The photographic plate archive contains more than 35,000 historical photographs of planets, comets, stars, nebulae, and other celestial bodies, which were recorded on photographic plates between 1911 and 1990 with the various telescopes of Hamburg Observatory. In addition, many plates from Vatican Observatory, Mount Wilson Observatory, and the European Southern Observatory can be inspected. Of particular interest are the images of the moon by Bernhard Schmidt from 1917 (see also: Schmidt-Museum) and the rare images of the solar eclipses of the years 1912 and 1929.