Copy of a 1870 Orrery
An Orrery is a model showing how the planets in the Solar System orbit the around the Sun. Closest to the Sun is Mercury, then Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Pluto discovered in 1930 is not shown on this Orrery.
The planets are positioned by hand to show any given phase - you will notice that the Earth is on a mechanical arm and when rotated shows the Moon orbiting the Earth.