Hamburg Planetarium, Planetarium in Hamburg Stadtpark, Germany

Hamburg Planetarium occupies a former water tower built between 1912 and 1915, about 65 metres tall, in the centre of Stadtpark. Inside, a 23-metre-high cylindrical room beneath the old water tank was divided into two levels; the upper level holds the projection dome, 20.6 metres across, with 253 reclining seats. The Zeiss Universarium Mark IX projector stands on a black framework beneath the dome.

The nearly 65-metre tower was built in 1912–1915 as a water tower and used for that purpose only until 1924. Conversion to a planetarium began in 1929 under architect Hans Loop, who divided a 23-metre-high cylindrical space beneath the water tank into two floors. The first public show took place on 17 April 1930.

The building's name still points to its past as a water tower, and the former reservoir above the Star Hall remains in place. The lower floor holds a library of astronomical and astrological books assembled by Aby Warburg, kept there since the planetarium conversion; the collection is no longer open to the public. The foyer's "Wandelhalle" was painted by Dorothea Maetzel-Johannsen, who died during the work, and Heinrich Groth finished the murals.

Two elevators carry visitors to the Star Hall and the observation deck at the top, while renovated staircases link all floors inside. Those with time before or after shows can walk through the park and view the tower from outside.

The Star Hall's Zeiss Model IX Universarium projector, in use since the 2002/2003 renovation, is the successor to a Model II bought by the city in 1925. Two video projectors add fulldome images via the Digistar 5 system. Above the hall, the old water tank still sits unused inside the tower.