Sidereal time - Wikipedia
https://en.wikipedia.org/wiki/Sidereal_timeSidereal time is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky. Sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars". … Näytä lisää