Chinese astronomy goes back to the year 3000 BCE. Ancient Chinese astronomers were pioneers in the field and were experts at astronomy. We will look at the history of Chinese astronomy and the various dynasties that contributed to the field. We will look at the methods used by the astronomers, as well as the tools developed for astronomical observations and research. We will also include a brief outline of the various contributions by the astronomers of early Chinese astronomy. Different cultures also influenced ancient early Chinese astronomy, and we will see how those influences played a crucial role in the development of early Chinese astronomy.
The Chinese Calendar
Ancient Chinese astronomers were involved with time keeping. It was the main reason why they studied the heavens. The ancient Chinese calendar was a lunisolar calendar. Chinese astronomers devised the calendar based on the cycles of the Moon and the Sun. It was a symbol of dynasties and with every passing dynasty a new calendar was devised. Chinese astronomers divided the calendar into 24 parts. It was based on the longitudes of the Sun and the phases of the Moon. It is said that Emperor Huangdi had invented the calendar in 2637 BCE. Ancient Chinese astronomers had devised a method of naming each year for an animal sign. The cycle was a 12- year cycle commencing with the rat, followed by the ox, the tiger, the rabbit and so on, until the cycle was completed at the end of 12 years, and then started again with the rat. The ancient Chinese also had an additional intercalary thirteenth month. During the warring-states period, the Chinese were using highly advanced astronomy and mathematics for their calendars.
The 28 Mansions
Ancient Chinese astronomers divided the sky into four quarters. The quarters were then divided into seven mansions, giving a total of 28 mansions. These were then used to chart the position of the Moon across the sky. The quarters were each given the name of an animal. The system is similar to the one used in Hindu astronomy.
Early Chinese astronomers were very interested in observing solar eclipses. Accurately predicting a solar eclipse was crucial for an astrologer, as it signified the health and well-being of an Emperor. By around 20 BCE, astrologers knew what caused eclipses, and by around 8 BCE, certain solar eclipses were predicted using the 135-month recurrence period. By around AD 206, Chinese astrologers were using the motions of the Moon to make predictions of solar eclipses. The belief of the ancient Chinese was that each time a solar eclipse occurred, a legendary dragon in the heavens was devouring the Sun. Traditionally, the Chinese would use drums and pots to make loud noises to frighten the dragon.
The Tang Dynasty
Chinese astronomy greatly advanced in the Tang Dynasty in between the third and sixth centuries. One of the astronomers who contributed greatly to the advancement of early Chinese astronomy during this period was Zu Chongzhi. He calculated the length of the year to be 365.24281481 days. He was off by a minute according to modern measurements. Using this figure, he devised the Daming calendar, which was the most accurate calendar of the period. He was also able to predict solar eclipses to a great deal of accuracy. Another important contribution during the period was that by a monk named Yi Xing. Yi Xing was also an astronomer and plotted the length of a degree of the meridian line with a great deal of accuracy. Modern measurements of the meridian line are not too far off from his measurement.
Read Part 2 of this series to find out the what instruments were used by the ancient Chinese astronomers and much more.
Image Credits:Wikimedia Commons/YiXangKaoCheng//Mysid/Paula Santos/Haros
This post is part of the series: Chinese Astronomy
Historically, Chinese astronomers kept track of the stars, the Sun and the Moon for time keeping. They used highly advanced mathematics and constructed elaborated astronomical instruments. We will peer into the workings of early Chinese astronomy and what cultures influenced it the most.