Editing History of astronomy (section)

==Ancient times==
===Mesopotamia===
{{Main|Babylonian astronomy}}
{{Further|Babylonian astrology|Babylonian calendar}}

[[File:Babylonian tablet recording Halley's comet.jpg|thumb|upright|Babylonian tablet in the [[British Museum]] recording [[Halley's Comet]] in 164&nbsp;BC]]

The origins of astronomy can be found in [[Mesopotamia]], the "land between the rivers" [[Tigris]] and [[Euphrates]], where the ancient kingdoms of [[Sumer]], [[Assyria]], and [[Babylonia]] were located. A form of writing known as [[cuneiform]] emerged among the Sumerians around 3500–3000 BC. Our knowledge of Sumerian astronomy is indirect, via the earliest Babylonian star catalogues dating from about 1200&nbsp;BC. The fact that many star names appear in Sumerian suggests a continuity reaching into the Early Bronze Age. [[Astral theology]], which gave planetary gods an important role in [[Mesopotamian mythology]] and [[Mesopotamian religion|religion]], began with the [[Sumer]]ians. They also used a [[sexagesimal]] (base 60) place-value number system, which simplified the task of recording very large and very small numbers. The modern practice of dividing a circle into 360 [[degree (angle)|degrees]], or an hour into 60 minutes, began with the Sumerians. For more information, see the articles on [[Babylonian numerals]] and [[Babylonian mathematics|mathematics]].

Mesopotamia is worldwide the place of the earliest known astronomer and poet by name: [[Enheduanna]], [[Akkadian Empire|Akkadian]] high priestess to the [[lunar deity]] [[Sin (mythology)|Nanna/Sin]] and princess, daughter of [[Sargon the Great]] ({{circa|2334}} &ndash; {{circa|2279}} BCE). She had the Moon tracked in her chambers and wrote poems about her divine Moon.<ref name="c099">{{cite magazine | last=Winkler | first=Elizabeth | title=The Struggle to Unearth the World's First Author | magazine=The New Yorker | date=2022-11-19 | url=https://www.newyorker.com/books/page-turner/the-struggle-to-unearth-the-worlds-first-author | access-date=2025-02-10}}</ref>

Classical sources frequently use the [[wikt:Chaldean|term Chaldeans]] for the astronomers of Mesopotamia, who were originally [[Ancient Chaldeans|a people]], before being identified with priest-scribes specializing in [[astrology]] and other forms of [[divination]].

The first evidence of recognition that astronomical phenomena are periodic and of the application of mathematics to their prediction is Babylonian. Tablets dating back to the [[First Babylonian dynasty|Old Babylonian period]] document the application of mathematics to the variation in the length of daylight over a solar year. Centuries of Babylonian observations of celestial phenomena are recorded in the series of [[cuneiform]] tablets known as the ''[[Enūma Anu Enlil]]''. The oldest significant astronomical text that we possess is Tablet 63 of the ''Enūma Anu Enlil'', the [[Venus tablet of Ammisaduqa|Venus tablet]] of [[Ammi-saduqa]], which lists the first and last visible risings of Venus over a period of about 21 years and is the earliest evidence that the phenomena of a planet were recognized as periodic. The [[MUL.APIN]] contains catalogues of stars and constellations as well as schemes for predicting [[heliacal rising]]s and the settings of the planets, lengths of daylight measured by a [[water clock]], [[gnomon]], shadows, and [[Intercalation (timekeeping)|intercalations]]. The Babylonian GU text arranges stars in 'strings' that lie along declination circles and thus measure right-ascensions or time-intervals, and also employs the stars of the zenith, which are also separated by given right-ascensional differences.<ref>{{Harvtxt|Pingree|1998}}; {{Harvtxt|Rochberg|2004}}; {{Harvtxt|Evans|1998}}.</ref>

A significant increase in the quality and frequency of Babylonian observations appeared during the reign of [[Nabonassar]] (747–733 BC). The systematic records of ominous phenomena in [[Babylonian astronomical diaries]] that began at this time allowed for the discovery of a repeating 18-year cycle of [[lunar eclipse]]s, for example. The Greek astronomer [[Ptolemy]] later used Nabonassar's reign to fix the beginning of an era, since he felt that the earliest usable observations began at this time.

