Liu Zhuo 劉焯 wrote the Huangji Calendar 皇極曆 (Huángjí Lì) during the Sui Dynasty in 600 AD and Xu Ang 徐昂 wrote the Xuanming Calendar 宣明曆 (Xuānmíng Lì) which was used between 822 to 892 during the Tang Dynasty.
Yixing 一行 measured proper stellar motion. Proper stellar motion is when stars which are closer to us move across the sky at a faster rate than do stars that are far away from us. The amount of movement is extremely small. He also published the Dayan Calender (大衍历 Dà Yǎn Lì, 729 AD). Yi Xing also invented an automated rotating armilary sphere to show the movements of the stars across the heavens. His engineering skills were also applied to an automated clock that would strike the hour. All of his mathematics, engineering, and inventive skills were put to use to make predictions about the heavens. Chinese social and political life depended upon astrological prediction and thus support for astronomical observations was constant and competitive. The fact that Yixing was a monk also gained support for other Buddhist temples and stduy centers. Science, religion, and politics were of one piece.
Star maps were created that were used for astronomy, astrology, and for navigation. One of the most famous examples was found in the Dunhuang caves on the Silk Road.
Last update: March 2010
© Marilyn Shea, 2010