On September 16, 1923, the construction of the planetarium projector for the Deutsches Museum had progressed far enough that it could be used for the first time using all its functions in the Jena factory dome. But ZEISS was reluctant to send the still unfinished projector to Munich. However, Oskar von Miller, founder and director of the Deutsches Museum, pushed for the demonstration in Munich. Still in September 1923, ZEISS delivered the projector and installed it in the dome of the Deutsches Museum. Finally, Walther Bauersfeld himself personally demonstrated the projector, with now well-known success, at the annual meeting of the museum committee on October 21, 1923. This was the first demonstration before a live audience and is considered the birth of the modern planetarium. 

The projector consists of two gear-coupled components, a sphere carrying the projectors for the stars and a "planet cage" for the display of the Sun, Moon and the five naked-eye planets Mercury, Venus, Mars, Jupiter and Saturn. The "planet cage" projectors are arranged in tiers and coupled together by complex gearings in such a way that a motorized drive makes it possible to simulate the annual motion in fast motion, i.e., the change in location of Sun, Moon and planets against the stars over time. The rotation of the entire projector around a second, the polar axis, allows the presentation of the rising and setting of the celestial bodies. The sphere with the fixed star projectors is placed exactly in the center of the projection dome. It also carries projectors for the Milky Way and displays for the names of the most important constellation figures. Also visible in the photo is the counterweight to the planet cage, which serves as a mass balance for smooth diurnal motion. The black cloth prevents stars from being projected below the dome horizon and thus onto the audience. The photo also shows unpainted and open parts that were finished later.