Ancient Observations of Celestial Phenomena for Time Service

This chapter explores ancient Chinese celestial observations for timekeeping, focusing on celestial coordinate systems, precession, and the Big Dipper's role. It discusses the horizontal, ecliptic, and equatorial coordinate systems, with the equatorial system being pivotal. The discovery of precession by Yu Xi in the Eastern Jin Dynasty is highlighted, alongside Neolithic beliefs linking the Big Dipper to the celestial pole. Archeological finds, like Liangzhu jade artifacts and Hemudu wooden models, reveal early astronomical practices. The origin of the Chinese lunisolar calendar is examined, including solstice/equinox observations and the four-directional winds in Shang oracle bone inscriptions. The chapter integrates astronomical theory with archeological evidence, illustrating how celestial observations shaped timekeeping and cosmological thought in ancient China.