An equatorium (plural, equatoria) is an astronomicalcalculating instrument. It can be used for finding the positions of the Moon, Sun, and planets without arithmetic operations, using a geometrical model to represent the position of a given celestial body.
Planetary equatoria were probably made by ancient Greeks, although no findings nor descriptions have been preserved from that period. In his comment on Ptolemy's Handy Tables, 4th century mathematician Theon of Alexandria introduced some diagrams to geometrically compute the position of the planets based on Ptolemy's epicyclical theory. The first description of the construction of a solar (as opposed to planetary) equatorium is contained in Proclus's fifth-century work Hypotyposis,[1] where he gives instructions on how to construct one in wood or bronze.[2]
The earliest surviving descriptions of planetary equatoria are the Latin translations of Arab works contained in the Libros del saber de astronomia (Books of the knowledge of astronomy), a Castilian compilation of astronomical works collected under the patronage of Alfonso X of Castile in the thirteenth century: an early eleventh century text by Ibn al‐Samḥ and a 1080/1081[3] treatise by al-Zarqālī.[2]
The Theorica Planetarum (c. 1261–1264) by Campanus of Novara is the earliest extant description of the construction of an equatorium in Latin Europe.[4] Campanus' instrument resembled an astrolabe, with several interchangeable plates within a mater. The best manuscripts of Campanus' treatise contain paper and parchment equatoria with moveable parts.[2]
Variations
A 1600 equatorium, possibly from France
The history of the equatorium does not just end after the 11th century, but it inspired a more diverse invention called “The Albion”. The Albion is an astronomical instrument invented by Richard of Wallingford at the beginning of the 14th century.[5] It has various functional uses such as that of the equatorium for planetary and conjunction computations. It can calculate when eclipses will occur. The Albion is made up of 18 different scales which makes it extremely complex in comparison to the equatorium. The history of this instrument is still disputed to this day, as the only Albion from the past is both unnamed and unmarked.[5]
Astrolabe compared with equatorium
The roots of the equatorium lie in the astrolabe. The history of the astrolabe dates back to roughly 220 BC in the works of Hipparchus.[6] The difference between the two instruments is that the astrolabe measures the time and position of the sun and stars at a specific location in time.[7] In contrast, the equatorium is used to calculate the past or future positions of the planets and celestial bodies according to the planetary theory of Ptolemy.
Uses
The equatorium can further be specialized depending on the epicycle. There are three possible epicycles that can be adjusted to serve for planetary positions in three groups: the moon, the stars, and the sun. The sun was considered a planet in the Ptolemaic system, hence why the equatorium could be used to determine its position.[8] Through the use of Ptolemy's model, astronomers were able to make a single instrument with various capabilities that catered to the belief that the solar system had the earth at the center. In fact, specialized equatoriums had astrological aspects of medicine, as the orientation of planets gave insight to zodiac signs which helped some doctors cater medical treatments to patients.
At least 15 minutes was needed to calculate the planetary position with the use of a table for each celestial body.[9] A horoscope of that era would have required the positions of seven astronomical objects, requiring nearly two hours of manual calculation time.
See also
Wikimedia Commons has media related to Equatorium.
^Proclus (1909). Hypotyposis Astronomicarum Positionum. Bibliotheca scriptorum Graecorum et Romanorum Teubneriana. Karl Manitius (ed.). Leipzig: Teubner.
^Toomer, G. J. (1971). "Campanus of Novara". In Gillispie, Charles Coulston (ed.). Dictionary of scientific biography. Vol. III. New York: Scribner. pp. 23–29. ISBN978-0-684-10114-9.
^ abTruffa, Giancarlo. "The Albion of Rome. A unique example of Medieval Equatorium". {{cite journal}}: Cite journal requires |journal= (help)
^"Third Solution: The Equant Point - SliderBase". www.sliderbase.com. Retrieved 2018-05-09.
^"the definition of astrolabe". Dictionary.com. Retrieved 2018-05-09.
^Colledge, Eric (1955). "The Equatorium of the Planets". Blackfriars. 36 (424–5): 276–284. doi:10.1111/j.1741-2005.1955.tb00671.x. JSTOR 43816789.
^Fosmire, Michael (2014). "Richard of Wallingford". Biographical Encyclopedia of Astronomers. Springer, New York, NY. pp. 1831–1832. doi:10.1007/978-1-4419-9917-7_1167. ISBN978-1-4419-9916-0.
