As one of the four advanced natural science subjects in ancient China, astronomy, with the innovative calendars and surprising inventions, played an important role in the world's history of astronomical development.
Since the ancient Chinese believed that the perceived movements of the stars were closely related to the destiny of the country and its rulers, for thousands of years they recorded their movements with great attention. From the 16th century BC to the end of the 19th century AD, almost every dynasty appointed officials charged with the sole task of observing and recording the changes in the heavens. Such observations and records have left a rich astronomical legacy.
The first record of a solar prominence has been found in a tortoise shell inscription, which describes "three suddenly bursting fires eating a chunk of the sun". According to statistics, sunspots occur in a cycle every 11.33 years on average, which is in conformity with ancient Chinese documents and once again testifies to the fact that records of sunspots made by ancient Chinese people are a very valuable astronomical legacy.
Yi Xing (683-727), a monk of the Tang Dynasty, led a large-scale project to identify the locations of the major stars, and, based on the results, concluded that the length of a degree of the meridian line was 351.27 li by Tang measurement, which meant 123.7 km. This was the first measurement of the meridian ever done in the world.
Astronomical studies made impressive headway during the Song Dynasty (960-1279). During this period, five large-scale observations of the sky were undertaken, resulting in star maps. The stone planisphere kept in Suzhou today was first drawn during the reign of Emperor Yuanfeng (1078-85) and then committed to stone in 1247 by Wang Zhiyuan of the Southern Song Dynasty. On the map are 1,434 stars, the ecliptic, the equator, the Milky Way and the twenty-eight constellations. The lower part of the planisphere is occupied by explanations totaling 209 characters, which constitute a concise introduction to the astronomical knowledge man had grasped by that time. This is China's earliest and most complete star map still extant.
Shen Kuo of the Northern Song Dynasty, left behind a great store of notes and research findings in the fields of geography, geology, astronomy and mathematics. His work Dream Stream Essays contains early discussions of the compassand movable type printing. This book is of great value for the study of the history of science.
Other scientist, such as Guo Shoujing (1231-1316), a noted scientist of the Yuan Dynasty, made major improvements to the sundial. Guo Shoujing made great contributions in the areas of astronomy, the calendar and water conservation.
