中文翻译与英英解释

[line] 【天文学】天球赤道，昼夜平分线。

equinoctial:    adj. 1.【天文学】二分点的；昼夜分线的；昼夜平分时 ...

circle:    n. 1.圆；圆周；圈；环；环状物。 2.圆形场地，马戏 ...

the great circle on the celestial sphere midway between the celestial poles
同义词：celestial equator, equinoctial line, equinoctial,