The last stages in the development of Babylonian astronomy took place during the time of the [[Seleucid Empire]] (323–60 BC). In the 3rd century BC, astronomers began to use "goal-year texts" to predict the motions of the planets. These texts compiled records of past observations to find repeating occurrences of ominous phenomena for each planet. About the same time, or shortly afterwards, astronomers created mathematical models that allowed them to predict these phenomena directly, without consulting records. A notable Babylonian astronomer from this time was [[Seleucus of Seleucia]], who was a supporter of the [[heliocentrism|heliocentric model]].

Babylonian astronomy was the basis for much of what was done in [[Greek astronomy|Greek and Hellenistic astronomy]], in classical [[Indian astronomy]], in Sassanian Iran, in Byzantium, in Syria, in [[Islamic astronomy]], in Central Asia, and in Western Europe.<ref name="dp1998">{{Harvtxt|Pingree|1998}}</ref>

===India===
{{Main|Indian astronomy}}
{{Further|History of science#Indian astronomy}}
{{See also|Hindu astrology}}Astronomy in the Indian subcontinent dates back to the period of [[Indus Valley Civilisation]] during 3rd millennium BC, when it was used to create calendars.<ref name="Bely">{{cite book|url=https://books.google.com/books?id=PbLPel3zRdEC&pg=PA197|title=A Question and Answer Guide to Astronomy|author1=Pierre-Yves Bely|author2=Carol Christian|author3=Jean-René Roy|publisher=Cambridge University Press|year=2010|isbn=978-0-521-18066-5|page=197}}</ref> As the Indus Valley civilization did not leave behind written documents, the oldest extant Indian astronomical text is the [[Vedanga Jyotisha]], dating from the [[Vedic period]].<ref name="Cosmic">{{cite book|chapter-url=https://books.google.com/books?id=PFTGKi8fjvoC&pg=FA25|title=Cosmic Perspectives|last=Subbarayappa|first=B. V.|date=14 September 1989|publisher=Cambridge University Press|isbn=978-0-521-34354-1|editor=Biswas, S. K.|pages=25–40|chapter=Indian astronomy: An historical perspective|editor2=Mallik, D. C. V.|editor3=[[C. V. Vishveshwara|Vishveshwara, C. V.]]}}</ref> The Vedanga Jyotisha is attributed to Lagadha and has an internal date of approximately 1350&nbsp;BC, and describes rules for tracking the motions of the Sun and the Moon for the purposes of ritual. It is available in two recensions, one belonging to the Rig Veda, and the other to the Yajur Veda. According to the Vedanga Jyotisha, in a ''yuga'' or "era", there are 5 solar years, 67 lunar sidereal cycles, 1,830 days, 1,835 sidereal days, and 62 synodic months. During the sixth century, astronomy was influenced by the Greek and Byzantine astronomical traditions.<ref name="Bely" /><ref>Neugebauer, O. (1952) Tamil Astronomy: A Study in the History of Astronomy in India. Osiris, 10:252–276.</ref><ref>{{Cite journal |last=Kak |first=Subhash |date=1995 |title=The Astronomy of the Age of Geometric Altars |journal=Quarterly Journal of the Royal Astronomical Society |volume=36 |pages=385–395|bibcode=1995QJRAS..36..385K}}</ref>

[[Aryabhata]] (476–550), in his magnum opus ''[[Aryabhatiya]]'' (499), propounded a computational system based on a planetary model in which the Earth was taken to be [[Earth's rotation|spinning on its axis]] and the periods of the planets were given with respect to the Sun. He accurately calculated many astronomical constants, such as the periods of the planets, times of the [[solar eclipse|solar]] and [[lunar eclipse|lunar]] [[eclipse]]s, and the instantaneous motion of the Moon.<ref name="Joseph">{{harvtxt|Joseph|2000}}.</ref><ref>Thurston, H, ''Early Astronomy.'' Springer, 1994, p. 178–188.</ref>{{Page needed|date=September 2010}} Early followers of Aryabhata's model included [[Varāhamihira]], [[Brahmagupta]], and [[Bhāskara II]].

Astronomy was advanced during the [[Shunga Empire]], and many [[star catalogue]]s were produced during this time. The Shunga period is known{{According to whom|date=May 2017}} as the "Golden age of astronomy in India".
It saw the development of calculations for the motions and places of various planets, their rising and setting, [[Astronomical conjunction|conjunctions]], and the calculation of eclipses.

