Liu Xin , later changed name to Liu Xiu , courtesy name Zijun , was a astronomer and historian during the Xin Dynasty . He was the son of Confucian scholar and an associate of other prominent thinkers such as the philosopher Huan Tan . Liu created a new astronomical system, called "Triple Concordance". He published this system in the year 8 as section of his textbook. In it he provided the following periods:
*The Moon phase period : 29 43/81 days.
*A total of 235 synodic months add up to 19 years.
Therefore his number of days in one year was 365.25016, which is 11 minutes longer than the current value.
Liu created a catalog of 1080 stars, where he used the scale of 6 s. He also calculated periods for planets.
For centuries before the reign of Wang Mang the Chinese had used the value of 3 for their calculation of pi. Between the years 1 and 5, while working for the ''de facto'' head of state Wang Mang, Liu Xin was the first to give a more accurate calculation of pi at 3.154, although the exact method he used to reach this figure is unknown. However, the ancient record of Liu Xin's 'Jia Liang Hu' standard is still preserved in Beijing, which Joseph Needham quotes below with modern references for archaic units :
Although Liu Xin was originally a loyal partisan of Wang Mang, after Wang's troops suffered defeat on July 7, 23 at the Battle of Kunyang, Liu Xin plotted with others to overthrow Wang Mang. The plot was discovered, while all the conspirators committed suicide or were executed.
A on was named in his honor.