The 24-meter dome that houses the Great Refractor of Potsdam (Große Refraktor), a double telescope of 1899 with a 80cm (31.5") and 50 cm (29.5") lenses, one of the world's largest telescopes of the time. it is now preserved for public visits inside the Leibniz Institute for Astrophysics Potsdam near Berlin, a successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory Potsdam (AOP) founded in 1874.