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Astro*Dictionary by Michael Erlewine





1 article for "Encke, Johann Franz"

Encke, Johann Franz [Astro*Index]


(1791-1865) German astronomer. Born at Hamburg; died at Spandau (near Berlin).

In 1819, he computed the orbit of a comet with a period of only 3.3 years (which is shorter than all other comets). The close approach of this comet, in 1835, to Mercury allowed the mass of that planet to be determined from perturbations on the orbit of the comet. His determination of the AU (95,300,000 miles) was too large by more than 2%.

See also: ♦ Astronomical Unit


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