orrery

A mechanical model of the solar system or parts of it.

A machine so constructed as to represent, by the movements of its parts, the motions and phases of the planets in their orbits. Similar machines are also called planetariums and cosmoscopes.

An apparatus which illustrates, by the revolution of balls moved by wheelwork, the relative size, periodic motions, positions, orbits, etc., of bodies in the solar system.

a clockwork model of the solar system

planetarium consisting of an apparatus that illustrates the relative positions and motions of bodies in the solar system by rotation and revolution of balls moved by wheelwork; sometimes incorporated in a clock