Chapter 43 Section 3 Debate on whether there is precession

Zu Chongzhi was an accomplished astronomer. When he compiled the Ming Dynasty calendar, he applied the precession difference discovered by Yu Xi not long ago to the calendar calculation for the first time.However, this important innovation was opposed by Dai Faxing, a dignitary at the time. Dai Faxing insisted that there was no precession, denied that the winter solstice point was moving, and accused Zu Chongzhi of introducing precession into the calendar as "falsely adding points and withdrawing the heavenly path" and "fraudulently" The accusation of "reverse the scriptures".Although Zu Chongzhi wrote the "Refutation" and argued hard, he was finally blocked by Dai Faxing's opposition.

Since then, astronomers from the Southern and Northern Dynasties to the early Tang Dynasty dared not discuss precession lightly.Even Li Chunfeng, a famous astronomer in the early Tang Dynasty, opposed the existence of precession.Not only did he criticize the concept of precession, but he wrote "Book of Jin · Tianwenzhi" and "Suishu · Tianwenzhi", etc., which did not mention the important discovery of precession.It was not until the astronomers in the mid-Tang Dynasty that it was formally affirmed, popularized and applied, and the precession value was improved.