Astronomical coordinate systems provide a mathematical framework used to specify the precise location of celestial objects relative to a reference frame. These systems typically define coordinates using angular measurements, most commonly involving references to an assumed plane, such as the celestial equator or the ecliptic plane. Major systems include the equatorial coordinate system, which utilizes Right Ascension and Declination, defined by the Earth's rotation axis, and the ecliptic system, which aligns with the plane of Earth's orbit around the Sun. The selection of a coordinate system depends on the geometry of the observation and the target object, with projections designed to minimize distortion while accurately mapping angular position across the celestial sphere.