The Mannheim Observatory was a tower observatory built between 1772 and 1774 in Mannheim, Germany, which remained in operation until 1880.

On New Years Day 1771 the Jesuit Father Christian Mayer presented a memorandum on the construction of an observatory to the Mannheim Court. In 1772 the Palatinate Elector - Karl Theodor, who was a prince of the Age of Enlightenment and a patron of sciences - charged the Court Chamberlain with the construction of the observatory. In the same year the foundation stone of the tower was laid next to Schloss Mannheim, in the vicinity of the Jesuit College. In the following years Mayer acquired numerous instruments and with the help of books delivered from the Electoral Library made the Mannheim Observatory into an internationally known research facility.

A commemorative proof silver medal was issued in 2007 for the 400th year of getting the city status of Mannheim. On its obverse the facade of Mannheim Observatory is pictured on the left, while on the right the cross-section view is displayed. In the background the starry sky with constellations and asterisms are clearly identifiable including Hercules, Cassiopeia, Little and Big Dipper, Cepheus, Perseus, Auriga, Gemini, etc. Legend above is: "STERNWARTE", i. e. observatory, below the year of its opening 1774.

Mannheim 1  reverseMannheim 1 obverse

On the reverse the old-day coat of arms of Mannheim is pictured. Legend above is: "400 JAHRE MANNHEIN", i. e. 400 years of Mannheim, below years 1607-2007.

The observatory saw both good and bad days. There are entries in the visitors book of the Mannheim Observatory not only by many well-known colleagues, but also illustrious guests such as Wolfgang Amadeus Mozart, Benjamin Franklin, Envoy of the young United States, and even Arabic and other writings.

Mayer's astronomical work found its peak in the discovery of binary stars. The majority of the binary stars published in Bode's star chart of 1782 were observed by Mayer.

During the wars of the Napoleonic Era severe damage was inflicted on the Observatory. The tower was repeatedly shelled, instruments were destroyed and others damaged. Some disappeared in unexplained ways. The observatory was transferred to Karlsruhe and finally in 1898, was established on the Königstuhl near Heidelberg where today’s successor institution the State Observatory Heidelberg-Königstuhl is located. The observatory tower is now owned by the city and was restored in 1905-1906, and after the Second World War. Since 1958, the tower houses studio flats.