sidereal
adj. 星的,根据恒星测定的
1. of or relating to the stars or constellations;
2. (of divisions of time) determined by daily motion of the stars;
The sidereal year is not used to construct a calendar.
恒星年不用于编制年历.
Tropical year, and sidereal year are two different concepts.
回归年与恒星年是不同的两个概念.