +1,406 MHz and 430 MHz +The Waterhole: 1,420 to 1,666 MHz +The Arecibo Observatory had several receivers that together covered the whole 1–10 GHz range. +The Wilkinson Microwave Anisotropy Probe mapped the cosmic microwave background radiation in 5 different frequency bands, centered on 23 GHz, 33 GHz, 41 GHz, 61 GHz, and 94 GHz. + +=== Big dishes === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Radio_telescope-1.md b/data/en.wikipedia.org/wiki/Radio_telescope-1.md new file mode 100644 index 000000000..4cb135324 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Radio_telescope-1.md @@ -0,0 +1,30 @@ +--- +title: "Radio telescope" +chunk: 2/3 +source: "https://en.wikipedia.org/wiki/Radio_telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:50.685068+00:00" +instance: "kb-cron" +--- + +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 (i.e., transmitting) radar imaging of near-Earth objects (see: radar astronomy); most other telescopes employ passive detection, i.e., receiving only. Arecibo was another stationary dish telescope like FAST. Arecibo's 305 m (1,001 ft) dish was built into a natural depression in the landscape, the antenna was steerable within an angle of about 20° of the zenith by moving the suspended feed antenna, giving use of a 270-meter diameter portion of the dish for any individual observation. +The largest individual radio telescope of any kind is the RATAN-600 located near Nizhny Arkhyz, Russia, which consists of a 576-meter circle of rectangular radio reflectors, each of which can be pointed towards a central conical receiver. +The above stationary dishes are not fully "steerable"; they can only be aimed at points in an area of the sky near the zenith, and cannot receive from sources near the horizon. The largest fully steerable dish radio telescope is the 100 meter Green Bank Telescope in West Virginia, United States, constructed in 2000. The largest fully steerable radio telescope in Europe is the Effelsberg 100-m Radio Telescope near Bonn, Germany, operated by the Max Planck Institute for Radio Astronomy, which also was the world's largest fully steerable telescope for 30 years until the Green Bank antenna was constructed. The third-largest fully steerable radio telescope is the 76-meter Lovell Telescope at Jodrell Bank Observatory in Cheshire, England, completed in 1957. The fourth-largest fully steerable radio telescopes are six 70-meter dishes: three Russian RT-70, and three in the NASA Deep Space Network. The planned Qitai Radio Telescope, at a diameter of 110 m (360 ft), is expected to become the world's largest fully steerable single-dish radio telescope when completed in 2028. +A more typical radio telescope has a single antenna of about 25 meters diameter. Dozens of radio telescopes of about this size are operated in radio observatories all over the world. + +==== Gallery of big dishes ==== + +=== Radio Telescopes in space === + +Since 1965, humans have launched four space-based radio telescopes. The aim of these projects are to take measurements in places with less interference than that on Earth. +The first telescope, KRT-10, was attached to Salyut 6 orbital space station in 1979. +In 1997, Japan sent the second, HALCA. +The third one was sent by Russia in 2011 called Spektr-R. +In 2018, China sent a Dutch radio telescope to the dark side of the Moon. +NASA has plans to build a radio telescope on the dark side of the Moon in the 2030s. + +== Radio interferometry == + +One of the most notable developments came in 1946 with the introduction of the technique called astronomical interferometry, which means combining the signals from multiple antennas so that they simulate a larger antenna, in order to achieve greater resolution. Astronomical radio interferometers usually consist either of arrays of parabolic dishes (e.g., the One-Mile Telescope), arrays of one-dimensional antennas (e.g., the Molonglo Observatory Synthesis Telescope) or two-dimensional arrays of omnidirectional dipoles (e.g., Tony Hewish's Pulsar Array). All of the telescopes in the array are widely separated and are usually connected using coaxial cable, waveguide, optical fiber, or other type of transmission line. Recent advances in the stability of electronic oscillators also now permit interferometry to be carried out by independent recording of the signals at the various antennas, and then later correlating the recordings at some central processing facility. This process is known as Very Long Baseline Interferometry (VLBI). Interferometry does increase the total signal collected, but its primary purpose is to vastly increase the resolution through a process called aperture synthesis. This technique works by superposing (interfering) the signal waves from the different telescopes on the principle that waves that coincide with the same phase will add to each other while two waves that have opposite phases will cancel each other out. This creates a combined telescope that is equivalent in resolution (though not in sensitivity) to a single antenna whose diameter is equal to the spacing of the antennas furthest apart in the array. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Radio_telescope-2.md b/data/en.wikipedia.org/wiki/Radio_telescope-2.md new file mode 100644 index 000000000..40909e1b6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Radio_telescope-2.md @@ -0,0 +1,36 @@ +--- +title: "Radio telescope" +chunk: 3/3 +source: "https://en.wikipedia.org/wiki/Radio_telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:50.685068+00:00" +instance: "kb-cron" +--- + +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 detailed images of the anisotropies and the polarization of the Cosmic Microwave Background, like the CBI interferometer in 2004. +The world's largest physically connected telescope, the Square Kilometre Array (SKA), is planned to start operations in 2027, although the first stations had "first fringes" in 2024. + +== Astronomical observations == + +Many astronomical objects are not only observable in visible light but also emit radiation at radio wavelengths. Besides observing energetic objects such as pulsars and quasars, radio telescopes are able to "image" most astronomical objects such as galaxies, nebulae, and even radio emissions from planets. + +== See also == +Astropulse – distributed computing to search data tapes for primordial black holes, pulsars, and ETI +Ground station +List of astronomical observatories +List of radio telescopes +List of telescope types +Search for extraterrestrial intelligence +Telescope +Radar telescope + +== References == + +== Further reading == + +Rohlfs, K., & Wilson, T. L. (2004). Tools of radio astronomy. Astronomy and astrophysics library. Berlin, Germany: Springer. +Asimov, I. (1979). Isaac Asimov's Book of facts; Sky Watchers. New York: Grosset & Dunlap. pp. 390–399. ISBN 0-8038-9347-7. + +== External links == +PICTOR: A free-to-use radio telescope \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Rapid_Eye_Mount_telescope-0.md b/data/en.wikipedia.org/wiki/Rapid_Eye_Mount_telescope-0.md new file mode 100644 index 000000000..590623a34 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Rapid_Eye_Mount_telescope-0.md @@ -0,0 +1,40 @@ +--- +title: "Rapid Eye Mount telescope" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Rapid_Eye_Mount_telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:51.860272+00:00" +instance: "kb-cron" +--- + +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 is optimized for the observation of scheduled targets but it is immediately overdriven by GRB (or other) alerts. Typically REM can observe the new target after 30 seconds from notification. +REM has been installed in its place during June 2003 and has been gathering data on GRB and other sources since then. Also it is a bench for experimental instrumentation and equipment. +In 2006 a wide-field camera parallel to the REM telescope, the TORTORA camera (Telescopio Ottimizzato per la Ricerca dei Transienti Ottici RApidi) was installed. TORTORA has a field of view of 24°x32° through an objective of 120 mm diameter. The instrument was optimized for photometry of fast transients with a best time resolution of about 0.1 s. In 2014 TORTORA was definitely decommissioned and removed from REM. +The observatory is operated for the Instituto Nazionale di Astrofisica by the REM Team. and observing time is offered to the world-wide community on a open sky policy. + + +== Main results == +Since its installation and commissioning at ESO, REM rapid and multi-band observations allowed to contribute to several important discoveries in some cases widely reported by ESO press releases; for instance, the observations a few seconds after its discovery of GRB060418, GRB06067A and GRB080319B. +In addition, a larger set of observations of targets different from GRBs has been performed, securing long time series of data for variable stars, AGNs, etc. + + +== References == + + +== External links == +INAF REM site +ESO press release about GRB060418 and GRB060607A +ESO press release about GRB080319B +REM and TORTORA + + +== See also == +TAROT-South robotic observatory, an even smaller and faster-moving telescope also at La Silla \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Rectangulus-0.md b/data/en.wikipedia.org/wiki/Rectangulus-0.md index e99db8807..81c78afa1 100644 --- a/data/en.wikipedia.org/wiki/Rectangulus-0.md +++ b/data/en.wikipedia.org/wiki/Rectangulus-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Rectangulus" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:39.220993+00:00" +date_saved: "2026-05-05T09:41:53.068211+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Reflecting_instrument-0.md b/data/en.wikipedia.org/wiki/Reflecting_instrument-0.md new file mode 100644 index 000000000..2e8bb5604 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Reflecting_instrument-0.md @@ -0,0 +1,30 @@ +--- +title: "Reflecting instrument" +chunk: 1/4 +source: "https://en.wikipedia.org/wiki/Reflecting_instrument" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:54.244254+00:00" +instance: "kb-cron" +--- + +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 permit two objects to be observed in a single view. What followed is a series of inventions and improvements that refined the instrument to the point that its accuracy exceeded that which was required for determining longitude. Any further improvements required a completely new technology. + +== Early reflecting instruments == +Some of the early reflecting instruments were proposed by scientists such as Robert Hooke and Isaac Newton. These were little used or may not have been built or tested extensively. The van Breen instrument was the exception, in that it was used by the Dutch. However, it had little influence outside of the Netherlands. + +=== Joost van Breen's reflecting cross-staff === +Invented in 1660 by the Dutch Joost van Breen, the spiegelboog (mirror-bow) was a reflecting cross staff. This instrument appears to have been used for approximately 100 years, mainly in the Zeeland Chamber of the VOC (The Dutch East India Company). + +=== Robert Hooke's single-reflecting instrument === + +Hooke's instrument was a single-reflecting instrument. It used a single mirror to reflect the image of an astronomical object to the observer's eye. This instrument was first described in 1666 and a working model was presented by Hooke at a meeting of the Royal Society some time later. +The device consisted of three primary components, an index arm, a radial arm and a graduated chord. The three were arranged in a triangle as in the image on the right. A telescopic sight was mounted on the index arm. At the point of rotation of the radial arm, a single mirror was mounted. This point of rotation allowed the angle between the index arm and the radial arm to be changed. The graduated chord was connected to the opposite end of the radial arm and the chord was permitted to rotate about the end. The chord was held against the distant end of the index arm and slid against it. The graduations on the chord were uniform and, by using it to measure the distance between the ends of the index arm and the radial arm, the angle between those arms could be determined. A table of chords was used to convert a measurement of distance to a measurement of angle. The use of the mirror resulted in the measured angle being twice the angle included by the index and the radius arm. +The mirror on the radial arm was small enough that the observer could see the reflection of an object in half the telescope's view while seeing straight ahead in the other half. This allowed the observer to see both objects at once. Aligning the two objects together in the telescopes view resulted in the angular distance between them to be represented on the graduated chord. +While Hooke's instrument was novel and attracted some attention at the time, there is no evidence that it was subjected to any tests at sea. The instrument was little used and did not have any significant effect on astronomy or navigation. + +=== Halley's reflecting instrument === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Reflecting_instrument-1.md b/data/en.wikipedia.org/wiki/Reflecting_instrument-1.md new file mode 100644 index 000000000..2d8c5346b --- /dev/null +++ b/data/en.wikipedia.org/wiki/Reflecting_instrument-1.md @@ -0,0 +1,33 @@ +--- +title: "Reflecting instrument" +chunk: 2/4 +source: "https://en.wikipedia.org/wiki/Reflecting_instrument" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:54.244254+00:00" +instance: "kb-cron" +--- + +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 to facilitate this and allow for fine adjustment of the angle, a screw (EC) is mounted so as to allow the observer to change the distance between the two vertexes (E and C). +The observer sights the horizon with the direct lens' view and sights a celestial object in the mirror. Turning the screw to bring the two images directly adjacent sets the instrument. The angle is determined by taking the length of the screw between E and C and converting this to an angle in a table of chords. +Halley specified that the telescope tube be rectangular in cross section. This makes construction easy, but is not a requirement as other cross section shapes can be accommodated. The four sides of the radio latino portion (CD, DE, EF, FC) must be equal in length in order for the angle between the telescope and the objective lens side (ADC) to be precisely twice the angle between the telescope and the mirror (ADF) (or in other words – to enforce the angle of incidence being equal to the angle of reflection). Otherwise, instrument collimation will be compromised and the resulting measurements would be in error. +The celestial object's elevation angle could have been determined by reading from graduations on the staff at the slider, however, that's not how Halley designed the instrument. This may suggest that the overall design of the instrument was coincidentally like a radio latino and that Halley may not have been familiar with that instrument. +There is no knowledge of whether this instrument was ever tested at sea. + +=== Newton's reflecting quadrant === + +Newton's reflecting quadrant was similar in many respects to Hadley's first reflecting quadrant that followed it. +Newton had communicated the design to Edmund Halley around 1699. However, Halley did not do anything with the document and it remained in his papers only to be discovered after his death. However, Halley did discuss Newton's design with members of the Royal Society when Hadley presented his reflecting quadrant in 1731. Halley noted that Hadley's design was quite similar to the earlier Newtonian instrument. +As a result of this inadvertent secrecy, Newton's invention played little role in the development of reflecting instruments. + +== The octant == + +What is remarkable about the octant is the number of persons who independently invented the device in a short period of time. John Hadley and Thomas Godfrey both get credit for inventing the octant. They independently developed the same instrument around 1731. They were not the only ones, however. +In Hadley's case, two instruments were designed. The first was an instrument very similar to Newton's reflecting quadrant. The second had essentially the same form as the modern sextant. Few of the first design were constructed, while the second became the standard instrument from which the sextant derived and, along with the sextant, displaced all prior navigation instruments used for celestial navigation. +Caleb Smith, an English insurance broker with a strong interest in astronomy, had created an octant in 1734. He called it an Astroscope or Sea-Quadrant. He used a fixed prism in addition to an index mirror to provide reflective elements. Prisms provide advantages over mirrors in an era when polished speculum metal mirrors were inferior and both the silvering of a mirror and the production of glass with flat, parallel surfaces was difficult. However, the other design elements of Smith's instrument made it inferior to Hadley's octant and it was not used significantly. +Jean-Paul Fouchy, a mathematics professor and astronomer in France, invented an octant in 1732. His was essentially the same as Hadley's. Fouchy did not know of the developments in England at the time, since communications between the two country's instrument makers was limited and the publications of the Royal Society, particularly the Philosophical Transactions, were not being distributed in France. Fouchy's octant was overshadowed by Hadley's. + +== The sextant == +The main article, Sextant, covers the use of the instrument in navigation. This article concentrates on the history and the development of the instrument \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Reflecting_instrument-2.md b/data/en.wikipedia.org/wiki/Reflecting_instrument-2.md new file mode 100644 index 000000000..e615ac891 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Reflecting_instrument-2.md @@ -0,0 +1,43 @@ +--- +title: "Reflecting instrument" +chunk: 3/4 +source: "https://en.wikipedia.org/wiki/Reflecting_instrument" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:54.244254+00:00" +instance: "kb-cron" +--- + +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 were about a centimetre apart. This significantly increased the stiffness of the frame. An earlier version had a second frame that only covered the upper part of the instrument, securing the mirrors and telescope. Later versions used two full frames. Since the spacers looked like little pillars, these were also called pillar sextants. +Troughton also experimented with alternative materials. The scales were plated with silver, gold or platinum. Gold and platinum both minimized corrosion problems. The platinum-plated instruments were expensive, due to the scarcity of the metal, though less expensive than gold. Troughton knew William Hyde Wollaston through the Royal Society and this gave him access to the precious metal. Instruments from Troughton's company that used platinum can be easily identified by the word Platina engraved on the frame. These instruments remain highly valued as collector's items and are as accurate today as when they were constructed. +As the developments in dividing engines progressed, the sextant was more accurate and could be made smaller. In order to permit easy reading of the vernier, a small magnifying lens was added. In addition, to reduce glare on the frame, some had a diffuser surrounding the magnifier to soften the light. As accuracy increased, the circular arc vernier was replaced with a drum vernier. +Frame designs were modified over time to create a frame that would not be adversely affected by temperature changes. These frame patterns became standardized and one can see the same general shape in many instruments from many different manufacturers. +In order to control costs, modern sextants are now available in precision-made plastic. These are light, affordable and of high quality. + +== Types of sextants == +While most people think of navigation when they hear the term sextant, the instrument has been used in other professions. + +Navigator's sextant +The common type of instrument most people think of when they hear the term sextant. +Sounding sextants +These are sextants that were constructed for use horizontally rather than vertically and were developed for use in hydrographic surveys. +Surveyor's sextants +These were constructed for use exclusively on land for horizontal angular measurements. Instead of a handle on the frame, they had a socket to allow the attachment of a surveyor's Jacob's staff. +Box or pocket sextants +These are small sextants entirely contained within a metal case. First developed by Edward Troughton, they are usually all brass with most of the mechanical components inside the case. The telescope extends from an opening in the side. The index and other parts are completely covered when the case cover is slipped on. Popular with surveyors for their small size (typically only 6.5–8 cm [2+1⁄2–3+1⁄4 in] in diameter and 5 cm [2 in] deep), their accuracy was enabled by improvements in the dividing engines used to graduate the arcs. The arcs are so small that magnifiers are attached to allow them to be read. +In addition to these types, there are terms used for various sextants. +A pillar sextant can be either: + +A double-frame sextant as patented by Edward Troughton in 1788. +A surveyor's sextant with a socket for a surveyor's staff (the pillar). +The former is the most common use of the term. + +== Beyond the sextant == + +=== Quintant and others === +Several makers offered instruments with sizes other than one-eighth or one-sixth of a circle. One of the most common was the quintant or fifth of a circle (72° arc reading to 144°). Other sizes were also available, but the odd sizes never became common. Many instruments are found with scales reading to, for example, 135°, but they are simply referred to as sextants. Similarly, there are 100° octants, but these are not separated as unique types of instruments. +There was interest in much larger instruments for special purposes. In particular a number of full circle instruments were made, categorized as reflecting circles and repeating circles. + +=== Reflecting circles === \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Reflecting_instrument-3.md b/data/en.wikipedia.org/wiki/Reflecting_instrument-3.md new file mode 100644 index 000000000..ae4734828 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Reflecting_instrument-3.md @@ -0,0 +1,29 @@ +--- +title: "Reflecting instrument" +chunk: 4/4 +source: "https://en.wikipedia.org/wiki/Reflecting_instrument" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:54.244254+00:00" +instance: "kb-cron" +--- + +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 be used to receive an image from either side relative to the telescope. This eliminated the need to ascertain that the mirrors were precisely parallel when reading zero. This simplified the use of the instrument. Further refinements were performed with the help of Etienne Lenoir. The two of them refined the instrument to its definitive form in 1777. This instrument was so distinctive it was given the name Borda circle or repeating circle. +Borda and Lenoir developed the instrument for geodetic surveying. Since it was not used for the celestial measures, it did not use double reflection and substituted two telescope sights. As such, it was not a reflecting instrument. It was notable as being the equal of the great theodolite created by the renowned instrument maker, Jesse Ramsden. +Josef de Mendoza y Ríos redesigned Borda's reflecting circle (London, 1801). The goal was to use it together with his Lunar Tables published by the Royal Society (London, 1805). He made a design with two concentric circles and a vernier scale and recommended averaging three sequential readings to reduce the error. Borda's system was not based on a circle of 360° but 400 grads (Borda spent years calculating his tables with a circle divided in 400°). Mendoza's lunar tables have been used through almost the entire nineteenth century (see Lunar distance (navigation)). +Edward Troughton also modified the reflecting circle. He created a design with three index arms and verniers. This permitted three simultaneous readings to average out the error. +As a navigation instrument, the reflecting circle was more popular with the French navy than with the British. + +=== Bris sextant === + +The Bris sextant is not a true sextant, but it is a true reflecting instrument based on the principle of double reflection and subject to the same rules and errors as common octants and sextants. Unlike common octants and sextants, the Bris sextant is a fixed angle instrument capable of accurately measuring a few specific angles unlike other reflecting instruments which can measure any angle within the range of the instrument. It is particularly suited to determining the altitude of the sun or moon. + +=== Surveying sector === +Francis Ronalds invented an instrument for recording angles in 1829 by modifying the octant. A disadvantage of reflecting instruments in surveying applications is that optics dictate that the mirror and index arm rotate through half the angular separation of the two objects. The angle thus needs to be read, noted and a protractor employed to draw the angle on a plan. Ronalds' idea was to configure the index arm to rotate through twice the angle of the mirror, so that the arm could then be used to draw a line at the correct angle directly onto the drawing. He used a sector as the basis of his instrument and placed the horizon glass at one tip and the index mirror near the hinge connecting the two rulers. The two revolving elements were linked mechanically and the barrel supporting the mirror was twice the diameter of the hinge to give the required angular ratio. + +== References == + +== External links == +National Maritime Museum Portrait of a merchant navy captain holding a Caleb Smith Octant. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Reticle-0.md b/data/en.wikipedia.org/wiki/Reticle-0.md new file mode 100644 index 000000000..e84fb286c --- /dev/null +++ b/data/en.wikipedia.org/wiki/Reticle-0.md @@ -0,0 +1,35 @@ +--- +title: "Reticle" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Reticle" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:55.447970+00:00" +instance: "kb-cron" +--- + +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 and surveying, and are also popular in graphical user interfaces as a precision pointer. The reticle is said to have been invented by Robert Hooke, and dates to the 17th century. Another candidate as inventor is the amateur astronomer William Gascoigne, who predated Hooke. +The term reticle comes from the Latin reticulum, meaning small net. + +== Uses == + +=== Firearms === +Telescopic sights for firearms, generally just called scopes, are probably the device most often associated with crosshairs. Motion pictures and the media often use a view through crosshairs as a dramatic device, which has given crosshairs wide cultural exposure. + +==== Reticle shape ==== +While the traditional thin crossing lines are the original and still the most familiar cross-hair shape, they are really best suited for precision aiming at high contrast targets, as the thin lines are easily lost in complex backgrounds, such as those encountered while hunting. Thicker bars are much easier to discern against a complex background, but lack the precision of thin bars. The most popular types of cross-hair in modern scopes are variants on the duplex cross-hair, with bars that are thick on the perimeter and thin out in the middle. The thick bars allow the eye to quickly locate the center of the reticle, and the thin lines in the center allow for precision aiming. The thin bars in a duplex reticle may also be designed to be used as a measure. Called a 30/30 reticle, the thin bars on such a reticle span 30 minutes of arc (0.5º), which is approximately equal to 30 inches at 100 yards or 90 centimeters at 100 meters. This enables an experienced shooter to deduce, on the basis of the known size of an object in view, (as opposed to guess or estimate) the range within an acceptable error limit. + +==== Wire crosshairs ==== + +Originally crosshairs were constructed out of hair or spiderweb, these materials being sufficiently thin and strong. Many modern scopes use wire crosshairs, which can be flattened to various degrees to change the width. These wires are usually silver in color, but appear black when backlit by the image passing through the scope's optics. Wire reticles are by nature fairly simple, as they require lines that pass all the way across the reticle, and the shapes are limited to the variations in thickness allowed by flattening the wire; duplex crosshairs, and crosshairs with dots are possible, and multiple horizontal or vertical lines may be used. The advantage of wire crosshairs is that they are fairly tough and durable, and provide no obstruction to light passing through the scope. + +==== Etched reticles ==== + +The first suggestion for etched glass reticles was made by Philippe de La Hire in 1700. His method was based on engraving the lines on a glass plate with a diamond point. Many modern crosshairs are actually etched onto a thin plate of glass, which allows a far greater latitude in shapes. Etched glass reticles can have floating elements, which do not cross the reticle; circles and dots are common, and some types of glass reticles have complex sections designed for use in range estimation and bullet drop and drift compensation (see external ballistics). A potential disadvantage of glass reticles is that the surface of the glass reflects some light (about 4% per surface on uncoated glass) lessening transmission through the scope, although this light loss is near zero if the glass is multicoated (coating being the norm for all modern high quality optical products). + +==== Illuminated reticles ==== +Reticles may be illuminated, either by a plastic or fiber optic light pipe collecting ambient light or, in low light conditions, by a battery powered LED. Some sights also use the radioactive decay of tritium for illumination that can work for 11 years without using a battery, used in the British SUSAT sight for the SA80 (L85) assault rifle and in the American ACOG (Advanced Combat Optical Gunsight). Red is the most common color used, as it is the least destructive to the shooter's night vision, but some products use green or yellow illumination, either as a single colour or changeable via user selection. + +==== Graticule ==== +Another term for reticle is graticule, which is frequently encountered in British and British military technical manuals. It came into common use during World War I. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Reticle-1.md b/data/en.wikipedia.org/wiki/Reticle-1.md new file mode 100644 index 000000000..3f152f927 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Reticle-1.md @@ -0,0 +1,48 @@ +--- +title: "Reticle" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Reticle" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:55.447970+00:00" +instance: "kb-cron" +--- + +=== 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. These types of sights are used on surveying/triangulating equipment, to aid celestial telescope aiming, and as sights on firearms. Historically they were used on larger military weapon systems that could supply an electrical source to illuminate them and where the operator needed a wide field of view to track and range a moving target visually (i.e. weapons from the pre laser/radar/computer era). More recently sights using low power consumption durable light emitting diodes as the reticle (called red dot sights) have become common on small arms with versions like the Aimpoint CompM2 being widely fielded by the U.S. Military. + +==== Holographic reticles ==== +Holographic weapon sights use a holographic image of a reticle at finite set range built into the viewing window and a collimated laser diode to illuminate it. An advantage to holographic sights is that they eliminate a type of parallax problem found in some optical collimator based sights (such as the red dot sight) where the spherical mirror used induces spherical aberration that can cause the reticle to skew off the sight's optical axis. The use of a hologram also eliminates the need for image dimming narrow band reflective coatings and allows for reticles of almost any shape or mil size. A downside to the holographic weapon sight can be the weight and shorter battery life. As with red dot sights, holographic weapon sights have also become common on small arms with versions like the Eotech 512.A65 and similar models fielded by the U.S. Military and various law enforcement agencies. + +=== Surveying and astronomy === +In older instruments, reticle crosshairs and stadia marks were made using threads taken from the cocoon of the brown recluse spider. This very fine, strong spider silk makes for an excellent crosshair. + +==== Surveying ==== +In surveying, reticles are designed for specific uses. Levels and theodolites would have slightly different reticles. However, both may have features such as stadia marks to allow distance measurements. + +==== Astronomy ==== +For astronomical uses, reticles could be simple crosshair designs or more elaborate designs for special purposes. Telescopes used for polar alignment could have a reticle that indicates the position of Polaris relative to the north celestial pole. Telescopes that are used for very precise measurements would have a filar micrometer as a reticle; this could be adjusted by the operator to measure angular distances between stars. +For aiming telescopes, reflex sights are popular, often in conjunction with a small telescope with a crosshair reticle. They make aiming the telescope at an astronomical object easier. +The constellation Reticulum was designated to recognize the reticle and its contributions to astronomy. + +== See also == +Adrien Auzout +Deflection (ballistics) +Focusing screen – used in photography, and often etched +Iron sight +List of astronomical instruments +Ocular micrometer +Photomask – partial plate with holes or transparencies used in photolithography integrated circuit fabrication is also called a "reticle" +Sniper +Target blip +Parallax + +== References == + +== External links == + +Reticles \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Rotational_modulation_collimator-0.md b/data/en.wikipedia.org/wiki/Rotational_modulation_collimator-0.md new file mode 100644 index 000000000..d43b99db7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Rotational_modulation_collimator-0.md @@ -0,0 +1,23 @@ +--- +title: "Rotational modulation collimator" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Rotational_modulation_collimator" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:56.618148+00:00" +instance: "kb-cron" +--- + +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 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SOPHIE_échelle_spectrograph-0.md b/data/en.wikipedia.org/wiki/SOPHIE_échelle_spectrograph-0.md new file mode 100644 index 000000000..fd6a886ba --- /dev/null +++ b/data/en.wikipedia.org/wiki/SOPHIE_échelle_spectrograph-0.md @@ -0,0 +1,36 @@ +--- +title: "SOPHIE échelle spectrograph" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SOPHIE_échelle_spectrograph" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:07.213775+00:00" +instance: "kb-cron" +--- + +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 set to R = 40000. +The R2 échelle diffraction grating has 52.65 grooves per millimeter and was manufactured by Richardson Gratings. It is blazed at 65° and its size is 20.4 cm x 40.8 cm. It is mounted in a fixed configuration. The spectrum is projected onto the E2V Technologies type 44-82 CCD detector of 4096 x 2048 pixels kept at a constant temperature of –100 °C. This grating yields 41 spectral orders, of which 39 are currently extracted, to obtain wavelengths between 387.2 nm and 694.3 nm. + + +== Performance == + +In HE mode, a signal-to-noise ratio (per pixel) of 27 was reached in 90 min for an object of magnitude 14.5 in the V band. +The stability of the instrument can be described by the lowest dispersion possible for radial velocity observations, in m/s. In HR mode the short term stability has been measured to be 1.3 m/s, while it is 2 m/s for longer timescales. + + +== See also == +CORALIE spectrograph +HARPS spectrograph + + +== References == + + +== External links == +SOPHIE Home Page \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SPEX_(astronomy)-0.md b/data/en.wikipedia.org/wiki/SPEX_(astronomy)-0.md new file mode 100644 index 000000000..e4509a4e7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SPEX_(astronomy)-0.md @@ -0,0 +1,26 @@ +--- +title: "SPEX (astronomy)" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SPEX_(astronomy)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:10.747902+00:00" +instance: "kb-cron" +--- + +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, Daphne M.; Keller, Christoph U.; Laan, Erik C.; Verlaan, Ad L.; Vliegenthart, Willem A.; ter Horst, Rik; Navarro, Ramón; Wielinga, Klaas; Hannemann, Sandro; Moon, Scott G.; Voors, Robert (2011). Shaw, Joseph A.; Tyo, J. Scott (eds.). Prototyping for the Spectropolarimeter for Planetary EXploration (SPEX): calibration and sky measurements (PDF). Proceedings of the SPIE: Polarization Science and Remote Sensing V (Sunday 21 August 2011 San Diego, California, USA). Vol. 8160. pp. 81600Z. doi:10.1117/12.893741. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Santucci's_Armillary_Sphere-0.md b/data/en.wikipedia.org/wiki/Santucci's_Armillary_Sphere-0.md new file mode 100644 index 000000000..11917b214 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Santucci's_Armillary_Sphere-0.md @@ -0,0 +1,21 @@ +--- +title: "Santucci's Armillary Sphere" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Santucci's_Armillary_Sphere" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:41:57.791668+00:00" +instance: "kb-cron" +--- + +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. La sfera armillare di Tolomeo. Tipografia del Vocabolario, 1876. