Editing Astronomical clock (section)

== History ==
{{Main|History of timekeeping devices}}
[[File:Louis de Bruges in front of an astronomical clock Henri Suso, Horloge de Sapience 1470-1480.jpg|thumb|upright=1.3|The courtier and bibliophile [[Louis de Gruuthuse]] in front of an astronomical clock. Henri Suso, ''Horloge de Sapience'', 1470-1480]]
The [[Antikythera mechanism]] is the oldest known analog computer and a precursor to astronomical clocks. A complex arrangement of multiple gears and gear trains could perform functions such as determining the position of the [[sun]], [[moon]] and [[planet]]s, predict [[eclipse]]s and other astronomical phenomena and tracking the dates of [[Olympic Games]].<ref>{{Cite journal |last1=Freeth |first1=Tony |last2=Higgon |first2=David |last3=Dacanalis |first3=Aris |last4=MacDonald |first4=Lindsay |last5=Georgakopoulou |first5=Myrto |last6=Wojcik |first6=Adam |date=2021-03-12 |title=A Model of the Cosmos in the ancient Greek Antikythera Mechanism |journal=Scientific Reports |language=en |volume=11 |issue=1 |pages=5821 |doi=10.1038/s41598-021-84310-w |pmid=33712674 |pmc=7955085 |bibcode=2021NatSR..11.5821F |issn=2045-2322}}</ref> Research in 2011 and 2012 led an expert group of researchers to posit that European astronomical clocks are descended from the technology of the Antikythera mechanism.<ref>PBS (2013). [https://www.pbs.org/wgbh/nova/ancient/ancient-computer.html ''NOVA'': "Ancient Computer"]. Retrieved 4 April 2013.</ref>

In the 11th century, the [[Song dynasty]] Chinese horologist, mechanical engineer, and astronomer [[Su Song]] created a [[water clock|water-driven astronomical clock]] for his clock-tower of [[Kaifeng]] City. Su Song is noted for having incorporated an [[escapement]] mechanism and the earliest known endless power-transmitting [[chain drive]] for his clock-tower and [[armillary sphere]] to function. Contemporary [[Islamic astronomy|Muslim astronomers]] and [[Muslim inventions|engineers]] also constructed a variety of highly accurate astronomical clocks for use in their [[Observatory|observatories]],<ref>Kasem Ajram (1992). ''Miracle of Islamic Science'', Appendix B. Knowledge House Publishers. {{ISBN|0-911119-43-4}}.</ref><ref>{{cite book|url=https://books.google.com/books?id=ZDejQaioG00C&pg=PA47|title=Early Orientalism|isbn=9781136578915|last1=Kalmar|first1=Ivan|date=17 June 2013|publisher=Routledge }}</ref><ref>{{cite journal|last=Hill |first=Donald R. |author-link=Donald Routledge Hill |title=Mechanical Engineering in the Medieval Near East |journal=Scientific American |date = May 1991|volume=264 |issue=5 |pages=64–69 |doi=10.1038/scientificamerican0591-100 |bibcode=1991SciAm.264e.100H }} ([[cf.]] {{cite web|last=Hill |first=Donald R. |author-link=Donald Routledge Hill |url=http://home.swipnet.se/islam/articles/HistoryofSciences.htm |title=Mechanical Engineering |access-date=22 January 2008 |archive-url=https://web.archive.org/web/20071225091836/http://home.swipnet.se/islam/articles/HistoryofSciences.htm |archive-date=25 December 2007 |url-status=live  }})</ref> such as the [[Astrolabe|astrolabic]] clock by [[Ibn al-Shatir]] in the early 14th century.<ref>David A. King (1983). "The Astronomy of the Mamluks", ''[[Isis (journal)|Isis]]'' '''74''' (4), p. 531-555 [545–546].</ref><ref>{{Citation |last=Marks |first=William E. |title=Water Clocks |date=2005-04-15 |url=https://onlinelibrary.wiley.com/doi/10.1002/047147844X.wh21 |encyclopedia=Water Encyclopedia |pages=704–707 |editor-last=Lehr |editor-first=Jay H. |place=Hoboken, NJ, USA |publisher=John Wiley & Sons, Inc. |language=en |doi=10.1002/047147844x.wh21 |isbn=978-0-471-47844-7 |access-date=2022-11-08 |editor2-last=Keeley |editor2-first=Jack|url-access=subscription }}</ref>

