Encke, JOHANN FRANZ

Encke, JOHANN FRANZ, astronomer, was born at Hamburg, September 23, 1791. After studying at Göttingen, he served, during the campaign of 1813-14, in the artillery of the Hanseatic legion, and in 1815 in the Prussian army, as lieutenant of artillery. On the establishment of peace he left the service, and became assistant, and afterwards principal astronomer, in the observatory of Seeberg, near Gotha. In 1825, chiefly at the instigation of Bessel, he was called to Berlin as secretary of the Academy of Sciences and director of the observatory. While at Gotha, the astronomical prize offered by Cotta was awarded to Encke by the judges Gauss and Olbers, for his determination of the orbit of the comet of 1680. This led him to solve another problem, which had been proposed along with the other—viz. the distance of the sun. The solution, by means of the two transits of Venus in 1761 and 1769, is published in two separate tracts (Die Entfernung der Sonne, Gotha, 1822-24). In 1819 he proved that the comet discovered by Pons, November 26, 1818, revolves in the hitherto incredibly short period of about 1200 days, and had been already observed in 1786, 1795, and 1805. It has since gone by the name of Encke's comet, and has appeared regularly; the period of its recurrence being 3.29 years, or about 3$\backslash frac\{1\}\{2\}$ years (see COMET). Encke's researches on this subject are contained in the Transactions of the Berlin Academy. In 1830 he undertook to edit the Berlin Astronomical Almanac, in which he published a number of astronomical treatises (separately published, 3 vols. 1866). Four volumes appeared of his Astronomical Observations at the Berlin Observatory (1840-56). He died 2d September 1865. See his Life by Bruhns (Leip. 1869).