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sextant-0.md b/data/en.wikipedia.org/wiki/Sextant-0.md new file mode 100644 index 000000000..f797d3b65 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Sextant-0.md @@ -0,0 +1,23 @@ +--- +title: "Sextant" +chunk: 1/4 +source: "https://en.wikipedia.org/wiki/Sextant" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:00.116585+00:00" +instance: "kb-cron" +--- + +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, it was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho. + +== Navigational sextants == +Like the Davis quadrant, the sextant allows celestial objects to be measured relative to the horizon, rather than relative to the instrument. This allows excellent precision. Also, unlike the backstaff, the sextant allows direct observations of stars. This permits the use of the sextant at night when a backstaff is difficult to use. For solar observations, filters allow direct observation of the Sun. +Since the measurement is relative to the horizon, the measuring pointer is a beam of light that reaches to the horizon. The measurement is thus limited by the angular accuracy of the instrument and not the sine error of the length of an alidade, as it is in a mariner's astrolabe or similar older instrument. +A sextant does not require a completely steady aim, because it measures a relative angle. For example, when a sextant is used on a moving ship, the image of both horizon and celestial object will move around in the field of view. However, the relative position of the two images will remain steady, and as long as the user can determine when the celestial object touches the horizon, the accuracy of the measurement will remain high compared to the magnitude of the movement. +The sextant is not dependent upon electricity (unlike many forms of modern navigation) or any human-controlled signals (such as GPS). For these reasons it is considered to be an eminently practical back-up navigation tool for ships. + +== Design == +The frame of a sextant is in the shape of a sector which is approximately 1⁄6 of a circle (60°), hence its name (sextāns, sextantis is the Latin word for "one sixth"). Both smaller and larger instruments are (or were) in use: the octant, quintant (or pentant) and the (doubly reflecting) quadrant span sectors of approximately 1⁄8 of a circle (45°), 1⁄5 of a circle (72°) and 1⁄4 of a circle (90°), respectively. All of these instruments may be termed "sextants". \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sextant-1.md b/data/en.wikipedia.org/wiki/Sextant-1.md new file mode 100644 index 000000000..5ab6520fd --- /dev/null +++ b/data/en.wikipedia.org/wiki/Sextant-1.md @@ -0,0 +1,22 @@ +--- +title: "Sextant" +chunk: 2/4 +source: "https://en.wikipedia.org/wiki/Sextant" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:00.116585+00:00" +instance: "kb-cron" +--- + +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 between the fixed ray and the object ray must therefore increase by 40°. This is the case shown in the graphic. +There are two types of horizon mirrors on the market today. Both types give good results. +Traditional sextants have a half-horizon mirror, which divides the field of view in two. On one side, there is a view of the horizon; on the other side, a view of the celestial object. The advantage of this type is that both the horizon and celestial object are bright and as clear as possible. This is superior at night and in haze, when the horizon and/or a star being sighted can be difficult to see. However, one has to sweep the celestial object to ensure that the lowest limb of the celestial object touches the horizon. +Whole-horizon sextants use a half-silvered horizon mirror to provide a full view of the horizon. This makes it easy to see when the bottom limb of a celestial object touches the horizon. Since most sights are of the Sun or Moon, and haze is rare without overcast, the low-light advantages of the half-horizon mirror are rarely important in practice. +In both types, larger mirrors give a larger field of view, and thus make it easier to find a celestial object. Modern sextants often have 5 cm or larger mirrors, while 19th-century sextants rarely had a mirror larger than 2.5 cm (one inch). In large part, this is because precision flat mirrors have grown less expensive to manufacture and to silver. +An artificial horizon is useful when the horizon is invisible, as occurs in fog, on moonless nights, in a calm, when sighting through a window or on land surrounded by trees or buildings. There are two common designs of artificial horizon. An artificial horizon can consist simply of a pool of water shielded from the wind, allowing the user to measure the distance between the body and its reflection, and divide by two. Another design allows the mounting of a fluid-filled tube with bubble directly to the sextant. +Most sextants also have filters for use when viewing the Sun and reducing the effects of haze. The filters usually consist of a series of progressively darker glasses that can be used singly or in combination to reduce haze and the Sun's brightness. However, sextants with adjustable polarizing filters have also been manufactured, where the degree of darkness is adjusted by twisting the frame of the filter. +Most sextants mount a 1 or 3-power monocular for viewing. Many users prefer a simple sighting tube, which has a wider, brighter field of view and is easier to use at night. Some navigators mount a light-amplifying monocular to help see the horizon on moonless nights. Others prefer to use a lit artificial horizon. +Professional sextants use a click-stop degree measure and a worm adjustment that reads to a minute, 1/60 of a degree. Most sextants also include a vernier on the worm dial that reads to 0.1 minute. Since 1 minute of error is about a nautical mile, the best possible accuracy of celestial navigation is about 0.1 nautical miles (190 m). At sea, results within several nautical miles, well within visual range, are acceptable. A highly skilled and experienced navigator can determine position to an accuracy of about 0.25-nautical-mile (460 m). +A change in temperature can warp the arc, creating inaccuracies. Many navigators purchase weatherproof cases so that their sextant can be placed outside the cabin to come to equilibrium with outside temperatures. The standard frame designs (see illustration) are supposed to equalise differential angular error from temperature changes. The handle is separated from the arc and frame so that body heat does not warp the frame. Sextants for tropical use are often painted white to reflect sunlight and remain relatively cool. High-precision sextants have an invar (a special low-expansion steel) frame and arc. Some scientific sextants have been constructed of quartz or ceramics with even lower expansions. Many commercial sextants use low-expansion brass or aluminium. Brass is lower-expansion than aluminium, but aluminium sextants are lighter and less tiring to use. Some say they are more accurate because one's hand trembles less. Solid brass frame sextants are less susceptible to wobbling in high winds or when the vessel is working in heavy seas, but as noted are substantially heavier. Sextants with aluminum frames and brass arcs have also been manufactured. Essentially, a sextant is intensely personal to each navigator, and they will choose whichever model has the features which suit them best. +Aircraft sextants are now out of production, but had special features. Most had artificial horizons to permit taking a sight through a flush overhead window. Some also had mechanical averagers to make hundreds of measurements per sight for compensation of random accelerations in the artificial horizon's fluid. Older aircraft sextants had two visual paths, one standard and the other designed for use in open-cockpit aircraft that let one view from directly over the sextant in one's lap. More modern aircraft sextants were periscopic with only a small projection above the fuselage. With these, the navigator pre-computed their sight and then noted the difference in observed versus predicted height of the body to determine their position. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sextant-2.md b/data/en.wikipedia.org/wiki/Sextant-2.md new file mode 100644 index 000000000..f2ce0f24d --- /dev/null +++ b/data/en.wikipedia.org/wiki/Sextant-2.md @@ -0,0 +1,21 @@ +--- +title: "Sextant" +chunk: 3/4 +source: "https://en.wikipedia.org/wiki/Sextant" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:00.116585+00:00" +instance: "kb-cron" +--- + +== 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 moving it towards higher values of the scale, eventually the image of the Sun will reappear on the index mirror and can be aligned to about the level of the horizon on the horizon mirror. Then the fine adjustment screw on the end of the index bar is turned until the bottom curve (the lower limb) of the Sun just touches the horizon. "Swinging" the sextant about the axis of the telescope ensures that the reading is being taken with the instrument held vertically. The angle of the sight is then read from the scale on the arc, making use of the micrometer or vernier scale provided. The exact time of the sight must also be noted simultaneously, and the height of the eye above sea-level recorded. +An alternative method is to estimate the current altitude (angle) of the Sun from navigation tables, then set the index bar to that angle on the arc, apply suitable shades only to the index mirror, and point the instrument directly at the horizon, sweeping it from side to side until a flash of the Sun's rays are seen in the telescope. Fine adjustments are then made as above. This method is less likely to be successful for sighting stars and planets. +Star and planet sights are normally taken during nautical twilight at dawn or dusk, while both the heavenly bodies and the sea horizon are visible. There is no need to use shades or to distinguish the lower limb as the body appears as a mere point in the telescope. The Moon can be sighted, but it appears to move very fast, appears to have different sizes at different times, and sometimes only the lower or upper limb can be distinguished due to its phase. +After a sight is taken, it is reduced to a position by looking at several mathematical procedures. The simplest sight reduction is to draw the equal-altitude circle of the sighted celestial object on a globe. The intersection of that circle with a dead-reckoning track, or another sighting, gives a more precise location. +Sextants can be used very accurately to measure other visible angles, for example between one heavenly body and another and between landmarks ashore. Used horizontally, a sextant can measure the apparent angle between two landmarks such as a lighthouse and a church spire, which can then be used to find the distance off or out to sea (provided the distance between the two landmarks is known). Used vertically, a measurement of the angle between the lantern of a lighthouse of known height and the sea level at its base can also be used for distance off. + +== Adjustment == +Due to the sensitivity of the instrument it is easy to knock the mirrors out of adjustment. For this reason a sextant should be checked frequently for errors and adjusted accordingly. +There are four errors that can be adjusted by the navigator, and they should be removed in the following order. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sextant-3.md b/data/en.wikipedia.org/wiki/Sextant-3.md new file mode 100644 index 000000000..04a6f4e2f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Sextant-3.md @@ -0,0 +1,34 @@ +--- +title: "Sextant" +chunk: 4/4 +source: "https://en.wikipedia.org/wiki/Sextant" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:00.116585+00:00" +instance: "kb-cron" +--- + +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 there are two horizons there is side error. In both cases, adjust the horizon glass/mirror until respectively the star or the horizon dual images merge into one. Side error is generally inconsequential for observations and can be ignored or reduced to a level that is merely inconvenient. +Collimation error +This is when the telescope or monocular is not parallel to the plane of the sextant. To check for this you need to observe two stars 90° or more apart. Bring the two stars into coincidence either to the left or the right of the field of view. Move the sextant slightly so that the stars move to the other side of the field of view. If they separate there is collimation error. As modern sextants rarely use adjustable telescopes, they do not need to be corrected for collimation error. +Index error +This occurs when the index and horizon mirrors are not parallel to each other when the index arm is set to zero. To test for index error, zero the index arm and observe the horizon. If the reflected and direct image of the horizon are in line there is no index error. If one is above the other adjust the index mirror until the two horizons merge. Alternatively, the same procedure can be done at night using a star or the Moon instead of the horizon. + +== See also == + +== Notes == + +== References == + +== External links == + +Her Majesty's Nautical Almanac Office Archived 2011-02-21 at the Wayback Machine +The History of HM Nautical Almanac Office Archived 2016-06-24 at the Wayback Machine +Chapter 17 from the online edition of Nathaniel Bowditch's American Practical Navigator +Understand difference in Antique & Replica Sextant Archived 2017-08-17 at the Wayback Machine +CD-Sextant - Build your own sextant Simple do-it-yourself project. +Lunars web site. online calculation +Complete celnav theory book, including Lunars \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sextant_(astronomy)-0.md b/data/en.wikipedia.org/wiki/Sextant_(astronomy)-0.md index f4d92cebd..2d7ff96f4 100644 --- a/data/en.wikipedia.org/wiki/Sextant_(astronomy)-0.md +++ b/data/en.wikipedia.org/wiki/Sextant_(astronomy)-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Sextant_(astronomy)" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:42.520007+00:00" +date_saved: "2026-05-05T09:42:01.323619+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Shadow_square-0.md b/data/en.wikipedia.org/wiki/Shadow_square-0.md index 2eb2d0d50..448fd3887 100644 --- a/data/en.wikipedia.org/wiki/Shadow_square-0.md +++ b/data/en.wikipedia.org/wiki/Shadow_square-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Shadow_square" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:37:43.709972+00:00" +date_saved: "2026-05-05T09:42:02.531171+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Sine_quadrant-0.md b/data/en.wikipedia.org/wiki/Sine_quadrant-0.md