The armillary sphere is an instrument for measuring the position of celestial bodies. Although no data about the first armillary sphere has been kept till now, according to astronomical observation records from the book Shi Shi Star Chart and silk manuscripts unearthed from the Han Tomb of Mawangdui in Changsha, the first armillary sphere in China emerged between the early Warring States Period in the fourth century B.C. to the first century B.C. Since the Han Dynasty, the armillary sphere had been produced by every dynasty.

Here shows the armillary sphere created by Su Song in the Northern Song Dynasty. The original object was 4.11 meters high and weighed about 15 tons. It is applied on the Water-driven Astronomical Clock Tower, with its large gear wheel engaging with the axle gear on top of the “celestial pillar”. Under the driving force by waterpower from the clepsydra, it can automatically follow the motions of celestial bodies and conduct observation. The armillary sphere is well-known in the world for its scientific conformation, accurate observation and elegant design.