Heaven on Earth

How Jena has influenced the history of planetariums

ZEISS Planetarium in Jena (With courtesy of Sternevent GmbH)

The ZEISS Planetarium in Jena opened on 18 July 1926, making it the world's oldest working planetarium. Thanks to its new projection technology from ZEISS, it is also now one of the world's most modern planetariums.

An early idea of creating an artificial night sky was presented in the 17th century in northern Germany. Up to 12 people fit inside a giant, three-meter globe where they could marvel at the gold-plated nails on the ceiling glimmering in candlelight, which recreated the constellations in the night sky.

Erhard Weigel, a scholar in Jena, was probably inspired by this new technology and built a similar system on the roof of the castle in Jena in 1661. The stars were created by holes in the outer wall of a five-meter dome.

In 1913 Oskar von Miller, founder of the Deutsches Museum in Munich, contacted Dr. Walther Bauersfeld at Carl Zeiss in Jena about the construction of a "rotatable star dome."  However, it didn't seem possible to build a large, heavy dome to move with the stars. Instead, Bauersfeld wanted the stars to move independently and designed a device on the basis of optical-mechanical light projection. The first projector from ZEISS incorporated 31 projectors to beam 4500 stars on the inside of the dome. One of the first shows was held in Munich in 1923.

ZEISS in Jena continued to enhance the projector and installed a test projector on the roof of the factory – also making it available for public shows. Almost 80,000 people visited the "Wonder of Jena" from August 1924 to January 1926. This high demand led to the construction of the current ZEISS planetarium.

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