A Zeiss projector is one of a line of planetarium projectors manufactured by the Carl Zeiss Company. Main models include Copernican (1924), Model I (1925), Model II (1926), Model III (1957), Model IV (1957), Model V (1965), Model VI (1968), Spacemaster (1970), Cosmorana (1984), Skymaster ZKP2 (1977), and Skymaster ZKP3 (1993).

The first modern planetarium projectors were designed and built in 1924 by the Zeiss Works of Jena, Germany in 1924. Zeiss projectors are designed to sit in the middle of a dark, dome-covered room and project an accurate image of the stars and other astronomical objects on the dome. They are generally large, complicated, and imposing machines.

The first Zeiss Mark I projector (the first planetarium projector in the world) was installed in the Deutsches Museum in Munich in August, 1923. It possessed a distinctive appearance, with a single sphere of projection lenses supported above a large, angled "planet cage". Marks II through VI were similar in appearance, using two spheres of star projectors separated along a central axis that contained projectors for the planets. Beginning with Mark VII, the central axis was eliminated and the two spheres were merged into a single, egg-shaped projection unit.