The Zeiss-Planetarium opened in 1964 and is one of the oldest and largest public planetariums in Germany. It seats 220 under a 20-metre dome and runs an ambitious program of astronomy shows alongside occasional concerts and special events. The building sits in the Stadtpark, a pleasant green space north of the city centre that is worth a walk in good weather.
Shows are mostly in German, but the visual content is largely self-explanatory. Check the online program in advance — popular shows sell out.