An orrery is a mechanical device that illustrates the relative positions and motions of the planets and moons in the Solar System in a heliocentric model. Though the Greeks had working planetaria, the first orrery that was a planetarium of the modern era was invented by George Graham (July 7, 1673 - November 20, 1751) under the patronage of Charles Boyle, 4th Earl of Orrery. They are typically driven by a clockwork mechanism, employing a hand crank to drive the gear wheels, with a globe representing the Sun at the center, and with a planet at the end of each of the arms. This model is thought to have been made by the London instrument maker Thomas Wright (16861748).