Chinese astronomy

thumb|220px|The [[Dunhuang map from the Tang dynasty (schools were distinguished with different colors: white, black, and yellow for the stars of Wu Xian, Gan De, and Shi Shen respectively. The whole set of star maps contain 1,300 stars.]]

Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 xiù) system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE).

Detailed records of astronomical observations began during the Warring States period (fourth century BCE). They flourished during the Han period (202 BCE – 220 CE) and subsequent dynasties with the publication of star catalogues. Chinese astronomy was equatorial, centered on close observation of circumpolar stars, and was based on different principles from those in traditional Western astronomy, where heliacal risings and settings of zodiac constellations formed the basic ecliptic framework. Joseph Needham has described the ancient Chinese as the most persistent and accurate observers of celestial phenomena anywhere in the world before the Islamic astronomers.

Some elements of Indian astronomy reached China with the expansion of Buddhism after the Eastern Han dynasty (25–220 CE), but most incorporation of Indian astronomical thought occurred during the Tang dynasty (618–907 CE), when numerous Indian astronomers took up residence in the Chinese capital Chang'an, and Chinese scholars, such as the Tantric Buddhist monk and mathematician Yi Xing, mastered the Indian system. Islamic astronomers collaborated closely with their Chinese colleagues during the Yuan dynasty, and, after a period of relative decline during the Ming dynasty, astronomy was revitalized under the stimulus of Western cosmology and technology after the Jesuits established their missions. The telescope was introduced from Europe in the seventeenth century. In 1669, the Peking observatory was completely redesigned and refitted under the direction of Ferdinand Verbiest. Today, China continues to be active in the field of astronomy, with many observatories and its own space program.

Early history

Purpose of astronomical observations in the past

thumb|left|Wide view of the [[Crab Nebula.]]

One of the main functions of astronomy was for the purpose of timekeeping. The Chinese used a lunisolar calendar, but as the cycles of the Sun and the Moon are different, leap months had to be inserted regularly. The Chinese calendar was considered to be a symbol of a dynasty. As dynasties would rise and fall, astronomers and astrologers of each period would often prepare a new calendar, making observations for that purpose.

Astrological divination was also an important part of astronomy. Astronomers took note of "guest stars", usually supernovas or comets, which appear among the fixed stars. The supernova which created the Crab Nebula, now known as SN 1054, is an example of an astronomical event observed by Ancient Chinese astronomers. Ancient astronomical records of phenomena like comets and supernovae are sometimes used in modern astronomical studies.

Cosmology

The Chinese developed multiple cosmological models before Western influences changed the field:

Gai Tian ("canopy heaven") – The sky is a hemisphere, the Earth is a disc at the bottom, surrounded by water, which rotates around the North Pole once a day. The Sun traces a circle in the hemisphere, the size of which varies with the seasons. As described in the Zhoubi Suanjing.
Hun Tian ("the entire sky") – Similar to Gai Tian, but the sky is a full sphere. The seasons are explained by the North Pole shifting rather than remaining directly overhead.
Shuen Ye, Xuan Ye, or Suan Ye – The heavens are infinite in extent, the celestial bodies are floating about on their own Very few pieces of information are known about this school of thought.

As lunar mansions have such an ancient origin, the meanings of most of their names have become obscure. Contributing to later confusion, the name of each lunar mansion consists of only one Chinese word, the meaning of which could vary at different times in history. The meanings of the names are still under discussion.

Besides the 28 lunar mansions, most constellations are based on the works of Shi Shen-fu and Gan De, who were astrologists during the period of the Warring States (481–221 BCE) in China. In his Shiji, the Western Han era historian Sima Qian (145–86 BCE) provided a star catalogue that includes 90 constellations. The Eastern Han era polymath scientist and inventor Zhang Heng (78–139 CE) published a star catalogue in 120 CE that features 124 recorded constellations. In the late period of the Ming dynasty, the agricultural scientist and mathematician Xu Guangqi (1562–1633 CE) introduced 23 additional constellations near to the Celestial South Pole, which are based on star catalogues from the Western world introduced by his colleague, the Italian Jesuit Matteo Ricci.

Star catalogues and maps

Star catalogues

In the fourth century BCE, the two Chinese astronomers responsible for the earliest information going into the star catalogues were Shi Shen and Gan De of the Warring States period.