By the sixth century, Indian astronomers believed that comets were celestial bodies that re-appeared periodically. This was the view expressed in the sixth century by the astronomers [[Varahamihira]] and Bhadrabahu. The tenth-century astronomer [[Bhattotpala]] listed the names and estimated periods of certain comets, but it is not known how these figures were calculated or how accurate they were.<ref>{{cite book|url=https://books.google.com/books?id=ILBuYcGASxcC&pg=PA293|title=Exploring Ancient Skies: A Survey of Ancient and Cultural Astronomy|last1=Kelley|first1=David H.|last2=Milone|first2=Eugene F.|date=2011|page=293|publisher=Springer |isbn=9781441976246}}</ref>

===Greece and Hellenistic world===
{{Main|Ancient Greek astronomy}}
[[File:Antikythera Fragment A (Front).webp|thumb|The [[Antikythera Mechanism]] was an [[analog computer]] dating from between 200 BC to 80&nbsp;BC designed to calculate the positions of astronomical objects.]]

The [[Ancient Greeks]] developed astronomy, which they treated as a branch of mathematics, to a highly sophisticated level. The first geometrical, three-dimensional models to explain the apparent motion of the planets were developed in the 4th century BC by [[Eudoxus of Cnidus]] and [[Callippus of Cyzicus]]. Their models were based on nested homocentric spheres centered upon the Earth. Their younger contemporary [[Heraclides Ponticus]] proposed that the Earth rotates around its axis.

A different approach to celestial phenomena was taken by natural philosophers such as [[Plato]] and [[Aristotle]]. They were less concerned with developing mathematical predictive models than with developing an explanation of the reasons for the motions of the Cosmos. In his ''Timaeus'', Plato described the universe as a spherical body divided into circles carrying the planets and governed according to harmonic intervals by a [[Anima mundi|world soul]].<ref>Plato, ''Timaeus,'' 33B-36D</ref> Aristotle, drawing on the mathematical model of Eudoxus, proposed that the universe was made of a complex system of concentric [[Celestial spheres|spheres]], whose circular motions combined to carry the planets around the Earth.<ref>Aristotle, ''Metaphysics,'' 1072a18-1074a32</ref> This basic cosmological model prevailed, in various forms, until the 16th century.

In the 3rd century BC [[Aristarchus of Samos]] was the first to suggest a [[heliocentric]] system, although only fragmentary descriptions of his idea survive.<ref>{{harvtxt|Pedersen|1993|pp=55–6}}.</ref> [[Eratosthenes]] estimated the [[circumference of the Earth]] with great accuracy (see also: [[history of geodesy]]).<ref>{{harvtxt|Pedersen|1993|pp=45–7}}.</ref>

Greek geometrical astronomy developed away from the model of concentric spheres to employ more complex models in which an [[deferent|eccentric]] circle would carry around a smaller circle, called an [[epicycle]] which in turn carried around a planet. The first such model is attributed to [[Apollonius of Perga]] and further developments in it were carried out in the 2nd century BC by [[Hipparchus|Hipparchus of Nicea]]. Hipparchus made a number of other contributions, including the first measurement of [[precession]] and the compilation of the first star catalog in which he proposed our modern system of [[apparent magnitude]]s.

The [[Antikythera mechanism]], an [[Ancient Greece|ancient Greek]] astronomical observational device for calculating the movements of the Sun and the Moon, possibly the planets, dates from about 150–100 BC, and was the first ancestor of an astronomical [[computer]]. It was discovered in an ancient shipwreck off the Greek island of [[Antikythera]], between [[Kythera]] and [[Crete]]. The device became famous for its use of a [[differential gear]], previously believed to have been invented in the 16th century, and the miniaturization and complexity of its parts, comparable to a clock made in the 18th century. The original mechanism is displayed in the Bronze collection of the [[National Archaeological Museum of Athens]], accompanied by a replica.

===Ptolemaic system===
{{main article|Ptolemaic system}}

Depending on the historian's viewpoint, the acme or corruption{{citation needed|date=August 2023}}{{dubious|date=August 2023}} of Classical physical astronomy is seen with [[Ptolemy]], a Greco-Roman astronomer from Alexandria of Egypt, who wrote the classic comprehensive presentation of geocentric astronomy, the ''Megale Syntaxis'' (Great Synthesis), better known by its Arabic title ''[[Almagest]]'', which had a lasting effect on astronomy up to the [[Renaissance]]. In his ''Planetary Hypotheses'', Ptolemy ventured into the realm of cosmology, developing a physical model of his geometric system, in a universe many times smaller than the more realistic conception of [[Aristarchus of Samos]] four centuries earlier.

