Celestial globe

Throughout Chinese history, astronomerss have created celestial globes to assist the observation of the stars.

The earliest celestial globe was dated back to 52 BC in the West Han dynasty by the astronomers Geng Shou-chang (耿壽昌) and Luo-xia Hong (落下閎). The first water powered celestial globe was created by Zhang Heng in the East Han dynasty.

Then Li Chun-feng (李淳風) of the Tang dynasty created one in 633 AD with three spherical layers to calibrate multiple aspects of astronomical observations.

In 723 AD, Tang dynasty buddhist monk Yi-xing (一行) and government official Liang Ling-zan (梁令瓚) combined Zhang Heng's water powered celestial globe with an escapement device. The result was allegedly the world's first water powered mechanical clock.