Early German plans for southern observatories

As early as the 18th and 19th centuries, French and English observers were active in South Africa. Around the beginning of the 20th century, Heidelberg and Potsdam astronomers proposed a southern observatory. Then Göttingen astronomers suggested building an observatory in Windhoek for photographing the sky and measuring the solar constant. In 1910 Karl Schwarzschild (1873–1916), after a visit to observatories in the United States, pointed out the usefulness of an observatory in South West Africa, in a climate superior to that in Germany, giving German astronomers access to the southern sky. Seeing tests were begun in 1910 by Potsdam astronomers, but WW I stopped the plans. In 1928 Erwin Finlay‐Freundlich (1885–1964), inspired by the Hamburg astronomer Walter Baade (1893–1960), worked out a detailed plan for a southern observatory with a reflecting telescope, spectrographs and an astrograph with an objective prism. Paul Guthnick (1879–1947), director of the Berlin observatory, in cooperation with APO Potsdam and Hamburg, made a site survey to Africa in 1929 and found the conditions in Windhoek to be ideal. Observations were started in the 1930s by Berlin and Breslau astronomers, but were stopped by WWII. In the 1950s, astronomers from Hamburg and The Netherlands renewed the discussion in the framework of European cooperation, and this led to the founding of ESO in 1963.