In Joseph Needham's third volume of Science and Civilization in China, the drawing for Fig.
159 displays a drawing of Su Song's armillary sphere (as depicted in his 11th century treatise), complete with three 'nests' or layers of mechanically-rotated rings.
It was the earlier Chinese astronomer Li Chun-feng of the Tang Dynasty who in 633 AD created the first armillary sphere with three layers to calibrate multiple aspects of astronomical observation.
Zhang's armillary sphere has often been compared to that of the 13th century monarch Alfonso X of Castile in Islamic-era Spain.
The chief difference was that Alfonso's instrument featured an arrangement for making measurements of the azimuth and altitude, which was present in the Arabic tradition, while Su Song's armillary sphere was duly graduated.
For the drawing of Su's armillary sphere, the listing of components are:
The Outer Nest
meridian circle
horizon circle
outer equator circle
The Middle Nest
solstitial colure circle
ecliptic circle
diurnal motion gear-ring, connecting with the power-drive
The Inner Nest
polar-mounted declination ring or hour-angle circle, with
sighting tube attached to it and strengthened by a
diametral brace
Other Parts
vertical column concealing the transmission shaft
supporting columns in the form of dragons
cross-piece of the base, incorporating water-levels
south polar pivot
north polar pivot
In Joseph Needham's third volume of Science and Civilization in China, the drawing for Fig. 159 displays a drawing of Su Song's armillary sphere (as depicted in his 11th century treatise), complete with three 'nests' or layers of mechanically-rotated rings. It was the earlier Chinese astronomer Li Chun-feng of the Tang Dynasty who in 633 AD created the first armillary sphere with three layers to calibrate multiple aspects of astronomical observation. Zhang's armillary sphere has often been compared to that of the 13th century monarch Alfonso X of Castile in Islamic-era Spain. The chief difference was that Alfonso's instrument featured an arrangement for making measurements of the azimuth and altitude, which was present in the Arabic tradition, while Su Song's armillary sphere was duly graduated. For the drawing of Su's armillary sphere, the listing of components are:
The Outer Nest
meridian circle
horizon circle
outer equator circle
The Middle Nest
solstitial colure circle
ecliptic circle
diurnal motion gear-ring, connecting with the power-drive
The Inner Nest
polar-mounted declination ring or hour-angle circle, with
sighting tube attached to it and strengthened by a
diametral brace
Other Parts
vertical column concealing the transmission shaft
supporting columns in the form of dragons
cross-piece of the base, incorporating water-levels
south polar pivot
north polar pivot
Su Song