恒こう星せい時じ

noun

sidereal time

Technical term in astronomy; time measured relative to the fixed stars rather than the sun.

• 恒こう星せい時じは、春しゅん分ぶん点てんの時じ角かくで定てい義ぎされる。

  Sidereal time is defined by the hour angle of the vernal equinox.