Chinese astronomy differed from that of the Western world in two important respects: (a) it was polar and equatorial rather than planetary and ecliptic, (b) it was an activity of the bureaucratic state rather than of priests or independent scholars. Both features had advantages and disadvantages; the first led to the mechanization of celestial models long before the West, but deferred recognition of equinoctial precession till later. The second ensured remarkable sets of celestial observations antedating most of those recorded elsewhere, but discouraged causal speculation, especially in the absence of Euclidean deductive geometry. In cosmology, China developed three doctrines: (a) the Kai Thien universe, a domical geocentrism not unlike early Babylonian ideas, (b) the Hun Thien universe, essentially the recognition of the primary celestial spherical coordinates, and (c) the Hsuan Yeh system, which accepted the Hun Thien as methodologically necessary but viewed the heavenly bodies as lights of unknown nature floating in infinite empty space. Instrumentation developed early, armillary rings being in use by the end of the -2nd century and the complete armillary sphere by the end of the +1st.