Wilhelm Tempel was a German-born astronomer who discovered numerous deep sky objects and comets. After leaving his hometown in Saxony in 1837, he trained as a lithographer and worked in this profession in Copenhagen, Christiania (now Oslo), and Venice. In 1860 he went to Marseilles to work at the Observatory, in 1871 he joined Schiaparelli at Brera Observatory in Milan, and in 1874 he went to Arcetri Observatory. Tempel discovered the Merope Nebula (NGC 1435) in the Pleiades in October 1859. Later he discovered many more nebulous objects: 156 NGC entries were credited to him, of which at least 123 belong to real deep sky objects. He is also quoted for 13 original comet discoveries and five independent co-discoveries, as well as eight first rediscoveries of periodic comets; his original discoveries include 4 short-period comets (9P/Tempel 1, 10P/Tempel 2, 11D/Tempel-Swift, and the Leonid comet 55P/Tempel-Tuttle).