The Lake County Astronomical Society

Astronomy Bio...Johann Franz Encke

From the CompuServe Astronomy

Johann Franz Encke was born in 1791 in Hamburg, Germany. In 1811, Encke began his studies of mathematics in Goettingen as a pupil of C.F. Gauss. In May 1816 he moved to Seeberg to work as observer at the observatory there. In 1822 he was promoted Director of that observatory and in 1825 followed a call to be the Director of the Observatory at Berlin. He supervised the new construction of the observatory from 1832-35. In 1844 he became a professor at the University of Berlin and was allowed to lecture without receiving a doctorate.

Probably best known is his calculation of a cometary orbit, Encke followed a suggestion by J. L. Pons and calculated the orbital elements of a comet found by Pons in 1818. He suspected one of the three comets discovered in 1818 to be one already discovered by Encke in 1805. The comet was found to have a period of 3.3. years and Encke predicted its return for 1822. This return was only observable from the southern hemisphere and was seen by K. Ruemker from Australia. The importance of the predicted return based on the calculation by Encke was rewarded by the Astronomical Society of London with the presentation of a gold medal to him in 1823.

During Encke's directorship, the work at the Berlin observatory concentrated on the calculation of the orbits of asteroids and the influence of the big planets on these orbits. In 1846 J.G. Galle discovered the planet Neptune with the help of star charts edited by Encke. With the help of J.P. Wolfers and Bremiker, Encke also published 37 volumes (1830-66) of the 'Berliner Astronomisches Jahrbuch', an annual publication. These contain some still valuable articles on the problems of astronomical calculations.

Encke died in Spandau, near Berlin, in 1865. As with many of his contemporaries, he is honored by a lunar crater named after him. A division between the A- and F-ring around Saturn discovered in 1838 also bears his name (the Encke gap).