Encke, Johann Franz

Encke, Johann Franz (yō`hän fränts ĕng`kə), 1791–1865, German astronomer. He was assistant (1816–22) and director (1822–25) of the observatory at Seeberg (near Gotha) and director (from 1825) of the Berlin Observatory. He is known for his study of records of the orbit of the comet of 1680, for calculations—based on transits of Venus—of the earth's distance from the sun, and for his discovery of the division in Saturn's A ring that bears his name. Encke's comet (discovered by J. L. Pons in 1818) was named for him because he calculated its orbit, finding the period of recurrence to be 3.3 years, and accurately predicted the date of its return.

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Encke, Johann Franz 

Born Sept. 23, 1791, in Hamburg; died Aug. 26, 1865, in Spandau, now part of Berlin. German astronomer.

Encke graduated from the university in Göttingen. Beginning in 1816 he worked at the observatory near Gotha. From 1825 to 1863 he was director of the Berlin Observatory. During the same period, from 1828 to 1863, he was publisher of the Berliner astronomisches Jahrbuch, Encke studied the motion of the comet 1818, for which he detected secular acceleration of the mean motion, and established its periodicity.

WORKS

Gesammelte mathematische und astronomische Abhandlungen, vols. 1–3. Berlin, 1888–89.