A source of data pertaining to features of various objects, usually astronomical, that depend on time. The ephemeris can be a printed or computer-readable table such as on a compact disk, or it can be a set of numerical data accessible by computer programs. Most ephemerides pertain to positions of celestial objects as seen from any place in the solar system. The term may also apply to other parameters, such as those describing the state of rotation or orientation of a body in space.