Early Predecessors

The institutional management of astronomical observation and calendrical computation by the Chinese state has ancient roots. During the Zhou dynasty (1046–256 BCE), officials responsible for astronomical records and timekeeping were attached to the royal court, reflecting the early association between celestial observation and state governance.[5] The Zhouli (Rites of Zhou), a classical text describing idealised Zhou-era government, specifies officials tasked with observing the stars, maintaining the calendar, and advising the ruler on the significance of celestial phenomena.

During the Han dynasty (206 BCE – 220 CE), the office of Taishiling (太史令, Grand Historian or Grand Astrologer) served as the principal court position responsible for astronomical observation, calendar maintenance, and the recording of celestial omens. The most famous holder of this office was Sima Qian (c. 145–c. 86 BCE), author of the Shiji (Records of the Grand Historian), which includes the Tianguan Shu (天官書, "Treatise on the Celestial Offices"), a systematic account of celestial phenomena and their astrological significance. The Han court's astronomical apparatus represented a significant institutionalisation of celestial observation, including the development of armillary spheres and other observational instruments.

The institution underwent various reorganisations and name changes across dynasties. During the Sui dynasty (581–618) and Tang dynasty (618–907), the astronomical bureau was known by several names, including the Taishiju (太史局, Bureau of the Grand Historian) and the Taishijian (太史監, Directorate of the Grand Historian).[4] The Tang bureau was responsible for astronomical observation, the production and revision of the official calendar, the prediction of eclipses, the selection of auspicious dates for court ceremonies and construction, and the interpretation of unusual celestial events such as comets, novae, and meteor showers.