Chapter 2 Section 2 Development and Improvement

The Western Han Dynasty to the Five Dynasties is the period of development and perfection of ancient Chinese astronomy.From the Taichu calendar to the Futian calendar, in addition to the calendar, the Chinese calendar has added many special contents such as solar term, synodic, intercalary, eclipse, and timing. The system is more perfect, the data is more precise, and new observation methods and calculations are constantly invented. method.For example, Jiang Ji during the Northern and Southern Dynasties used the position of the lunar eclipse to accurately calculate the position of the sun.Liu Zhuo of the Sui Dynasty used equidistant quadratic difference interpolation method to deal with the inhomogeneity of the movement of the sun and the moon in the Huangji Calendar.The Dayan calendar of the Tang Dynasty shows that the ancient Chinese calendar has fully matured. It is recorded in "New Tang Book·Li Zhi", which is divided into seven chapters according to the content, and its structure is imitated by later generations of calendars.

After the fall of Hong (honghong) in the Western Han Dynasty, the function of the armillary sphere increased with the increase of the rings. By the time of Li Chunfeng in the Tang Dynasty, he could use an armillary sphere to measure the equatorial coordinates, the ecliptic coordinates and the white track coordinates of celestial bodies at the same time.Astronomical instruments are tools for measuring the data required by the calendar and testing the quality of the calendar. Its improvement has also promoted the progress of astronomical observations. Discoveries such as precession and the unevenness of the sun, moon and planets have been introduced into calendar calculations.In addition to continuously improving the accuracy of star position measurement, astronomical officials also paid special attention to recording the location and time of strange celestial phenomena. In fact, the latter is what the imperial court is more concerned about.This tradition became a major feature of ancient Chinese astronomy.

The three main views of the universe in ancient China originated from the contention of a hundred schools of thought in the Spring and Autumn and Warring States periods.In the more than 1,000 years after the Qin Dynasty, many branches were derived from them. Later, the Huntian Theory, with its advantages in explaining astronomical phenomena, replaced the Gaitian Theory and became the dominant concept.