part of the grounds were used in 1912 for a new road, which has been called Enckestraße since 1927. From 1913, the street was built up with, among others, the (1922). Berlin-Babelsberg Observatory In 1913, the Berlin Observatory moved again after 78 years in its second home to Babelsberg (since then it is often referred to as Babelsberg Observatory). The Observatory in Kreuzberg was cleared out and torn down in August 1913. The sale of the land covered the cost of the construction of the new building (1.1 million Goldmarks and the purchase of new instruments to the sum of 450.000 Goldmarks). The land itself on the Babelsberg in the Schlosspark cost the Royal establishment nothing. The hill giving the area its name is situated about three kilometers north-east of the Telegrafenberg. The construction of the main building was carried out between 1911 and 1913 by Mertins, W. Eggert, Beringer und E. Wagnernach following the design of Thür and Brüstlein. The move was supervised by the precision engineering company, who also manufactured an astrograph and a meridian circle. The first of the new instruments arrived in spring 1914. In the year after, the placing of a 65 cm refractor was completed; it was the first large astronomical instrument from Carl Zeiss in Jena. In 1924 followed the completion of a 120 cm reflecting telescope, at the time the second-largest telescope in the world and the largest in Europe. After the Second World War, the reflecting telescope was dismantled and was shipped off to the Soviet Union as reparations (a fate shared by other observing instruments) It was sent to the Crimea complete with its dome;– to reconstruct the Crimean Astrophysical Observatory, Simejis, destroyed in the war. – where it is still in service today. In 2002, the remaining torso of the building was fully restored and completed and received a new dome; since then the library of the Leibniz-Institut für Astrophysik Potsdam has been accommodated there. Struve remained as director until his death in 1920 – up until 1918 it was still called Königliche Sternwarte zu Berlin-Babelsberg (or Berlin-Neubabelsberg) and then from 1918 until 1946 it became the at Berlin-Babelsberg. After Hermann Struve, the directorship passed over to Paul Guthnick in 1921 and he remained as a long-serving director until 1946. Apart from this post, his main body of work concerned the photometry of stars and the investigation of variable