Orrery with armillary bands, 1740-1747.
© Science Museum / Science & Society Picture Library
This large planetary model is thought to have been made by the London instrument maker Thomas Wright. Known as an orrery or planetarium, it is a demonstration model to show the motions of the Earth, Moon and planets around the Sun. This example has a twelve-sided mahogany base with bras armillary bands and six planets (Mercury-Saturn). Such devices became popular during the 17th century, especially after Sir Isaac Newton (1642-1727) published his universal theory of gravity in 1687. To reproduce the motions of the solar system this model employs a hand crank to drive the gear wheels. This particular orrery was originally acquired by Hackney College, London for teaching astronomical principles.