Berlin Observatory
The Berlin Observatory (Berliner Sternwarte) is a German astronomical institution with a series of observatories and related organizations in and around the city of Berlin in Germany, starting from the 18th century. It has its origins in 1700 when Gottfried Leibniz initiated the "Brandenburg Society of Science″ ("Sozietät der Wissenschaften") which would later (1744) become the Prussian Academy of Sciences ("Preußische Akademie der Wissenschaften"). The Society had no observatory but nevertheless an astronomer, Gottfried Kirch, who observed from a private observatory in Berlin. A first small observatory was furnished in 1711, financing itself by calendrical computations.
Normalnull
In 1878 reference heights were taken from the Amsterdam Ordnance Datum and transferred to the New Berlin Observatory in order to define the Normalhöhenpunkt 1879. Normalnull has been defined as a level going through an imaginary point 37.000 m below "Normalhöhenpunkt 1879". When the New Berlin Observatory was demolished in 1912 the reference point was moved east to the village of Hoppegarten (now part of the town of Müncheberg, Brandenburg, Germany).