- an apparatus or model representing the planetary system.
- a device that produces a representation of the heavens by the use of a number of moving projectors.
- the building or room in which such a device is housed.
- an instrument for simulating the apparent motions of the sun, moon, and planets against a background of stars by projecting images of these bodies onto the inside of a domed ceiling
- a building in which such an instrument is housed
- a model of the solar system, sometimes mechanized to show the relative motions of the planets
