sidereal
adj. 星的,根據恆星測定的
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.
恆星年不用於編制年曆.
Tropical year, and sidereal year are two different concepts.
迴歸年與恆星年是不同的兩個概念.