Caption:
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