tiān / qiú / chì / dào / shì / tiān / qiú / shàng / yǔ / dì / qiú / chì / dào / duì / yìng / de / dà / yuán

天球赤道是天球上与地球赤道对应的大圆。

The celestial equator is the great circle on the celestial sphere corresponding to Earth's equator.