{|class="wikitable"

! Author || Translated name || Chinese catalogue name || Pinyin

| Shi Shen || Shi Shen astronomy || 石申天文 || Shi Shen tianwen

| Ma Xian (馬顯) || Star Manual of the Masters Gan and Shi || 甘石星經 || Gan Shi Xingjing || Despite having the name credited to Shi and Gan, it was lost and later compiled circa 579 CE as an appendix to the Treatise on Astrology of the Kaiyuan Era, and summarized in the book 郡齋讀書志.

| || Book of Jin || 晉書 || Jin shu || In the astronomical chapters of the text The astronomical table of sines by the Indian astronomer and mathematician Aryabhata were also translated into the Kaiyuan Zhanjing.

| || The Great Firmament Star Manual Common to Astrology || 通占大象曆星經 || Tongzhan taxiangli xingjing || This renamed star manual is incorporated in the Taoist book Daozang. The Chinese classic text Star Manual of Master Wu Xian (巫咸星經) and its authorship is still in dispute, because it mentioned names of twelve countries that did not exist in the Shang dynasty, the era in which it was supposed to have been written. Moreover, it was customary in the past for the Chinese to forge works of notable scholars, as this could lead to a possible explanation for the inconsistencies found. Wu Xian is generally mentioned as the astronomer who lived many years before Gan and Shi.

The Han dynasty astronomer and inventor Zhang Heng (78–139 CE) not only catalogued some 2500 different stars, but also recognized more than 100 different constellations. Zhang Heng also published his work Ling Xian, a summary of different astronomical theories in China at the time. In the subsequent period of the Three Kingdoms (220–280 CE), Chen Zhuo (陳卓) combined the work of his predecessors, forming another star catalogue. This time, 283 constellations and 1464 stars were listed. The astronomer Guo Shoujin of the Yuan dynasty (1279–1368 CE) created a new catalogue, which was believed to contain thousands of stars. Unfortunately, many of the documents of that period were destroyed, including that of Shoujin. Imperial Astronomical Instruments (儀象考成) was published in 1757 and contains 3083 stars exactly.

Star maps

thumb|right|230px|A [[star map with a cylindrical projection. Su Song's star maps represent the oldest existent ones in printed form.]]

The Chinese drew many maps of stars in the past centuries. It is debatable as to which counts as the oldest star maps, since pottery and old artifacts can also be considered star maps. One of the oldest existent star maps in printed form is from Su Song's (1020–1101 CE) celestial atlas of 1092 CE, which was included in the horological treatise on his clocktower. The most famous one is perhaps the Dunhuang map found in Dunhuang, Gansu. Uncovered by the British archaeologist Marc Aurel Stein in 1907, the star map was brought to the British Museum in London. The map was drawn on paper and represents the complete sky, with more than 1,350 stars. Although ancient Babylonians and Greeks also observed the sky and catalogued stars, no such complete record of the stars may exist or survive. Hence, this is the oldest chart of the skies at present.

According to recent studies, the map may date the manuscript to as early as the seventh century CE (Tang dynasty). Scholars believe the star map dates from 705 to 710 CE, which is the reign of Emperor Zhongzong of Tang. There are some texts (Monthly Ordinances, 月令) describing the movement of the sun along the sky each month, which was not based on the observation at that time.

Solar and lunar eclipses

Chinese astronomers recorded 1,600 observations of solar and lunar eclipses from 750 BCE. The ancient Chinese astronomer Shi Shen (fl. fourth century BCE) was aware of the relation of the Moon in a solar eclipse, as he provided instructions in his writing to predict them by using the relative positions of the Moon and the Sun. The radiating-influence theory, where the Moon's light was nothing but a reflection of the Sun's, was supported by the mathematician and music theorist Jing Fang (78–37 BCE), yet opposed by the Chinese philosopher Wang Chong (27–97 CE), who made clear in his writing that this theory was nothing new. Jing Fang wrote:

The ancient Greeks had known this as well, since Parmenides and Aristotle supported the theory of the Moon shining because of reflected light.

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The later Song dynasty scientist Shen Kuo (1031–1095 CE) used the models of lunar eclipse and solar eclipse in order to prove that the celestial bodies were round, not flat. This was an extension of the reasoning of Jing Fang and other theorists as early as the Han dynasty. In his Dream Pool Essays of 1088  CE, Shen related a conversation he had with the director of the Astronomical Observatory, who had asked Shen if the shapes of the Sun and the Moon were round like balls or flat like fans. Shen Kuo explained his reasoning for the former:

If they were like balls they would surely obstruct each other when they met. I replied that these celestial bodies were certainly like balls. How do we know this? By the waxing and waning of the moon. The moon itself gives forth no light, but is like a ball of silver; the light is the light of the sun (reflected). When the brightness is first seen, the sun (-light passes almost) alongside, so the side only is illuminated and looks like a crescent. When the sun gradually gets further away, the light shines slanting, and the moon is full, round like a bullet. If half of a sphere is covered with (white) powder and looked at from the side, the covered part will look like a crescent; if looked at from the front, it will appear round. Thus we know that the celestial bodies are spherical.

