Unlike conventional planetariums, which are limited to showing the night sky as it appears from various points on the surface of the Earth at various dates, the STS could show the sky as it would appear from anywhere within about 100 astronomical units of Earth (about three times the radius of Pluto's orbit). A joystick even allowed the operator to "fly" the theater through space, showing the resulting apparent movement of planets through the sky, though in practice the planetarium presentations were always pre-programmed.