Yuan Astronomical Instruments (Guo Shoujing System)

Timeline

1. 1331–1335Dadu Astronomical Bureau · DaduAfter Guo Shoujing's death, the abridged armilla, gnomon, and other instruments he cast remained at the Dadu Astronomical Bureau, where officials of the Astrology Office led mathematicians in continued observation of sun shadows and stellar positions to verify the Shoushi calendar; the abridged armilla separated equatorial and ecliptic observations with a double-ring structure, while the gnomon with its shadow-definer measured solstice shadow lengths for the calendar.
2. 1336–1340Kaifeng observatory · HenanThe Yuan set up 27 astronomical observation stations nationwide, with Kaifeng, Hangzhou, and elsewhere replicating the abridged armilla and sun-viewing instrument; the latter observed the sun via hemispherical projection to directly record solar eclipses, and stations reported results under unified calendrical procedures supporting the dynasty's calendar promulgation and agricultural timing; though created in Guo Shoujing's era, these instruments continued daily operation within the administrative system.