new file mode 100644 index 000000000..9b5db79b6 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Sine_quadrant-0.md @@ -0,0 +1,40 @@ +--- +title: "Sine quadrant" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Sine_quadrant" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:03.664274+00:00" +instance: "kb-cron" +--- + +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 of the arc. That is, one set of numbers begins at the left end of the arc and counts up to 90 at the right end, while the other starts on the right and the 90 is at the left. This double numbering enables the instrument to measure either celestial altitude or zenith distance or both simultaneously. +At the apex—where the two graduated straight sides of the grid pattern meet in a right angle—is a thin cord strung through a pin hole and weighted with a small bead. The cord is called a khait and is used as a plumb line when measuring celestial altitudes. It is also used to indicate angles when doing calculations with the instrument; the sliding bead facilitates trigonometric calculations. This plumb line serves two functions: first, it indicates the angular orientation of the instrument, and second, it ensures the instrument is parallel to the vertical plane (perpendicular with the ground) when optically aligned with the target. +Traditionally, the line from the beginning of the arc to the apex is called the jaibs and the line from the end of the arc to the apex is called the jaib tamams. Because the arc is numbered in both directions, these labels are not attached to one straight side or the other, but are instead relative to the measurement or calculation being performed. +Like the arc, both the jaibs and jaib tamams are divided into 60 equal units gathered in groups of five, numbered in both directions to and from the apex. The sixty lines parallel to the jaibs are called sitheeniys or sixtys, and the sixty lines parallel to the jaib tamams are called juyoobul mabsootah. The reason for sixty divisions along the jaibs and jaib tamams is that the instrument uses the sexagesimal number system. It is graduated to the number base 60 and not to the base 10 (decimal system) presently used. Time, angular measurement, and geographical coordinate measurements are about the only holdovers from the Sumerian/Babylonian number system that are still used. +On one of the straight edges of the non-maritime quadrant (solid sheet form) are two alignment plates called hadafatani, each with a small central aperture (pinhole). These two apertures form an optical axis through which the user sights an inclined object, such as a star at night. +The maritime (navigation) version of these devices is skeletal in design rather than a solid sheet form, so as to limit buffeting or movement of the instrument from wind while in the operator's hand. + + +== Measuring the Sun's altitude == + +During the day, the Sun's altitude can be determined by aligning the apertures such that sunlight passes through both and projects a bright illuminated dot onto a surface (such as the user's finger or the screen plate of a mariner's backstaff). The apertures are not viewing holes for sighting the Sun with the naked eye. +The second aperture also attenuates (darkens) the incoming sunlight by masking any annulus-shaped sunlight reflecting off the metal first aperture. This is similar to an iris in a camera lens reducing the light intensity. +Typically, the instrument is orientated such that the user faces looking slightly down upon the scale, with the Sun at the user's left and the right hand placed in such a way that a finger functions as a projection screen. When the apertures are optically aligned with the Sun, the user reads the angular measurement of the point where the graduated arc is bisected by the hanging plumb line. +A misconception by non-astronomers and non-navigators is that using the instrument requires two people: one to take the sight and one to read the plumb line's angular position. Actually, when measuring the Sun's altitude, the instrument is held flush (face on) and below eye level by a single user, meaning they can read the cord's angular position on the face of the instrument. However, it does help to have another person to write down the scale readings as they are taken; the device cannot be held sufficiently stable (retaining the optical alignment) with just one hand. + + +== Gallery == + + +== References == + + +== External links == +Deconstructing the Sine Quadrant-Part 1: Introduction – The Astrolabe Project \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SkyScout-0.md b/data/en.wikipedia.org/wiki/SkyScout-0.md new file mode 100644 index 000000000..76d0b04b2 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SkyScout-0.md @@ -0,0 +1,53 @@ +--- +title: "SkyScout" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SkyScout" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:04.847305+00:00" +instance: "kb-cron" +--- + +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 batteries required sleeves (included) to minimise their electromagnetic interference with GPS signal reception. + + +=== Software === +From an internal database of some 6,000 celestial objects an object is identified simply by centering it in the device's zero-power optical finder and pressing a button. +The database was expandable with extra plug-in SD data cards. A USB connection was also provided for online updates of the object database and device firmware. Since 1 January 2016, the database and firmware can no longer be updated. + + +== Usage == +The SkyScout located celestial objects (trivially including the Earth for ease of accessing audio narration about the planet); the user selected the desired object from the database and red arrows in the viewfinder directed the user to point the viewfinder to the object. The SkyScout also featured a "Tonight's Highlights" mode, leading the user through the night's best objects. + + +== Product lifecycle == + + +=== Release === +The SkyScout was announced at the January 2006 Consumer Electronics Show, and became available in July 2006. It had an initial retail cost of $675, but was later available at prices as low as $250. + + +=== End-of-life === + +The advent of iPhone/Android and associated astronomy apps have somewhat eliminated the need for this device. However, the Skyscout had a low-intensity light system that allowed users' eyes to adapt to the darkness needed for observing stars. +The Celestron SkyScout's database of star and planet positions only extended up to Jan 1, 2016. After this date the SkyScout is not supported by Celestron and no longer works as designed. Because the current date cannot be entered, none of the stars are in the positions that SkyScout indicates if GPS localization is attempted, although of course the stars remain in the same position for time, date and location (the same principle behind a planisphere). Celestron did not indicate this obsolescence date on the product or in the manual. As of April 7, 2019, the Sky Scout can no longer decode the GPS supplied date and time correctly, because of the GPS week number rollover in 2019. + +It is possible to enter the latitude/longitude and time/date manually to continuously use the device, pending firmware. If you are running a later version that runs firmware 3.x.x you are able to manual enter coordinates. To do that immediately after turning on and prior to GPS lock press SELECT and then ENTER TIME/LOCATION MANUALLY. The default year 2005 can be selected since it is impossible to choose any year beyond 2015. Given the planisphere principle just cited that the year is unimportant (for all practical purposes) for stars and deep sky objects, these can still be located successfully using this manual setup. +Firmware updates are not available anymore on Celetron's website and can be found at Vomitron's Website[1]. + + +== References == + + +== External links == +SkyScout website \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Solar_telescope-0.md b/data/en.wikipedia.org/wiki/Solar_telescope-0.md new file mode 100644 index 000000000..7bbc8430f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Solar_telescope-0.md @@ -0,0 +1,42 @@ +--- +title: "Solar telescope" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Solar_telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:06.007214+00:00" +instance: "kb-cron" +--- + +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 tightly-focused sunlight. For this reason, a heat stop is an integral part of the design of solar telescopes. For the Daniel K. Inouye Solar Telescope, the heat load is 2.5 MW/m2, with peak powers of 11.4 kW. The goal of such a heat stop is not only to survive this heat load, but also to remain cool enough not to induce any additional turbulence inside the telescope's dome. +Professional solar observatories may have main optical elements with very long focal lengths (although not always, Dutch Open Telescope) and light paths operating in a vacuum or helium to eliminate air motion due to convection inside the telescope. However, this is not possible for apertures over 1 meter, at which the pressure difference at the entrance window of the vacuum tube becomes too large. Therefore, the Daniel K. Inouye Solar Telescope and the EST have active cooling of the dome to minimize the temperature difference between the air inside and outside the telescope. +Due to the Sun's narrow path across the sky, some solar telescopes are fixed in position (and are sometimes buried underground), with the only moving part being a heliostat to track the Sun. One example of this is the McMath-Pierce Solar Telescope. +The Sun, being the closest star to earth, allows a unique chance to study stellar physics with high-resolution. It was, until the 1990s, the only star whose surface had been resolved. General topics that interest a solar astronomer are its 11-year periodicity (i.e., the Solar Cycle), sunspots, magnetic field activity (see solar dynamo), solar flares, coronal mass ejections, differential rotation, and plasma physics. + +== Other types of observation == +Most solar observatories observe optically at visible, UV, and near infrared wavelengths, but other solar phenomena can be observed — albeit not from the Earth's surface due to the absorption of the atmosphere: + +Solar X-ray astronomy, observations of the Sun in x-rays +Multi-spectral solar telescope array (MSSTA), a rocket launched payload of UV telescopes in the 1990s +Leoncito Astronomical Complex operated a submillimeter wavelength solar telescope. +The Radio Solar Telescope Network (RSTN) is a network of solar observatories maintained and operated by the U.S. Air Force Weather Agency. +CERN Axion Solar Telescope (CAST), looks for solar axions in the early 2000s + +== Amateur == + +In the field of amateur astronomy there are many methods used to observe the Sun. Amateurs use everything from simple systems to project the Sun on a piece of white paper, light blocking filters, Herschel wedges which redirect 95% of the light and heat away from the eyepiece, up to hydrogen-alpha filter systems and even home built spectrohelioscopes. In contrast to professional telescopes, amateur solar telescopes are usually much smaller. +With a conventional telescope, an extremely dark filter at the opening of the primary tube is used to reduce the light of the Sun to tolerable levels. Since the full available spectrum is observed, this is known as "white-light" viewing, and the opening filter is called a "white-light filter". The problem is that even reduced, the full spectrum of white light tends to obscure many of the specific features associated with solar activity, such as prominences and details of the chromosphere. Specialized solar telescopes facilitate clear observation of such H-alpha emissions by using a bandwidth filter implemented with a Fabry-Perot etalon. + +== Solar tower == +A solar tower is a structure used to support equipment for studying the Sun, and is typically part of solar telescope designs. Solar tower observatories are also called vacuum tower telescopes. Solar towers are used to raise the observation equipment above atmospheric turbulence caused by solar heating of the ground and the radiation of the heat into the atmosphere. Traditional observatories do not have to be placed high above ground level, as they do most of their observation at night, when ground radiation is at a minimum. +The horizontal Snow solar observatory was built on Mount Wilson in 1904. It was soon found that heat radiation was disrupting observations. Almost as soon as the Snow Observatory opened, plans were started for a 60-foot-tall (18 m) tower that opened in 1908 followed by a 150-foot (46 m) tower in 1912. The 60-foot tower is currently used to study helioseismology, while the 150-foot tower is active in UCLA's Solar Cycle Program. +The term has also been used to refer to other structures used for experimental purposes, such as the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE), which is being used to study Cherenkov radiation, and the Weizmann Institute solar power tower. +Other solar telescopes that have solar towers are Richard B. Dunn Solar Telescope, Solar Observatory Tower Meudon and others. + +== Selected heliophysics missions == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Solar_telescope-1.md b/data/en.wikipedia.org/wiki/Solar_telescope-1.md new file mode 100644 index 000000000..93420230f --- /dev/null +++ b/data/en.wikipedia.org/wiki/Solar_telescope-1.md @@ -0,0 +1,60 @@ +--- +title: "Solar telescope" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Solar_telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:06.007214+00:00" +instance: "kb-cron" +--- + +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 (1.6 m diameter, 1961–) +McMath–Hulbert Observatory (24"/61 cm diameter, 1941–1979) +Swedish Vacuum Solar Telescope (47.5 cm diameter, 1985–2000) +Swedish 1-m Solar Telescope (1 m diameter, 2002–) +Richard B. Dunn Solar Telescope (0.76 m diameter, 1969–) +Mount Wilson Observatory +Dutch Open Telescope (45 cm diameter, 1997–) +The Teide Observatory hosts multiple solar telescopes, including +the 70 cm Vacuum Tower Telescope (1989–) and +the 1.5 m GREGOR Solar Telescope (2012–). +Goode Solar Telescope (1.6 m, 2009–) +Daocheng Solar Radio Telescope, Chinese radio telescope with 313 parabolic antennas +Daniel K. Inouye Solar Telescope (DKIST), a telescope with 4 m aperture. +European Solar Telescope (EST), a proposed 4-meter class aperture telescope. +Chinese Giant Solar Telescope (CGST), a proposed 5- to 8-meter aperture telescope. +National Large Solar Telescope (NLST), is a Gregorian multi-purpose open telescope proposed to be built and installed in India and aims to study the Sun's microscopic structure. + +== See also == +List of solar telescopes (ground based) +List of heliophysics missions – space telescopes used to observe the Sun +List of telescope types +Coronagraph +Heliostat +Heliometer +Helioscope +Spectroheliograph +Spectrohelioscope +Solar astronomy + +== References == + +== External links == + +Map of solar groundbased observatories and neutron monitors +Schmidt, Wolfgang (2008). "Solar telescopes". Scholarpedia. 