雙語科技百科(天文) 第10期:渾儀
The Armillary Sphere
The Armillary Sphere was an astronomic observatory instrument in ancient China. The ancient people believed the heaven was round，just like an egg，with the stars in the sky resembling the round pills beset in the shell and the earth like the yolk. People used the armillary sphere to examine the posi-tion of celestial bodies from the earth.
渾儀是中國古代的一種天文觀測儀器。古人認爲天是圓的，形狀像蛋殼，出現在天上的星星是鑲嵌在蛋殼上的彈丸，地球則是蛋黃。人們使用渾儀在這個蛋黃上測量天體的位置。The armillary sphere’s structure was very simple at the very beginning，with three rings and a metal axis. The outermost ring-meridian ring-was fixed in the north-south direction，the middle ring-equator ring-was parallel to the earth’s e-quatorial plane，and the innermost one-Chijing ring-could revolve around the metal axis. The Chijing ring and the metal axis intersected at two points，with one pointing to the North Pole and the other to the South Pole. An observatory tube was fixed on the Chijing ring and could rotate around the center of the ring.
最初，渾儀的結構很簡單，只有三個圓環和一根金屬軸。最外面的那個圓環固定在正南北方向上，叫做“子午環”;中間固定着的圓環平行於地球赤道面，叫做“赤道環”；最裏面的圓環可以繞金屬軸旋轉，叫做“赤經環”；赤經環與金屬軸相交於兩點，一點指向北天極，另一點指向南天極。
When used for examining the position of stars，the tube was first aimed at a certain star; then the graduation on the equator and Chijing rings was used to pin-point the star’s position in the sky.
在赤經環面上裝着一根望筒，可以繞赤經環中心轉動，用望筒對準某顆星星，然後，根據赤道環和赤經環上的刻度來確定該星在天空中的位置。Later, in order to facilitate the observation of more celestial bodies，such as the sun，the planets，and the moon，more rings were added inside the armillary sphere，making it a multi-purpose astronomic instrument.
後來，古人爲了便於觀測太陽、行星和月球等天體，在渾儀內又添置了幾個圓環，使渾儀成爲多種用途的天文觀測儀器。