The early development of mechanical clocks in Europe is not fully understood, but there is general agreement that by 1300–1330 there existed mechanical clocks (powered by weights rather than by water and using an [[escapement]]) which were intended for two main purposes: for signalling and notification (e.g. the timing of services and public events), and for modelling the solar system. The latter is an inevitable development because the [[astrolabe]] was used both by astronomers and astrologers, and it was natural to apply a clockwork drive to the rotating plate to produce a working model of the solar system. American historian [[Lynn Townsend White Jr.|Lynn White Jr.]] of Princeton University wrote:<ref>{{cite book| last=White | first=Lynn Jr. | title=Medieval Technology and Social Change | year=1966 | publisher=Oxford Press}}, p.122-123</ref> {{cquote|Most of the first clocks were not so many chronometers as exhibitions of the pattern of the cosmos … Clearly, the origins of the mechanical clock lie in a complex realm of monumental planetaria, equatoria, and astrolabes.
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The astronomical clocks developed by the English mathematician and cleric [[Richard of Wallingford]] in [[St Albans]] during the 1330s,<ref>{{cite web|last=Whyte|first=Nicholas|title=The Astronomical Clock of Richard of Wallingford|publisher=personal website|url=http://www.nicholaswhyte.info/row.htm|access-date=24 April 2008| archive-url= https://web.archive.org/web/20080504082935/http://www.nicholaswhyte.info/row.htm| archive-date= 4 May 2008 | url-status= live}}</ref> and by medieval Italian physician and astronomer Giovanni Dondi dell'Orologio in [[Padua]] between 1348 and 1364<ref name="Astrarium">{{cite web|last=Burnett-Stuart|first=George|title=De Dondi's Astrarium|work=Almagest|publisher=Computastat Group Ltd.|url=http://www.almagest.co.uk/middle/astrar.htm|access-date=21 April 2008|archive-url=https://web.archive.org/web/20080530194815/http://www.almagest.co.uk/middle/astrar.htm|archive-date=30 May 2008|url-status=dead}}</ref> are masterpieces of their type. They no longer exist, but detailed descriptions of their design and construction survive, and modern reproductions have been made. Wallingford's clock may have shown the sun, moon (age, [[lunar phase|phase]], and [[lunar node|node]]), stars and planets, and had, in addition, a wheel of fortune and an indicator of the state of the tide at [[London Bridge]]. De Dondi's clock was a seven-faced construction with 107 moving parts, showing the positions of the sun, moon, and five planets, as well as religious feast days.<ref name="Astrarium" />

Both these clocks, and others like them, were probably less accurate than their designers would have wished. The gear ratios may have been exquisitely calculated, but their manufacture was somewhat beyond the mechanical abilities of the time, and they never worked reliably. Furthermore, in contrast to the intricate advanced wheelwork, the timekeeping mechanism in nearly all these clocks until the 16th century was the simple [[verge and foliot]] escapement, which had errors of at least half an hour a day.<ref>{{Cite web |title=Verge and Foliot Escapement |url=https://digital.library.cornell.edu/catalog/ss:29272029 |access-date=2022-11-08 |website=digital.library.cornell.edu |language=en}}</ref><ref>{{Cite web |title=Mechanism for a bell tower clock with verge escapement and foliot |url=https://mostre.museogalileo.it/motoperpetuo/en/after-leonardo/between-uncertainty-and-fraud/mechanism-for-a-bell-tower-clock-with-verge-escapement-and-foliot.html |access-date=2022-11-08 |website=mostre.museogalileo.it}}</ref>

Astronomical clocks were built as demonstration or exhibition pieces, to impress as much as to educate or inform. The challenge of building these masterpieces meant that clockmakers would continue to produce them, to demonstrate their technical skill and their patrons' wealth. The philosophical message of an ordered, heavenly-ordained universe, which accorded with the Gothic-era view of the world, helps explain their popularity.

The growing interest in astronomy during the 18th century revived interest in astronomical clocks, less for the philosophical message, more for the accurate astronomical information that [[pendulum]]-regulated clocks could display.