Photographic plates from the 1882 transit

Transit of Venus Plates

Images from photographic plates of the Transit of Venus (Venus crossing the face of the Sun), a very rare phenomenon that last occurred in 1874 and 1882. Wet bromo-iodide plates were used in 1874, but by 1882 dry collodion emulsion plates were available. The Naval Observatory and Transit of Venus Commission sent 8 parties around the world to observe each of the transits; the results were important for determining the scale of the solar system. Only 11 plates survive from the American 1882 expeditions; none of the plates from the American 1874 transit expeditions has survived. The next transits of Venus occur in 2004 and 2012.