3 (4): 4333. Bibcode:2008SchpJ...3.4333S. doi:10.4249/scholarpedia.4333. +CSIRO Solar Heliograph part 2 +Solar Gallery of the Hong Kong Astronomical Society +Lawrence, Pete. "Solar Observing (Part I)". Deep Sky Videos. Brady Haran. +150 ft Solar Tower +60 ft Solar Tower \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Spectroheliograph-0.md b/data/en.wikipedia.org/wiki/Spectroheliograph-0.md new file mode 100644 index 000000000..167c5efe7 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Spectroheliograph-0.md @@ -0,0 +1,28 @@ +--- +title: "Spectroheliograph" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Spectroheliograph" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:08.444385+00:00" +instance: "kb-cron" +--- + +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 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Spectrohelioscope-0.md b/data/en.wikipedia.org/wiki/Spectrohelioscope-0.md new file mode 100644 index 000000000..f802adf25 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Spectrohelioscope-0.md @@ -0,0 +1,26 @@ +--- +title: "Spectrohelioscope" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Spectrohelioscope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:09.572048+00:00" +instance: "kb-cron" +--- + +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 first mirror selects a slice of the Sun, the second selects the desired wavelength. +The spectroheliograph is a similar device, but images the Sun at a particular wavelength photographically and is still in use in professional observatories. + + +== See also == +Helioscope +Heliometer + + +== References == + + +== External links == +An amateur-made spectrohelioscope \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Spider_(polarimeter)-0.md b/data/en.wikipedia.org/wiki/Spider_(polarimeter)-0.md new file mode 100644 index 000000000..6a7a49617 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Spider_(polarimeter)-0.md @@ -0,0 +1,29 @@ +--- +title: "Spider (polarimeter)" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Spider_(polarimeter)" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:11.947346+00:00" +instance: "kb-cron" +--- + +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% of the full sky. The instrument was upgraded with 280 GHz cameras developed by NIST, and flew a second mission in December 2022. The data from these flight produced high signal-to-noise images of the intensity and linear polarization of the Cosmic Microwave Background, with noise levels 3—5 times lower than the Planck spacecraft in the same region of the sky, resulting in precise measurements of the CMB and Galactic foreground radiation, as well as a robust limit on the cosmological tensor-to-scalar ratio. The data provided the first detection of spatial variation in the spectral energy density of polarized Galactic dust emission. + + +== References == + + +== External links == +Group Research Homepage +Spider Homepage +Spider 2014/15 campaign blog +The Spider Collaboration, "A Constraint on Primordial B-Modes from the First Flight of the SPIDER Balloon-Borne Telescope" \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Stonyhurst_disks-0.md b/data/en.wikipedia.org/wiki/Stonyhurst_disks-0.md new file mode 100644 index 000000000..b05766fda --- /dev/null +++ b/data/en.wikipedia.org/wiki/Stonyhurst_disks-0.md @@ -0,0 +1,14 @@ +--- +title: "Stonyhurst disks" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Stonyhurst_disks" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:13.135473+00:00" +instance: "kb-cron" +--- + +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 == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/SuperNova_Early_Warning_System-0.md b/data/en.wikipedia.org/wiki/SuperNova_Early_Warning_System-0.md new file mode 100644 index 000000000..5ac9dd118 --- /dev/null +++ b/data/en.wikipedia.org/wiki/SuperNova_Early_Warning_System-0.md @@ -0,0 +1,43 @@ +--- +title: "SuperNova Early Warning System" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/SuperNova_Early_Warning_System" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:14.343469+00:00" +instance: "kb-cron" +--- + +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 neutrinos: p + e− → n + νe. It is expected that the neutrinos are emitted well before the light from the supernova peaks, so in principle neutrino detectors could give warning to astronomers that a supernova has occurred and may soon be visible. The neutrino pulse from supernova 1987A arrived 3 hours before the associated photons – but SNEWS was not yet active and it was not recognised as a supernova event until after the photons arrived. +Directional precision of approximately 5° is expected. SNEWS is not able to give warning of a Type Ia supernova, as they are not expected to produce significant numbers of neutrinos. Type Ia supernovae, caused by a runaway nuclear fusion reaction in a white dwarf star, are thought to account for roughly one-third of all supernovae. +There are currently seven neutrino detector members of SNEWS: Borexino, Daya Bay, KamLAND, HALO, IceCube, LVD, and Super-Kamiokande. SNEWS began operation prior to 2004, with three members (Super-Kamiokande, LVD, and SNO). The Sudbury Neutrino Observatory is no longer active as it is being upgraded to its successor program SNO+. +The detectors send reports of a possible supernova to a computer at Brookhaven National Laboratory to identify a supernova. If the SNEWS computer identifies signals from two detectors within 10 seconds, the computer will send a supernova alert to observatories around the world to study the supernova. The SNEWS mailing list is open-subscription, and the general public is allowed to sign up; however, the SNEWS collaboration encourages amateur astronomers to instead use Sky and Telescope magazine's AstroAlert service, which is linked to SNEWS. + + +== See also == +Near-Earth supernova +History of supernova observation +Timeline of white dwarfs, neutron stars, and supernovae +Supernova nucleosynthesis +Supernova neutrinos + + +== References == + + +== External links == +Official website of SNEWS 2.0 +Official website of SNEWS +Antonioli, P.; et al. (2004). "SNEWS: the SuperNova Early Warning System". New Journal of Physics. 6: 114. arXiv:astro-ph/0406214. Bibcode:2004NJPh....6..114A. doi:10.1088/1367-2630/6/1/114. S2CID 119431247. +Francis Reddy, "Time for SNEWS", Astronomy 3 June 2005 +NOVA podcast about SNEWS Archived 2006-04-09 at the Wayback Machine (the same in MP3 format) +Weeks, Erin (22 January 2014). "Supernova Explosion in M82: Exciting, but No Neutrinos". Duke University Research Blog. Retrieved 2015-12-06. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Sutton_armillary-0.md b/data/en.wikipedia.org/wiki/Sutton_armillary-0.md new file mode 100644 index 000000000..f683bcd03 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Sutton_armillary-0.md @@ -0,0 +1,42 @@ +--- +title: "Sutton armillary" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Sutton_armillary" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:15.631352+00:00" +instance: "kb-cron" +--- + +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. + +The London Borough of Sutton. + + +== History == +The brief history of the Sutton armillary is that, in the years leading up to the new millennium, the London Borough of Sutton expressed its wish for time-related millennium projects. The Rotary Club responded to this by conceiving, planning and jointly funding the armillary. It was designed to last for years to come, and was originally positioned as the central feature of a Millennium Garden. It was slightly re-positioned in 2011, following a repaving of the pedestrianised High Street area, since when it has stood on the edge of the new central square in the town, directly in front of the Waterstones bookshop. When deciding on the new position, the Rotary Club and the local council had to take account of the need for an adequate supply of sunlight. +The armillary also had to be removed temporarily in November 2012, when it came off its plinth – this received coverage in the local press in a column headed "Time stops in Sutton High Street after Armillary removed". + + +== Benefits to town == + +The armillary's installation has provided a focus for the town centre, and it will remain as a permanent memorial, marking both the new millennium and the important role the Rotary has played in the welfare of Sutton since 1923. + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Swiss_1.2-metre_Leonhard_Euler_Telescope-0.md b/data/en.wikipedia.org/wiki/Swiss_1.2-metre_Leonhard_Euler_Telescope-0.md new file mode 100644 index 000000000..7c2211f3b --- /dev/null +++ b/data/en.wikipedia.org/wiki/Swiss_1.2-metre_Leonhard_Euler_Telescope-0.md @@ -0,0 +1,55 @@ +--- +title: "Swiss 1.2-metre Leonhard Euler Telescope" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Swiss_1.2-metre_Leonhard_Euler_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:16.835986+00:00" +instance: "kb-cron" +--- + +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, SuperWASP. + + +== CORALIE == +The CORALIE spectrograph is an echelle- type spectrograph used for astronomy. It is a copy of the ELODIE spectrograph used by Michel Mayor and Didier Queloz to detect the planet orbiting a star . In April 1998 it was built and installed at the Euler Telescope. Later in 2007 it was upgraded by Didier Queloz and his team to increase its performances to support Wide Angle Search for Planets program and Next-Generation Transit Survey. The instrument is optimized to measure Doppler effect on a star's electromagnetic spectrum with great precision to detect the gravitational tug of an exoplanet orbiting around it. It also known as "radial velocity" or "wobble" method, is an indirect detection method. The mass of the planet can be estimated from these measurements. +The spectrograph participates in the Southern Sky extrasolar Planet search Programme initiated by Michel Mayor +In 2010 visible camera EulerCam was installed by Didier Queloz. Camera main objective was to measure planet by transit method by supporting ground base program such as Wide Angle Search for Planets . The size of an exoplanet can be estimated using the transit method. By combining the measured size and mass from both methods, it can be determined whether the observed exoplanet is gaseous or rocky. + + +=== Characteristics === +The resolution of CORALIE is fixed at R = 50,000 with three-pixel sampling. The detector charge-coupled device is 2k X 2k with a 15 micrometer pixel size. + + +=== Discovered exoplanets === +The first five planetary object discovered using CORALIE are + + +== Gallery == + + +=== Video === + + +== See also == +ELODIE spectrograph +List of largest optical telescopes in the 20th century +Stéphane Udry +WASP-15 + + +== References == + + + +== External links == + +ESO La Silla 1.2m Leonhard Euler Telescope +Southern Sky extrasolar Planet search Programme +The CORALIE survey for southern extrasolar planets +www.exoplanets.ch +University of Geneva – The Geneva Observatory +daviddarling.info /Euler +ESO press release: 4 May 2000 \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Telecompressor-0.md b/data/en.wikipedia.org/wiki/Telecompressor-0.md new file mode 100644 index 000000000..e16fe42b5 