Lingxian written by Zhang Heng in the Eastern Han Dynasty is an astronomical masterpiece and an immortal masterpiece in the history of world astronomy.
The Classic of Shigan Star in the Spring and Autumn Period and the Warring States Period is the earliest astronomical work in the world, which records the operation of the five stars and their operation rules in detail.
The Dry Elephant Calendar was written by Liu Hong (about 135-2 10) in the 11th year of Jian 'an (AD 206). It has made new progress in the study of lunar movement, and put forward the movement of the perigee (perigee) of the moon for the first time, thus calculating the length of perigee month, and compiling the monthly departure table day by day in perigee month, and putting forward the yellow-white intersection table for the first time.
The Emperor's Calendar was written by Liu Zhuo (544-6 10) in the fourth year of Wendi Renshou (AD 604), but it was not published. Considering the uneven apparent motion of the sun and the moon, the emperor's calendar calculated the three times when the sun and the moon met, and established the equal interval quadratic difference interpolation method. 1. In order to obtain the crescent correction value at any time, a quadratic interpolation method at any interval is also created.