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Equipment and innovation

Armillary sphere (渾儀)

thumb|right|280px|A method of making observation instruments at the time of the [[Qing dynasty]]

The earliest development of the armillary sphere in China goes back to the 1st century BCE, as they were equipped with a primitive single-ring armillary instrument. This would have allowed them to measure the north polar distance (去極度, the Chinese form of declination) and measurement that gave the position in a hsiu (入宿度, the Chinese form of right ascension).

During the Western Han dynasty (202 BCE–9 CE), additional developments made by the astronomers Luoxia Hong (落下閎), Xianyu Wangren (鮮于妄人), and Geng Shouchang (耿壽昌) advanced the use of the armillary in its early stage of evolution. In 52 BCE, it was the astronomer Geng Shou-chang who introduced the fixed equatorial ring to the armillary sphere.

The astronomical table of sines by the Indian astronomer and mathematician Aryabhata was translated into the Chinese astronomical and mathematical book Treatise on Astrology of the Kaiyuan Era (Kaiyuan Zhanjing), compiled in 718 CE, during the Tang dynasty.

Islamic astronomy in East Asia

thumb|200px|right|Early European drawing of the [[Beijing Ancient Observatory.]]

Islamic influence on Chinese astronomy was first recorded during the Song dynasty, when a Hui Muslim astronomer named Ma Yize introduced the concept of 7 days in a week and made other contributions.

Islamic astronomers were brought to China in order to work on calendar-making and astronomy during the Mongol Empire and the succeeding Yuan dynasty. Kublai Khan brought Iranians to Beijing to construct an observatory and an institution for astronomical studies.

Several Chinese astronomers worked at the Maragheh observatory, founded by Nasir al-Din al-Tusi in 1259 under the patronage of Hulagu Khan in Persia. One of these Chinese astronomers was Fu Mengchi, or Fu Mezhai.

In 1267, the Persian astronomer Jamal ad-Din, who previously worked at Maragha observatory, presented Kublai Khan with seven Persian astronomical instruments, including a terrestrial globe and an armillary sphere, as well as an astronomical almanac, which was later known in China as the Wannian Li ("Ten Thousand Year Calendar" or "Eternal Calendar"). He was known as "Zhama Luding" in China, where, in 1271, While formulating the Shoushili calendar in 1281, Shoujing's work in spherical trigonometry may have also been partially influenced by Islamic mathematics, which was largely accepted at Kublai's court. These possible influences include a pseudo-geometrical method for converting between equatorial and ecliptic coordinates, the systematic use of decimals in the underlying parameters, and the application of cubic interpolation in the calculation of the irregularity in the planetary motions. though the Qing dynasty had officially abandoned the tradition of Chinese-Islamic astronomy in 1659. The Muslim astronomer Yang Guangxian was known for his attacks on the Jesuit's astronomical sciences.

Jesuit activity in China

Early-modern European science was introduced into China by Jesuit priest astronomers as part of their missionary efforts, in the late sixteenth century and early seventeenth century.

The telescope was introduced to China in the early seventeenth century. The telescope was first mentioned in Chinese writing by Manuel Dias the Younger (Yang Manuo), who wrote his Tian Wen Lüe in 1615. In 1626, Johann Adam Schall von Bell (Tang Ruowang) published the Chinese treatise on the telescope known as the Yuan Jing Shuo (The Far-Seeing Optic Glass). The Chongzhen Emperor (1627–1644) of the Ming dynasty acquired the telescope of Johannes Terrentius (or Johann Schreck; Deng Yu-han) in 1634, ten years before the collapse of the Ming dynasty. Thus, the Jesuits initially shared an Earth-centered and largely pre-Copernican astronomy with their Chinese hosts (i.e., the Ptolemaic-Aristotelian views from Hellenistic times). The Chinese often were fundamentally opposed to this as well, since the Chinese had long believed (from the ancient doctrine of Xuan Ye) that the celestial bodies floated in a void of infinite space. There were also Jesuits in China who were in favor of the Copernican theory, such as Nicholas Smogulecki and Wenceslaus Kirwitzer. In contrast, the Copernican view was not accepted in mainstream China until the early nineteenth century, with the Protestant missionaries such as Joseph Edkins, Alex Wylie, and John Fryer. which had been established in the third century BC, and the Muslim Astronomical Bureau (also named Hui-hui ssu-t’ien-chien), which had been previously established by the Mongols. Both sectors worked together, until the Muslim Bureau was absorbed in 1370 by the Traditional Chinese Bureau.

