Small clockwork or hand-cranked model of the planetary system - a popular astronomical demonstrational apparatus or educational demonstrator during the 18th and 19th centuries. An orrery might complement an astrolabe or a pair of celestial and terrestrial globes in a library or schoolroom.
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
An orrery is a mechanical device that illustrates the relative positions and motions of the planets and moons in the solar system in heliocentric model. They are typically driven by a large clockwork mechanism with a globe representing the Sun at the centre, and with a planet at the end of each of the arms.