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Telecompressor-0.md @@ -0,0 +1,82 @@ +--- +title: "Telecompressor" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Telecompressor" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:17.974207+00:00" +instance: "kb-cron" +--- + +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 {d}{f_{r}}}\right),} + + +where +fo = original focal length of telescope, +d = distance from telecompressor to image plane, and +fr = focal length of telecompressor. +For a reflecting telescope, the calculation is the same. However, since the telecompressor increases the field of view, there could be vignetting in the image, depending on the sizes of the secondary mirror and the telescope tube. +For a catadioptric system that has a combination of mirror and lens, the determination of reduction is more complicated, due to the fact that the telescope has a variable focal length, where the imaging plane can move along the axis of the imaging system. As the addition of the telecompressor will increase the necessary back focus, the original focal length will increase by a certain amount, and then this new focal length would be used in the above formula. + + +== Keplerian (relay) telecompressors == + +Telecompressors were used in early digital SLR systems like the Minolta RD-175 and the Nikon E series. The technology of the time used relatively small sensor sizes, so lenses designed for 35 mm film could not be used with their native field of view without additional optics used. Implementing a telecompressor helped to mitigate these limitations. One effect of a telecompressor is that it reduces the diameter of the image circle, which means that a lens meant for a larger format can be used on a smaller sensor, partially making up for the latter's crop factor. + + +== See also == +Barlow lens +Teleconverter +Convertible lens + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Telescope-0.md b/data/en.wikipedia.org/wiki/Telescope-0.md new file mode 100644 index 000000000..be60e1298 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Telescope-0.md @@ -0,0 +1,37 @@ +--- +title: "Telescope" +chunk: 1/2 +source: "https://en.wikipedia.org/wiki/Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:19.149708+00:00" +instance: "kb-cron" +--- + +A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally, it was an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects – an optical telescope. Nowadays, the word "telescope" is defined as a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors. +The first known practical telescopes were refracting telescopes with glass lenses and were invented in the Netherlands at the beginning of the 17th century. They were used for both terrestrial applications and astronomy. +The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. +In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. + +== Etymology == +The word telescope was coined in 1611 by the Greek mathematician Giovanni Demisiani for one of Galileo Galilei's instruments presented at a banquet at the Accademia dei Lincei. In the Starry Messenger, Galileo had used the Latin term perspicillum. The root of the word is from the Ancient Greek τῆλε, tele 'far' and σκοπεῖν, skopein 'to look or see'; τηλεσκόπος, teleskopos 'far-seeing'. + +== History == + +The earliest existing record of a telescope was a 1608 patent submitted to the government in the Netherlands by Middelburg spectacle maker Hans Lipperhey for a refracting telescope. The actual inventor is unknown but word of it spread through Europe. Galileo heard about it and, in 1609, built his own version, and made his telescopic observations of celestial objects. +The idea that the objective, or light-gathering element, could be a mirror instead of a lens was being investigated soon after the invention of the refracting telescope. The potential advantages of using parabolic mirrors—reduction of spherical aberration and no chromatic aberration—led to many proposed designs and several attempts to build reflecting telescopes. In 1668, Isaac Newton built the first practical reflecting telescope, of a design which now bears his name, the Newtonian reflector. John Dobson invented the Dobsonian telescope in 1956. +The invention of the achromatic lens in 1733 partially corrected color aberrations present in the simple lens and enabled the construction of shorter, more functional refracting telescopes. Reflecting telescopes, though not limited by the color problems seen in refractors, were hampered by the use of fast tarnishing speculum metal mirrors employed during the 18th and early 19th century—a problem alleviated by the introduction of silver coated glass mirrors in 1857, and aluminized mirrors in 1932. The maximum physical size limit for refracting telescopes is about 1 meter (39 inches), dictating that the vast majority of large optical researching telescopes built since the turn of the 20th century have been reflectors. The largest reflecting telescopes currently have objectives larger than 10 meters (33 feet), and work is underway on several 30–40m designs. +The 20th century also saw the development of telescopes that worked in a wide range of wavelengths from radio to gamma-rays. The first purpose-built radio telescope went into operation in 1937. Since then, a large variety of complex astronomical instruments have been developed. + +== In space == + +Since the atmosphere is opaque for most of the electromagnetic spectrum, only a few bands can be observed from the Earth's surface. These bands are visible – near-infrared and a portion of the radio-wave part of the spectrum. For this reason there are no X-ray or far-infrared ground-based telescopes as these have to be observed from orbit. Even if a wavelength is observable from the ground, it might still be advantageous to place a telescope on a satellite due to issues such as clouds, astronomical seeing and light pollution. +The disadvantages of launching a space telescope include cost, size, maintainability and upgradability. +Some examples of space telescopes from NASA are the Hubble Space Telescope that detects visible light, ultraviolet, and near-infrared wavelengths, the Spitzer Space Telescope that detects infrared radiation, and the Kepler Space Telescope that discovered thousands of exoplanets. The latest telescope that was launched was the James Webb Space Telescope on 25 December 2021, in Kourou, French Guiana with an Ariane 5 rocket. The Webb telescope detects infrared light and orbits the L2 Lagrange Point of the earth-sun system. + +== By electromagnetic spectrum == + +The name "telescope" covers a wide range of instruments. Most detect electromagnetic radiation, but there are major differences in how astronomers must go about collecting light (electromagnetic radiation) in different frequency bands. +As wavelengths become longer, it becomes easier to use antenna technology to interact with electromagnetic radiation (although it is possible to make very tiny antenna). The near-infrared can be collected much like visible light; however, in the far-infrared and submillimetre range, telescopes can operate more like a radio telescope. For example, the James Clerk Maxwell Telescope observes from wavelengths from 3 μm (0.003 mm) to 2000 μm (2 mm), but uses a parabolic aluminum antenna. On the other hand, the Spitzer Space Telescope, observing from about 3 μm (0.003 mm) to 180 μm (0.18 mm) uses a mirror (reflecting optics). Also using reflecting optics, the Hubble Space Telescope with Wide Field Camera 3 can observe in the frequency range from about 0.2 μm (0.0002 mm) to 1.7 μm (0.0017 mm) (from ultra-violet to infrared light). +With photons of the shorter wavelengths, with the higher frequencies, glancing-incident optics, rather than fully reflecting optics are used. Telescopes such as TRACE and SOHO use special mirrors to reflect extreme ultraviolet, producing higher resolution and brighter images than are otherwise possible. A larger aperture does not just mean that more light is collected, it also enables a finer angular resolution. +Telescopes may also be classified by location: ground telescope, space telescope, or flying telescope. They may also be classified by whether they are operated by professional astronomers or amateur astronomers. A vehicle or permanent campus containing one or more telescopes or other instruments is called an observatory. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Telescope-1.md b/data/en.wikipedia.org/wiki/Telescope-1.md new file mode 100644 index 000000000..a5d2f67d8 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Telescope-1.md @@ -0,0 +1,70 @@ +--- +title: "Telescope" +chunk: 2/2 +source: "https://en.wikipedia.org/wiki/Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:19.149708+00:00" +instance: "kb-cron" +--- + +=== Radio and submillimeter === + +Radio telescopes are directional radio antennas that typically employ a large dish to collect radio waves. The dishes are sometimes constructed of a conductive wire mesh whose openings are smaller than the wavelength being observed. +Unlike an optical telescope, which produces a magnified image of the patch of sky being observed, a traditional radio telescope dish contains a single receiver and records a single time-varying signal characteristic of the observed region; this signal may be sampled at various frequencies. In some newer radio telescope designs, a single dish contains an array of several receivers; this is known as a focal-plane array. + +By collecting and correlating signals simultaneously received by several dishes, high-resolution images can be computed. Such multi-dish arrays are known as astronomical interferometers and the technique is called aperture synthesis. The 'virtual' apertures of these arrays are similar in size to the distance between the telescopes. As of 2005, the record array size is many times the diameter of the Earth – using space-based very-long-baseline interferometry (VLBI) telescopes such as the Japanese HALCA (Highly Advanced Laboratory for Communications and Astronomy) VSOP (VLBI Space Observatory Program) satellite. +Aperture synthesis is now also being applied to optical telescopes using optical interferometers (arrays of optical telescopes) and aperture masking interferometry at single reflecting telescopes. +Radio telescopes are also used to collect microwave radiation, which has the advantage of being able to pass through the atmosphere and interstellar gas and dust clouds. +Some radio telescopes such as the Allen Telescope Array are used by programs such as SETI and the Arecibo Observatory to search for extraterrestrial life. + +=== Infrared === + +=== Visible light === + +An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum. Optical telescopes increase the apparent angular size of distant objects as well as their apparent brightness. For the image to be observed, photographed, studied, and sent to a computer, telescopes work by employing one or more curved optical elements, usually made from glass lenses and/or mirrors, to gather light and other electromagnetic radiation to bring that light or radiation to a focal point. Optical telescopes are used for astronomy and in many non-astronomical instruments, including: theodolites (including transits), spotting scopes, monoculars, binoculars, camera lenses, and spyglasses. There are three main optical types: + +The refracting telescope which uses lenses to form an image. +The reflecting telescope which uses an arrangement of mirrors to form an image. +The catadioptric telescope which uses mirrors combined with lenses to form an image. +A Fresnel imager is a proposed ultra-lightweight design for a space telescope that uses a Fresnel lens to focus light. +Beyond these basic optical types there are many sub-types of varying optical design classified by the task they perform such as astrographs, comet seekers and solar telescopes. + +=== Ultraviolet === + +Most ultraviolet light is absorbed by the Earth's atmosphere, so observations at these wavelengths must be performed from the upper atmosphere or from space. + +=== X-ray === + +X-rays are much harder to collect and focus than electromagnetic radiation of longer wavelengths. X-ray telescopes can use X-ray optics, such as Wolter telescopes composed of ring-shaped 'glancing' mirrors made of heavy metals that are able to reflect the rays just a few degrees. The mirrors are usually a section of a rotated parabola and a hyperbola, or ellipse. In 1952, Hans Wolter outlined 3 ways a telescope could be built using only this kind of mirror. Examples of space observatories using this type of telescope are the Einstein Observatory, ROSAT, and the Chandra X-ray Observatory. In 2012 the NuSTAR X-ray Telescope was launched which uses Wolter telescope design optics at the end of a long deployable mast to enable photon energies of 79 keV. + +=== Gamma ray === + +Higher energy X-ray and gamma ray telescopes refrain from focusing completely and use coded aperture masks: the patterns of the shadow the mask creates can be reconstructed to form an image. +X-ray and Gamma-ray telescopes are usually installed on high-flying balloons or Earth-orbiting satellites since the Earth's atmosphere is opaque to this part of the electromagnetic spectrum. An example of this type of telescope