Zeiss-Planetarium Jena

The Zeiss Planetarium in Jena has been in operation for more than 90 years, making it the oldest continuously operating projection planetarium in the world. Its opening on 18 July 1926 was revolutionary in many respects – for the natural sciences and technology, cultural theory and media history – and not in the least for its architecture. The Jena planetarium was a completely new building type. Its thin-walled dome, which Zeiss engineer Walther Bauersfeld developed together with structural engineer Franz Dischinger, represented a milestone in the history of building construction.

As early as 1913, Oskar von Miller, the founder of the Deutsches Museum in Munich, approached the optics manufacturing firm Carl Zeiss in Jena with the idea of a “Himmelsschau”, a celestial show. It was not until another 13 years later that the dome construction needed for it was completed. Bauersfeld designed it along with the electromechanical projector. In 1924, the Zeiss company initially erected a temporary planetarium on the roof of one of their factory buildings, which attracted nearly 80,000 fascinated visitors. The star projector went into mass production, and within two years, the permanent Zeiss Planetarium opened in Jena as an institution for public education. It was closely followed by three more planetariums in Germany. The global era of large planetariums had begun.

Adolf Meyer, Walter Gropius’s right-hand man at the Bauhaus, had also sought to build the planetarium. Instead of choosing his design in the modern style of the New Architecture, the Zeiss optics company chose a less contentious neoclassical design by the Jena architects Johannes Schreiter and Hans Schlag.

The lightweight dome of the planetarium – its diameter is 25 metres – was pioneering for modern shell construction. To build the projection screen, a wafer-thin dome shell was created by spraying wet concrete, also known as shotcrete, onto mesh. This new technique opened up entirely new possibilities for the construction of large halls and other column-free geometric structures.

The planetarium in Jena has been repeatedly expanded since the 1980s. Today, visitors can experience a “star theatre” that employs the latest computer-controlled technologies. The dome roof itself was also extensively refurbished and, since 2012, once again boasts its original green colour. [KM/DK]