After World War II, the new model Mark-IV was created in Oberkochen in 1956, and it was offered for the next ten years. Each star sphere is still organised in 16 star fields. It is illuminated by a halide bulb of 750 W. Aspherical lenses focus the light onto the star field plates. The stars are fabricated in a new photochemical process which make them less sensitive to scratches. Moreover, the brightest 42 stars have a separate projector to avoid thick spots on the dome. Beteigeuze and Antares are coloured reddish, Rigel and Spica have a blue tinge. The Milky Way is introduced and also the most prominent variable stars Mira, Algol and Delta Cephei. Most of these new features are placed on a ring collar at the foot of the star sphere. Another motor arranges the precession.