Responsibilities of the Bureau

Some of the roles astronomers played in Ming China were to make calendars, report abnormalities to the emperor, and preside over ceremonies. As calendar makers and people who understand the heavens, the Bureau also decided what days were auspicious and good for different events such as military parades, marriage, construction, and more. However, records indicate that the majority of work the Astronomical Bureaus did was simply recording the movements of the stars and planets.

In regards to the specific jobs each position does, the Chief Officials of the Five Agencies would fix the calendar and the time of the seasons, along with the Calendar Officials and Astronomers. However, the Chief Astronomer observes the positions of the sun, moon, and planets to make notes regarding what might be an abnormality. The Chief Diviner specializes in analyzing the astronomical abnormalities. The Chief Clepsydra Officer looks after the CLepsydra, along with the Clepsydra professor, who then tell the Sunrise Announcer when sunrise and sunset would occur. Astronomy was attractive because it blended the physical world with larger implications. However, astronomy was considered part of the "small dao", a title used to attempt to discourage Confucian scholars from studying subjects that, while interesting at first, could eventually bog them down.

Payment

Within the Bureau, payment was decided upon by rank. As established in the year 1392, the top rank of Director was paid sixteen piculs of rice per month. The Deputy Directors and Chiefs of the Five Agencies were allotted ten piculs per month, the Astronomers received seven piculs, while both the Registrars and Chief Diviners had six-and-a-half piculs. The Chiefs of the Clepsydras received six piculs, and the Calendar Officers and Observers both had five-and-a-half piculs. The lowest payment level went to the Observers of the Sunrise and the Professors of the Clepsydras, at five piculs per month.

Imperial Observatory

The imperial observatory was a platform where the observations were made. It was first located just south of Nanjing, but later moved to Jiming Mountain city. However, in 1402 there was another platform created in the capital of Beijing.

Armillary Sphere (Ming China)

The armillary sphere has three sets of rings that represent the celestial sphere. The first group contains fixed meridian, horizon, and equatorial rings. The second group contains ecliptic, solstitial, and equinoctial rings that turn as a unit. The inner group contains one meridian ring that moves around the celestial pole. These allow the astronomer to set a celestial object within their sights and judge distance.

The Simplified Instrument

The simplified instrument serves a very similar purpose to the armillary sphere but has fewer parts. With only two sets of coordinates, this instrument has a larger range and vision than the armillary spheres.

Clepsydra

The clepsydra, or water clock, was the most prevalent of time-keeping devices for astronomers. The clepsydra was also used as the official state time-keeping device. The Astronomical Bureau used a three-chamber-intake clepsydra, although there is no record of a water clock at Nanjing. It was not until the Bureau moved to Beijing that an official water hall was observed.

Outside perspective

Because of the ideological importance of astronomy regarding politics, and the lack of precision by the instruments, many people believed the observations were false. Other recorded corruption, such as accepting bribery, stealing, and not being punctual, were also experienced. This led to a strict policy of punishment if the astronomers were found to be corrupt. Punishments included such actions as dismissal, deprivation of salary, or even beatings.

References

Citations

Sources

Ho Peng Yoke. “The Astronomical Bureau in Ming China” Journal of Asian History, vol. 3, no. 2, 1969, pp. 137–157. .
Deane, Thatcher E. “Instruments and Observation at the Imperial Astronomical Bureau during the Ming Dynasty.” Osiris, vol. 9, 1994, pp. 126–140. .
Yung Sik Kim, “Confucian Scholars and Specialized Scientific and Technical Knowledge in Traditional China, 1000–1700: A Preliminary Overview,” East Asian Science, Technology, and Society: an International Journal Volume 4.2 (April): 207–228.

External links

The Mathematics of the Chinese Calendary by Helmar Aslaksen
Boundaries Crossing: Western Astronomy in Confucian China, 1600–1800 by Pingyi Chu
Homepage of the National Astronomical Observatories, Chinese Academy of Sciences
Chinese astronomy at the University of Maine
Virtual exhibition about Joseph-Nicolas Delisle and oriental astronomy on the digital library of Paris Observatory