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For the African province see Equatoria This article may require cleanup to meet Wikipedia s quality standards The specific problem is tone and other issues improve sourcing Please help improve this article if you can July 2018 Learn how and when to remove this template message An equatorium plural equatoria is an astronomical calculating instrument It can be used for finding the positions of the Moon Sun and planets without arithmetic operations using a geometrical model to represent the position of a given celestial body Equatorium from Johannes Schoner Contents 1 History 2 Variations 3 Astrolabe compared with equatorium 4 Uses 5 See also 6 References 7 Further readingHistory EditPlanetary equatoria were probably made by ancient Greeks although no findings nor descriptions have been preserved from that period In his comment on Ptolemy s Handy Tables 4th century mathematician Theon of Alexandria introduced some diagrams to geometrically compute the position of the planets based on Ptolemy s epicyclical theory The first description of the construction of a solar as opposed to planetary equatorium is contained in Proclus s fifth century work Hypotyposis 1 where he gives instructions on how to construct one in wood or bronze 2 The earliest surviving descriptions of planetary equatoria are the Latin translations of Arab works contained in the Libros del saber de astronomia Books of the knowledge of astronomy a Castilian compilation of astronomical works collected under the patronage of Alfonso X of Castile in the thirteenth century an early eleventh century text by Ibn al Samḥ and a 1080 1081 3 treatise by al Zarqali 2 The Theorica Planetarum c 1261 1264 by Campanus of Novara is the earliest extant description of the construction of an equatorium in Latin Europe 4 Campanus instrument resembled an astrolabe with several interchangeable plates within a mater The best manuscripts of Campanus treatise contain paper and parchment equatoria with moveable parts 2 Variations Edit A 1600 equatorium possibly from France The history of the equatorium does not just end after the 11th century but it inspired a more diverse invention called The Albion The Albion is an astronomical instrument invented by Richard of Wallingford at the beginning of the 14th century 5 It has various functional uses such as that of the equatorium for planetary and conjunction computations It can calculate when eclipses will occur The Albion is made up of 18 different scales which makes it extremely complex in comparison to the equatorium The history of this instrument is still disputed to this day as the only Albion from the past is both unnamed and unmarked 5 Astrolabe compared with equatorium EditThe roots of the equatorium lie in the astrolabe The history of the astrolabe dates back to roughly 220 BC in the works of Hipparchus 6 The difference between the two instruments is that the astrolabe measures the time and position of the sun and stars at a specific location in time 7 In contrast the equatorium is used to calculate the past or future positions of the planets and celestial bodies according to the planetary theory of Ptolemy Uses EditThe equatorium can further be specialized depending on the epicycle There are three possible epicycles that can be adjusted to serve for planetary positions in three groups the moon the stars and the sun The sun was considered a planet in the Ptolemaic system hence why the equatorium could be used to determine its position 8 Through the use of Ptolemy s model astronomers were able to make a single instrument with various capabilities that catered to the belief that the solar system had the earth at the center In fact specialized equatoriums had astrological aspects of medicine as the orientation of planets gave insight to zodiac signs which helped some doctors cater medical treatments to patients At least 15 minutes was needed to calculate the planetary position with the use of a table for each celestial body 9 A horoscope of that era would have required the positions of seven astronomical objects requiring nearly two hours of manual calculation time See also Edit Wikimedia Commons has media related to Equatorium Antikythera mechanism Armillary sphere Astrarium Astrolabe Astronomical clock Orrery Planetarium Torquetum The equatorie of the planetisReferences Edit Proclus 1909 Hypotyposis Astronomicarum Positionum Bibliotheca scriptorum Graecorum et Romanorum Teubneriana Karl Manitius ed Leipzig Teubner a b c Evans James 1998 The History and Practice of Ancient Astronomy Oxford amp New York Oxford University Press p 404 ISBN 978 0 19 509539 5 Zarqali islamsci mcgill ca Retrieved 2018 05 09 Toomer G J 1971 Campanus of Novara In Gillispie Charles Coulston ed Dictionary of scientific biography Vol III New York Scribner pp 23 29 ISBN 978 0 684 10114 9 a b Truffa Giancarlo The Albion of Rome A unique example of Medieval Equatorium a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Third Solution The Equant Point SliderBase www sliderbase com Retrieved 2018 05 09 the definition of astrolabe Dictionary com Retrieved 2018 05 09 Colledge Eric 1955 The Equatorium of the Planets Blackfriars 36 424 5 276 284 doi 10 1111 j 1741 2005 1955 tb00671 x JSTOR 43816789 Fosmire Michael 2014 Richard of Wallingford Biographical Encyclopedia of Astronomers Springer New York NY pp 1831 1832 doi 10 1007 978 1 4419 9917 7 1167 ISBN 978 1 4419 9916 0 Further reading EditSeb Falk s blog making a planetary equatorium Portals Astronomy Stars Spaceflight Outer space Solar System Retrieved from https en wikipedia org w index php title Equatorium amp oldid 1100776145, wikipedia, wiki, book, books, library,
