Chinese astronomy has a history that spans over several millennia. And just like how the ancient Indians, Persians, and the Greeks have been instrumental in the development of astronomy across the world, the Chinese have also made numerous significant contributions in the field.
The first proof of astronomy being practiced by the Chinese comes from a tomb dated around 4000 B.C. that contains inscriptions that showed astronomical symbols. It is believed that the Chinese used circumpolar stars as a tool to chart the heavens.
A more solid proof comes from a 433 B.C. lacquered box that showed the name of all 28 mansions of the sky as described by the early Chinese astronomers. It is also believed that the Chinese had been using a 60-year time cycle, comprised of 10 stems and 12 branches, from as early as 2600 B.C.
The major purpose of the early astronomers was to track time. They also had to predict dates when a lunar eclipse would take place, failing which they would have been beheaded by the orders of the emperor. In addition, the astronomers were also expected to announce each month’s first day. As centuries passed, Chinese astronomers started moving away from such simplistic pursuits and instead began exploring a bit more about the universe.
Tang and Song dynasties
Chinese astronomy flourished under the Tang and Song dynasties. It was during the Tang period that Chinese astronomers calculated the year to contain about 365 days. This is eerily close to modern calculations, which only show a deviation of about a minute from this figure. The calculation was also used as the basis of one of the most popular and accurate lunisolar calendars of that time, the Daming Calendar.
Meanwhile, the Song Dynasty (A.D. 960 to A.D. 1279) is well characterized by the building of a large number of observatories, the most famous among them being a planetarium that boasted of 28 constellations and more than 1,400 stars.
Some of the most notable ancient Chinese astronomers include the likes of Gan De, Shi Shen, Shen Kuo, and Guo Shoujing. Gan De is estimated to have lived in the 4th century B.C. He is the first person in human history to have compiled a star catalog. In fact, it easily precedes the catalogs created by Hipparchus from Greece by a couple of centuries. It is said that Gan De completed the star catalog together with his contemporary Shi Shen. He is also credited with having been the first person to have observed sunspot activity.
Meanwhile, Shen Kuo (1031-1095), a Song Dynasty statesman, discovered true north using magnetic needles. This essentially made compasses highly accurate for navigation. Europe had to wait another 400 years until the concept of “true north” was discovered for use in navigation. Another major achievement has to be credited to Guo Shoujing (1231-1316), who was able to use a custom sundial to calculate a year’s length to within 30 seconds.
Chinese astronomy also owes a lot to outside influences, specifically India, Persia, and later Europe. The Indian influence started with the arrival of Buddhism. And during the Tang Dynasty, Indian astronomy made huge inroads into Chinese minds. In fact, the director of the dynasty’s national astronomical observatory at one time was an Indian named Gautama Siddha. The works of Indian mathematician and astronomer Aryabhata were also translated into Chinese during this period.
The Persian influence in Chinese astronomy is also strong. In fact, Genghis Khan’s scholar, Yelu Chucai, visited Persia in 1210 to study their calendar, which was later used in the Mongol Empire. Kublai Khan brought Persian astronomers to Beijing in order to set up an education center for astronomy, and also to get an observatory constructed.
As the West began to explore the seas in the 16th century, it came into contact with China and started influencing the astronomical theories prevalent in the country. A big role was played by Jesuit missionaries, who even though they did not want to, eventually leaked European astronomical knowledge of Galileo, Copernicus, and Tycho Brahe into China.
Chinese astronomers have also built several new instruments that contributed significantly to the understanding of astronomy. The first among these is the Armillary Sphere, which is believed to have been in use in China from at least 1 B.C. Later additions to the sphere include the Fixed Equatorial Ring by Geng Shou and the horizon and median rings by Zhang Heng.
Another instrument developed in about A.D. 1276 by Guo Shoujing is the Abridged Armilla, which turned out to be more useful and easier to use than the traditional Armillary Sphere available during that period. Zhang Heng is also known to have created the hydraulic version of the Armillary Sphere.