Yi Xing, born Zhang Sui, was a Chinese astronomer, Buddhist monk, inventor, mathematician, mechanical engineer, and philosopher during the Tang dynasty. His astronomical celestial globe featured a liquid-driven escapement, the first in a long tradition of Chinese astronomical clockworks.
Painting of Yi Xing from the Shingon Hassozō, a series of scrolls depicting the first eight patriarchs of the Shingon school of Buddhism. Japan, Kamakura Period (13th-14th century)
Memorial Pagoda of Monk Yi Xing
An armillary sphere is a model of objects in the sky, consisting of a spherical framework of rings, centered on Earth or the Sun, that represent lines of celestial longitude and latitude and other astronomically important features, such as the ecliptic. As such, it differs from a celestial globe, which is a smooth sphere whose principal purpose is to map the constellations. It was invented separately, in ancient China possibly as early as the 4th century BC and ancient Greece during the 3rd century BC, with later uses in the Islamic world and Medieval Europe.
Jost Bürgi and Antonius Eisenhoit: Armillary sphere with astronomical clock, made in 1585 in Kassel, now at Nordiska Museet in Stockholm
Chinese Armillary sphere at Beijing Capital International Airport 紫薇辰恆 Ziwei Chenheng Aug-2010
The original diagram of Chinese scientist Su Song's book of 1092 showing the inner workings of his clocktower; a mechanically rotated armillary sphere crowns the top.
Armillary sphere at Beijing Ancient Observatory, replica of an original from the Ming dynasty