Chinese Astronomy

Despite China’s enormous extent and local diversity, its literate elite, because of their classical educations, shared not only a language but values and patterns of thought. Among these values was overwhelming prestige for the civil service. One generation of talented astronomers after another sought the only employer ready to provide large, long-term investment in scientific research and development. The government supported large-scale astronomical projects, from the 2nd century BC on, because of the ideology that justified its power. It claimed that the imperial house was chosen by Heaven to shape society in its image. The monarch’s personal virtue and charisma, not his managerial skills, kept him in touch with the cosmic order and enabled him to keep the state in harmony with it. This doctrine included the notion of the Mandate of Heaven. Heaven chose an exceptionally virtuous family to rule. When eventually its descendants no longer maintained that virtue, Heaven transferred the mandate to a worthier family. The conquest that ended a dynasty and began a new one was thus not a crime—if it succeeded.

As a result, the imperial court included an amply staffed Bureau of Astronomy. Its responsibilities for ASTROLOGY and mathematical astronomy were intimately related. Its officials scrutinized the sky for omens, recorded them, determined their meaning from the Bureau’s archives and reported them so that the emperor and his officials could determine how to respond.

The emperor symbolically expressed his control over time as well as space by issuing the annual CALENDAR (actually an ephemeris or almanac that included eclipses and planetary phenomena). He expected the Bureau to incorporate in it the most accurate predictions possible, particularly those of eclipses. As a result of this ongoing state sponsorship, the published historical record offers unbroken, dated records of most important celestial phenomena, and detailed accounts of the evolving methods used to make EPHEMERIDES, for more than two millennia.

Chinese degree measurement was not derived from the Babylonian sexagesimal system. It was based on the du, originally a measure of time intervals between meridian transits, but after about AD 180 redefined as the distance of one day’s mean solar travel.

The time of observations was generally measured by water clocks, of which several examples survive from the last two centuries BC.

Since China was the predominant culture in East Asia, the institutions and methods of its official astronomy provided a foundation for counterparts (always with local character)in Korea, Japan and Vietnam. The desire for accurate prediction of solar eclipses motivated Chinese to hire experts in the geometric methods of the Greek tradition. They employed Indians from 665 on, Muslims during the Mongol occupation (1279–1367) and Jesuit missionaries in the 17th and 18th centuries. The latter, in fact, by offering the Manchu invaders their skills at casting cannon and computing the mandatory imperial ephemerides, took control of the Astronomical Bureau.

All of the great historical civilizations have exchanged ideas and artifacts since the New Stone Age. China was so isolated from Europe, the Middle East and India that
outside scientific influence remained controllable until the mid-19th century. It remained a centrally ruled empire larger than all of Europe for more than 2000 yr. Even in brief periods of division, the continuity of its high culture, unlike that of Europe for much of the Middle Ages, was never interrupted.