===Egypt===
{{Main|Egyptian astronomy}}
[[File:Senenmut-Grab.JPG|thumb|Segment of the [[astronomical ceiling of Senenmut's Tomb]] (circa 1479–1458 BC), depicting constellations, protective deities, and twenty-four segmented wheels for the hours of the day and the months of the year]]

The precise orientation of the [[Egyptian pyramids]] affords a lasting demonstration of the high degree of technical skill in watching the heavens attained in the 3rd millennium BC. It has been shown the Pyramids were aligned towards the [[pole star]], which, because of the [[precession of the equinoxes]], was at that time [[Thuban]], a faint star in the constellation of [[Draco (constellation)|Draco]].<ref>Ruggles, C.L.N. (2005), ''Ancient Astronomy'', pages 354–355. ABC-Clio. {{ISBN|1-85109-477-6}}.</ref> Evaluation of the site of the temple of [[Amun-Re]] at [[Karnak]], taking into account the change over time of the [[obliquity of the ecliptic]], has shown that the Great Temple was aligned on the rising of the [[winter solstice|midwinter]] Sun.<ref>Krupp, E.C. (1988). "Light in the Temples", in C.L.N. Ruggles: Records in Stone: Papers in Memory of Alexander Thom. CUP, 473–499. {{ISBN|0-521-33381-4}}.</ref> The length of the corridor down which sunlight would travel would have limited illumination at other times of the year. The Egyptians also found the position of Sirius (the dog star), who they believed was Anubis, their jackal-headed god, moving through the heavens. Its position was critical to their civilisation as when it rose heliacal in the east before sunrise it foretold the flooding of the Nile. It is also the origin of the phrase "dog days of summer".<ref>{{Cite web |title=dog days {{!}} Etymology, origin and meaning of phrase dog days by etymonline |url=https://www.etymonline.com/word/dog%20days |access-date=2023-11-01 |website=www.etymonline.com}}</ref>

Astronomy played a considerable part in [[religious]] matters for fixing the dates of festivals and determining the hours of the [[night]]. The titles of several temple books are preserved recording the movements and phases of the [[Sun]], [[Moon]], and [[star]]s. The rising of [[Sirius]] ([[Egyptian language|Egyptian]]: Sopdet, [[Ancient Greek|Greek]]: Sothis) at the beginning of the inundation was a particularly important point to fix in the yearly calendar.

Writing in the [[Roman era]], [[Clement of Alexandria]] gives some idea of the importance of astronomical observations to the sacred rites:
<blockquote>And after the Singer advances the Astrologer (ὡροσκόπος), with a ''horologium'' (ὡρολόγιον) in his hand, and a ''palm'' (φοίνιξ), the symbols of [[ancient Egyptian astronomy|astrology]]. He must know by heart the [[Hermetism|Hermetic]] astrological books, which are four in number. Of these, one is about the arrangement of the fixed stars that are visible; one on the positions of the Sun and Moon and five planets; one on the conjunctions and phases of the Sun and Moon; and one concerns their risings.<ref>Clement of Alexandria, ''Stromata'', vi. 4</ref></blockquote>

The Astrologer's instruments (''horologium'' and ''palm'') are a [[plumb line]] and sighting instrument{{Clarify|date=November 2009}}<!--SEE TALK!-->. They have been identified with two inscribed objects in the [[Egyptian Museum of Berlin|Berlin Museum]]; a short handle from which a plumb line was hung, and a palm branch with a sight-slit in the broader end. The latter was held close to the eye, the former in the other hand, perhaps at arm's length. The "Hermetic" books which Clement refers to are the Egyptian theological texts, which probably have nothing to do with [[Hellenistic]] [[Hermetism]].<ref>Neugebauer O, ''Egyptian Planetary Texts'', Transactions, American Philosophical Society, Vol. 32, Part 2, 1942, Page 237.</ref>

From the tables of stars on the ceiling of the tombs of [[Rameses VI|Rameses&nbsp;VI]] and [[Rameses IX|Rameses&nbsp;IX]] it seems that for fixing the hours of the night a man seated on the ground faced the Astrologer in such a position that the line of observation of the [[pole star]] passed over the middle of his head. On the different days of the year each hour was determined by a fixed star [[culmination|culminating]] or nearly culminating in it, and the position of these stars at the time is given in the tables as in the centre, on the left eye, on the right shoulder, etc. According to the texts, in founding or rebuilding temples the [[north]] axis was determined by the same apparatus, and we may conclude that it was the usual one for astronomical observations. In careful hands it might give results of a high degree of accuracy.

