Planetariums, museums, and science centers can be found in most major cities around the world. Science centers are an outgrowth of the original planetarium theaters, which, at their inception in the 1930s, were the only places the general public could learn about science in general and astronomy in particular.

The sphere of the Hayden Planetarium is part of the Rose Center for Earth and Science at New York City's American Museum of National History. The planetarium contains the largest and most powerful virtual reality simulator in the world.

A planetarium consists of a hemispherical-domed theater in which a specialized star projector can display the night sky at any time of the year. Central to the experience is the planetarium projector. There are two principle types of star projectors: opto-mechanical and digital.

Traditional Planetarium Projectors

Opto-mechanical planetarium projectors typically have two spheres incorporating...