A system for specifying the position of an object relative to two or three mutually perpendicular axes from some specified origin. The axes are identified as x, y, and (where a third axis is used) z. Cartesian coordinates are rectangular coordinates. In astronomy, rectangular coordinates are sometimes used for Solar System objects, with the length of each axis given in astronomical units. They are usually heliocentric or geocentric in origin, but other points of origin can be used.
Subjects: Astronomy and Astrophysics.