===China===
{{Main|Chinese astronomy}}
{{See also|Book of Silk|Chinese astrology|Timeline of Chinese astronomy}}
[[Image:Su Song Star Map 2.JPG|thumb|[[History of typography in East Asia|Printed]] star map of [[Su Song]] (1020–1101) showing the south polar projection]]

The astronomy of [[East Asia]] began in [[China]]. [[Solar term]] was completed in [[Warring States period]]. The knowledge of Chinese astronomy was introduced into East Asia.

Astronomy in China has a long history. Detailed records of astronomical observations were kept from about the 6th century BC, until the introduction of Western astronomy and the telescope in the 17th century. Chinese astronomers were able to precisely predict eclipses.

Much of early Chinese astronomy was for the purpose of timekeeping. The Chinese used a lunisolar calendar, but because the cycles of the Sun and the Moon are different, astronomers often prepared new calendars and made observations for that purpose.

Astrological divination was also an important part of astronomy. Astronomers took careful note of [[Guest star (astronomy)|"guest stars"]] ({{Lang-zh|c=客星|p=kèxīng|l=guest star}}) which suddenly appeared among the [[fixed star]]s. They were the first to record a supernova, in the Astrological Annals of the Houhanshu in 185&nbsp;AD. Also, the supernova that created the [[Crab Nebula]] in 1054 is an example of a "guest star" observed by Chinese astronomers, although it was not recorded by their European contemporaries. Ancient astronomical records of phenomena like supernovae and comets are sometimes used in modern astronomical studies.

The world's first [[star catalogue]] was made by [[Gan De]], a [[:Category:Chinese astronomers|Chinese astronomer]], in the 4th century BC.

===Mesoamerica===
{{Main|Maya astronomy|Maya calendar|Aztec calendar}}
[[File:Chichen Itza Observatory 2 1.jpg|thumb|"El Caracol" observatory temple at [[Chichen Itza]], [[Mexico]]]]
[[Maya civilization|Maya]] astronomical [[Maya codices|codices]] include detailed tables for calculating [[Lunar phases|phases of the Moon]], the recurrence of eclipses, and the appearance and disappearance of [[Venus]] as morning and [[Venus#Observability|evening star]]. The Maya based their [[Maya calendar|calendrics]] in the carefully calculated cycles of the [[Pleiades]], the [[Sun]], the [[Moon]], [[Venus]], [[Jupiter]], [[Saturn]], [[Mars]], and also they had a precise description of the eclipses as depicted in the [[Dresden Codex]], as well as the ecliptic or zodiac, and the [[Milky Way]] was crucial in their Cosmology.<ref>[http://www.authenticmaya.com/maya_astronomy.htm Maya Astronomy] {{webarchive|url=https://web.archive.org/web/20070606210812/http://www.authenticmaya.com/maya_astronomy.htm|date=2007-06-06}}</ref> A number of important Maya structures are believed to have been oriented toward the extreme risings and settings of Venus. To the ancient Maya, Venus was the patron of war and many recorded battles are believed to have been timed to the motions of this planet. Mars is also mentioned in preserved astronomical codices and early [[Maya mythology|mythology]].<ref>{{harvtxt|Aveni|1980|pp=173–99}}.</ref>

Although the [[Maya calendar]] was not tied to the Sun, [[John E. Teeple|John Teeple]] has proposed that the Maya calculated the [[tropical year|solar year]] to somewhat greater accuracy than the [[Gregorian calendar]].<ref>{{harvtxt|Aveni|1980|pp=170–3}}.</ref> Both astronomy and an intricate numerological scheme for the measurement of time were vitally important components of [[Maya civilization#Religion|Maya religion]].

The Maya believed that the Earth was the center of all things, and that the stars, moons, and planets were gods. They believed that their movements were the gods traveling between the Earth and other celestial destinations. Many key events in Maya culture were timed around celestial events, in the belief that certain gods would be present.<ref>{{Cite web |title=How Does Ancient Mayan Astronomy Portray the Sun, Moon and Planets? |url=https://www.thoughtco.com/ancient-maya-astronomy-2136314 |access-date=2022-03-25 |website=ThoughtCo}}</ref>