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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Astrolabe | 2/5 | https://en.wikipedia.org/wiki/Astrolabe | reference | science, encyclopedia | 2026-05-05T09:40:07.689542+00:00 | kb-cron |
The spherical astrolabe was a variation of both the astrolabe and the armillary sphere, invented during the Middle Ages by astronomers and inventors in the Islamic world. The earliest description of the spherical astrolabe dates to Al-Nayrizi (fl. 892–902). In the 12th century, Sharaf al-Dīn al-Tūsī invented the linear astrolabe, sometimes called the "staff of al-Tusi", which was
"a simple wooden rod with graduated markings, but without sights. It was furnished with a plumb line and a double chord for making angular measurements and bore a perforated pointer". The geared mechanical astrolabe was invented by Abi Bakr of Isfahan in 1235. The first known metal astrolabe in Western Europe is the Destombes astrolabe made from brass in the eleventh century in Portugal. Metal astrolabes avoided the warping that large wooden ones were prone to, allowing the construction of larger and therefore more accurate instruments. Metal astrolabes were heavier than wooden instruments of the same size, making it difficult to use them in navigation.
Herman Contractus of Reichenau Abbey, examined the use of the astrolabe in Mensura Astrolai during the 11th century. Peter of Maricourt wrote a treatise on the construction and use of a universal astrolabe in the last half of the 13th century entitled Nova compositio astrolabii particularis. Universal astrolabes can be found at the History of Science Museum, Oxford. David A. King, historian of Islamic instrumentation, describes the universal astrolobe designed by Ibn al-Sarraj of Aleppo (a.k.a. Ahmad bin Abi Bakr; fl. 1328) as "the most sophisticated astronomical instrument from the entire Medieval and Renaissance periods". English author Geoffrey Chaucer (c. 1343–1400) compiled A Treatise on the Astrolabe for his son, mainly based on a work by Messahalla or Ibn al-Saffar. The same source was translated by French astronomer and astrologer Pélerin de Prusse and others. The first printed book on the astrolabe was Composition and Use of Astrolabe by Christian of Prachatice, also using Messahalla, but relatively original. A simplified astrolabe, known as a balesilha, was used by sailors to get an accurate reading of latitude while at sea. The use of the balesilha was promoted by Prince Henry (1394–1460) while navigating for Portugal.
The astrolabe was almost certainly first brought north of the Pyrenees by Gerbert of Aurillac (future Pope Sylvester II), where it was integrated into the quadrivium at the school in Reims, France, sometime before the turn of the 11th century. In the 15th century, French instrument maker Jean Fusoris (c. 1365–1436) also started remaking and selling astrolabes in his shop in Paris, along with portable sundials and other popular scientific devices of the day. Thirteen of his astrolabes survive to this day. One more special example of craftsmanship in early 15th-century Europe is the astrolabe designed by Antonius de Pacento and made by Dominicus de Lanzano, dated 1420. In the 16th century, Johannes Stöffler published Elucidatio fabricae ususque astrolabii, a manual of the construction and use of the astrolabe. Four identical 16th century astrolabes made by Georg Hartmann provide some of the earliest evidence for batch production by division of labor. Greek painter Ieremias Palladas incorporated a sophisticated astrolabe in his 1612 painting depicting Catherine of Alexandria. The painting, entitled Catherine of Alexandria, in addition to the saint, showed a device labelled the 'system of the universe' (Σύστημα τοῦ Παντός). The device featured the classical planets with their Greek names: Helios (Sun), Selene (Moon), Hermes (Mercury), Aphrodite (Venus), Ares (Mars), Zeus (Jupiter), and Cronos (Saturn). The depicted device also had celestial spheres, following the Ptolemaic model, and Earth was shown as a blue sphere with circles of geographic coordinates. A complicated line representing the axis of the Earth covered the entire instrument.
=== Sanskrit works ===
==== Yantrarāja ====
In 1370, the first Indian treatise on the astrolabe was written by the Jain astronomer Mahendra Suri, titled Yantrarāja. With the support and patronage of Firuz Shah Tughlaq, Mahendra Sūri composed the first ever Sanskrit manual on astrolabes. It was Sūri who coined the Sanskrit name "Yantrarāja" ("the king of astronomical instruments") for the astrolabe and he also titled his manual on astrolabes as Yantrarāja. Sūri composed the manual in 1370 CE. Mahendra Sūri's student Malayendu Sūri composed a commentary on Yantrarāja in 1382. Two other commentaries on Yantrarāja are known, one by Gopirāja written in 1540 and other by Yajñeśvara in 1842. The Yantrarāja manual in 128 verses is divided into five chapters. The first chapter Gaṇitādhyāya discusses the theory behind the astrolabe. The second chapter Yantraghatanādhyāya is devoted to descriptions of the various components of the astrolabe. The third chapter Yantraracanādhyāya describes the details of the construction of the astrolabe. The fourth chapter Yantrasodhanādhyāya discusses method for ascertaining whether the astrolabe has been properly constructed. It is in the fifth and final chapter Yantravicāraṇādhyāya one can see descriptions on how to use the instrument for observational and computational purposes. This chapter also dwells on the different types of astronomical and trigonometrical problems that can be solved using the astrolabe. While Mahendra Sūri's manual is in 128 verses and contains no data in the form of tables, Malayendu Sūri's commentary is interspersed with neatly prepared tables.
==== Other Sanskrit works on astrolabe ==== Over the centuries since the publication of Mahendra Sūri's Yantrarāja in 1370, several other Sanskrit manuals on the astrolabe have been composed. These include the following:
Yantra-rāja-adhikāra (Chapter 1 of Yantrakiraṇāvalī) by Padmanābha in 1423 Turya-yantra-prakāśa by Bhūdhara in 1572 Yantrarāja-vicāra-vimśādhyāyī by Nayanasukhopādhyāya in 1730 Yantrarāja-racanā by Savāī Jaya Siṃha (1688 - 1743) yantrarāja-kalpa by Mathurānātha Śukla (1782)
=== Astrolabes and clocks ===