Zeiss Planetarium Jena

The Zeiss Planetarium Jena, opened in 1926, goes back to an idea by Oskar von Miller and was realized with the Carl Zeiss company, which developed the first planetarium projector. After the Second World War, it remained as the world's oldest large planetarium still in existence.Between 1983 and 1985, the planetarium was extensively modernized and structurally expanded, with new projection and sound systems being continuously developed. The technical evolution is reflected in four generations of star projectors, including the "Cosmorama", which now stands as a monument in the Goethe Gallery.Today you can attend a wide variety of events here. You can find suggestions and further information here: planetarium-jena.de.

The development of the planetarium is based on an idea by Oskar von Miller, the founder of the Deutsches Museum in Munich, who in 1912 envisaged the construction of a Ptolemaic planetarium in the style of a walk-in celestial globe with a mechanical device to display the planetary orbits in his institution. In 1913, he turned to the Carl Zeiss company in Jena to implement it. Since the original project proved to be technically too complex and almost impossible to implement, Walther Bauersfeld designed the basic form for a planetarium device based on opto-mechanical light projection at the beginning of 1919. This was installed in Munich in 1924 as Model I. (Wikipedia)

One of the biggest attractions in Jena is the planetarium next to the botanical garden. Inaugurated in 1926, it is the oldest of its construction today. The engineers Bauersfeld and Dischinger used the so-called shell construction for the first time in the construction of the dome, which represented a significant structural innovation.
Source (entdecke-jena.de/jena/sehenswuerdheiten.htm)