is the Fermi Gamma-ray Space Telescope which was launched in June 2008. +The detection of very high energy gamma rays, with shorter wavelength and higher frequency than regular gamma rays, requires further specialization. Such detections can be made either with the Imaging Atmospheric Cherenkov Telescopes (IACTs) or with Water Cherenkov Detectors (WCDs). Examples of IACTs are H.E.S.S. and VERITAS with the next-generation gamma-ray telescope, the Cherenkov Telescope Array (CTA), currently under construction. HAWC and LHAASO are examples of gamma-ray detectors based on the Water Cherenkov Detectors. +A discovery in 2012 may allow focusing gamma-ray telescopes. At photon energies greater than 700 keV, the index of refraction starts to increase again. + +== Lists of telescopes == + +== See also == + +== References == + +== Further reading == +Elliott, Robert S. (1966), Electromagnetics, McGraw-Hill +King, Henry C. (1979). The history of the telescope. H. Spencer Jones. New York: Dover Publications. ISBN 0-486-23893-8. OCLC 6025190. +Pasachoff, Jay M. (1981). Contemporary astronomy (2nd ed.). Philadelphia: Saunders College Pub. ISBN 0-03-057861-2. OCLC 7734917. +Rashed, Roshdi; Morelon, Régis (1996), Encyclopedia of the History of Arabic Science, vol. 1 & 3, Routledge, ISBN 978-0-415-12410-2 +Sabra, A. I.; Hogendijk, J. P. (2003). The Enterprise of Science in Islam: New Perspectives. MIT Press. pp. 85–118. ISBN 978-0-262-19482-2. +Wade, Nicholas J.; Finger, Stanley (2001), "The eye as an optical instrument: from camera obscura to Helmholtz's perspective", Perception, 30 (10): 1157–1177, doi:10.1068/p3210, PMID 11721819, S2CID 8185797 +Watson, Fred (2007). Stargazer : the life and times of the telescope. Crows Nest, New South Wales, Australia: Allen & Unwin. ISBN 978-1-74176-392-8. OCLC 173996168. + +== External links == + +Galileo to Gamma Cephei – The History of the Telescope. Archived 8 May 2013 at the Wayback Machine +The Galileo Project – The Telescope by Al Van Helden +"The First Telescopes". Part of an exhibit from Cosmic Journey: A History of Scientific Cosmology. Archived 9 April 2008 at the Wayback Machine by the American Institute of Physics +Taylor, Harold Dennis; Gill, David (1911). "Telescope" . Encyclopædia Britannica. Vol. 26 (11th ed.). pp. 557–573. +Outside the Optical: Other Kinds of Telescopes +Gray, Meghan; Merrifield, Michael (2009). "Telescope Diameter". Sixty Symbols. Brady Haran for the University of Nottingham. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Tellurion-0.md b/data/en.wikipedia.org/wiki/Tellurion-0.md new file mode 100644 index 000000000..107f23755 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Tellurion-0.md @@ -0,0 +1,24 @@ +--- +title: "Tellurion" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Tellurion" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:20.330771+00:00" +instance: "kb-cron" +--- + +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 == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Torquetum-0.md b/data/en.wikipedia.org/wiki/Torquetum-0.md index 3d13825bd..d4e7358c9 100644 --- a/data/en.wikipedia.org/wiki/Torquetum-0.md +++ b/data/en.wikipedia.org/wiki/Torquetum-0.md @@ -4,7 +4,7 @@ chunk: 1/2 source: "https://en.wikipedia.org/wiki/Torquetum" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:38:05.427993+00:00" +date_saved: "2026-05-05T09:42:21.555663+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Torquetum-1.md b/data/en.wikipedia.org/wiki/Torquetum-1.md index 47d10de3e..ba139b93e 100644 --- a/data/en.wikipedia.org/wiki/Torquetum-1.md +++ b/data/en.wikipedia.org/wiki/Torquetum-1.md @@ -4,7 +4,7 @@ chunk: 2/2 source: "https://en.wikipedia.org/wiki/Torquetum" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:38:05.427993+00:00" +date_saved: "2026-05-05T09:42:21.555663+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Triquetrum_(astronomy)-0.md b/data/en.wikipedia.org/wiki/Triquetrum_(astronomy)-0.md index 807b6c63e..59189f5fb 100644 --- a/data/en.wikipedia.org/wiki/Triquetrum_(astronomy)-0.md +++ b/data/en.wikipedia.org/wiki/Triquetrum_(astronomy)-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Triquetrum_(astronomy)" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:38:07.815892+00:00" +date_saved: "2026-05-05T09:42:22.798000+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Verona_astrolabe-0.md b/data/en.wikipedia.org/wiki/Verona_astrolabe-0.md index d3c35bc9c..53c096cfe 100644 --- a/data/en.wikipedia.org/wiki/Verona_astrolabe-0.md +++ b/data/en.wikipedia.org/wiki/Verona_astrolabe-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Verona_astrolabe" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:38:09.037763+00:00" +date_saved: "2026-05-05T09:42:24.032256+00:00" instance: "kb-cron" --- diff --git a/data/en.wikipedia.org/wiki/Versorium-0.md b/data/en.wikipedia.org/wiki/Versorium-0.md new file mode 100644 index 000000000..513942988 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Versorium-0.md @@ -0,0 +1,34 @@ +--- +title: "Versorium" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Versorium" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:40.058809+00:00" +instance: "kb-cron" +--- + +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 to point at a nearby charged object due to charges induced in the ends of the needle by the external charge, through electrostatic induction. For example, if a positively charged object is brought near, the mobile negative charges in the metal will be attracted to it, and move to the end of the needle nearest the object. The attractive force on these negative charges will then turn the needle until the end is nearest to the charged object, when it will stop. Conversely the positive charges in the needle will be repelled, and move to the far end of the needle. The repulsive forces will then push this end of the needle as far away from the object as possible. The result, after the needle stops swinging, is that the axis of the needle points through the object. +Either end of the needle can be attracted to the charged object; whichever happens to be nearest will turn to point at it. So the two ends of the needle are symmetric as far as its action is concerned. The versorium needle also responds identically regardless of the polarity of the attracting charge, so it cannot distinguish between a positive and a negative charge, unlike a compass needle, which has a "North" and "South" end which can distinguish between the "North" and "South" pole of a magnet. + + +== Impact == +Gilbert used the versorium to test whether different materials were "elektrics" (insulators, in modern terms) or non-"elektrics" (conductors). While he didn't devise a theory to explain his findings, it was a good example of how science was starting to change by incorporating empirical studies at the dawn of the Age of Reason. A century and a half later, Andrew Gordon constructed what seems to have been the first electric motor, which was based on Gilbert's device. His design was a double versorium, shaped like a swastika which rotated when a charged body was brought near. +Building a versorium is a suggested exercise in science classes in many elementary schools. One reason is that the operation of the versorium is simple to understand and the device is suitable for building by even young students, but can still be used to illustrate many important concepts in electricity. The versorium can easily be built using household materials. + + +== See also == +Static electricity +Electrometer + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph-0.md b/data/en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph-0.md new file mode 100644 index 000000000..76f56e253 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph-0.md @@ -0,0 +1,25 @@ +--- +title: "Visible Multi Object Spectrograph" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Visible_Multi_Object_Spectrograph" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:25.209834+00:00" +instance: "kb-cron" +--- + +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 the Very Large Telescope + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Volvelle-0.md b/data/en.wikipedia.org/wiki/Volvelle-0.md new file mode 100644 index 000000000..abc8fde18 --- /dev/null +++ b/data/en.wikipedia.org/wiki/Volvelle-0.md @@ -0,0 +1,39 @@ +--- +title: "Volvelle" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Volvelle" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:26.363356+00:00" +instance: "kb-cron" +--- + +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 to verb conjugation. They anticipate animal breeding cycles and calculate radiation exposure, measure chocolate consumption and quantify bridge tips, chart bird calls, convert metrics, and calculate taxes. There are fortune-telling wheels and semaphore-charting wheels; emergency first-aid wheels and electronic fix-it wheels; playful wheels that test phonetics and prophylactic wheels that prevent pregnancy. +The rock band Led Zeppelin employed a volvelle in the sleeve design for the album Led Zeppelin III (1970). +Two games from the game company Infocom included volvelles inside their package as "feelies": Sorcerer (1983) and A Mind Forever Voyaging (1985). Both volvelles served to impede copying of the games, because they contained information needed to play the game. Other games included similar code wheels. + + +== See also == +E6B +Ramon Llull +Planisphere +Pop-up book +Slide chart +Zairja + + +== References == + + +== Further reading == +Eye, No. 41, Vol. 11, edited by John L. Walters, Quantum Publishing, Autumn 2001. +Lindberg, Sten G. "Mobiles in Books: Volvelles, Inserts, Pyramids, Divinations, and Children's Games". The Private Library, 3rd series 2.2 (1979): 49. +"New Volvelle Exhibit in NYC". robertsabuda.com. 2004. Archived from the original on 2010-01-14. An exhibition of volvelles at New York's Grolier Club. +Crupi, Gianfranco (2019). "Volvelles of knowledge. Origin and development of an instrument of scientific imagination (13th-17th centuries)". JLIS.it. 10 (2). doi:10.4403/jlis.it-12534. Archived from the original on 2020-11-28. Retrieved 2019-05-28. \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Warkworth_Radio_Astronomical_Observatory-0.md b/data/en.wikipedia.org/wiki/Warkworth_Radio_Astronomical_Observatory-0.md new file mode 100644 index 000000000..9d1e62deb --- /dev/null +++ b/data/en.wikipedia.org/wiki/Warkworth_Radio_Astronomical_Observatory-0.md @@ -0,0 +1,30 @@ +--- +title: "Warkworth Radio Astronomical Observatory" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Warkworth_Radio_Astronomical_Observatory" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:27.517774+00:00" +instance: "kb-cron" +--- + +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 radio noise, and the horizon elevation of only 5° allowed the station to be useful for transmissions to low orbit satellites. The original 30-metre antenna was decommissioned on 18 June 2008 and demolished. +A second antenna and station building were opened on 24 July 1984. This was removed from commercial service in November 2010, after which the Auckland University of Technology upgraded the motor drives and began using it for radio astronomy. + + +== Technical information == +A hydrogen maser is installed on-site to provide the very accurate timing required by VLBI observations. The observatory has a 10 Gbit/s connection to the REANNZ network, providing high speed data transfers for files and e-VLBI as well as linking the site to the global national research and education network architecture. + + +== See also == +Radio astronomy +List of radio telescopes + + +== References == \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Warkworth_Radio_Telescope-0.md b/data/en.wikipedia.org/wiki/Warkworth_Radio_Telescope-0.md new file mode 100644 index 000000000..c6c185abb --- /dev/null +++ b/data/en.wikipedia.org/wiki/Warkworth_Radio_Telescope-0.md @@ -0,0 +1,38 @@ +--- +title: "Warkworth Radio Telescope" +chunk: 1/1 +source: "https://en.wikipedia.org/wiki/Warkworth_Radio_Telescope" +category: "reference" +tags: "science, encyclopedia" +date_saved: "2026-05-05T09:42:28.752570+00:00" +instance: "kb-cron" +--- + +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 International VLBI Service for Geodesy and Astrometry. It is also co-located with a Land Information New Zealand and GNS Science 'PositioNZ' Global Navigation Satellite System station, to assist in maintaining the International Terrestrial Reference Frame. + + +== See also == +Warkworth Radio Astronomical Observatory +Warkworth 30m Radio Telescope +Radio astronomy +Radio telescope +List of radio telescopes + + +== References == + + +== External links == +http://www.irasr.aut.ac.nz \ No newline at end of file diff --git a/data/en.wikipedia.org/wiki/Wimshurst_machine-0.md b/data/en.wikipedia.org/wiki/Wimshurst_machine-0.md index 32aacaeeb..8bfc2db2a 100644 --- a/data/en.wikipedia.org/wiki/Wimshurst_machine-0.md +++ b/data/en.wikipedia.org/wiki/Wimshurst_machine-0.md @@ -4,7 +4,7 @@ chunk: 1/1 source: "https://en.wikipedia.org/wiki/Wimshurst_machine" category: "reference" tags: "science, encyclopedia" -date_saved: "2026-05-05T09:38:11.370553+00:00" +date_saved: "2026-05-05T09:42:41.290766+00:00" instance: "kb-cron" ---