Born in Nieder-Cunesdorf, near Dresden, Tempel learned drawing and became a lithographer. He practiced his trade in German towns, in Denmark, and finally in Italy, where he became known as a proficient amateur astronomer. Of modest culture but ingenious, he achieved fame in 1859 for the discovery, in Venice, of a comet that now bears his name. For some time he worked at the Observatory in Marseille, where he discovered ten comets and several asteroids. Expelled from France in 1870 because of his German nationality, he was hired by the Brera Observatory in Milan. In 1875, he was appointed astronomer of the Arcetri Observatory in Florence, where he remained until his death. In Arcetri, he made beautiful drawings of celestial objects and discovered his last comet, 1877 V., working with the great equatorial built by Giovanni Battista Donati (1826-1873).