Sidereal Clock; made in 1800 Attributed to James Newton; Sidereal time is a timekeeping system that astronomers use to locate celestial objects. Using sidereal time; it is possible to easily point a telescope to the proper coordinates in the night sky. Briefly; sidereal time is a time scale that is based on Earth's rate of rotation measured relative to the fixed stars; Wikipedia; Applied Arts; Clock; Science and Industry; Astronomy