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Encyclopedia :: encyclopedia : Friedrich Bessel (Site not responding. Last check: 2007-11-03) |
 | | Friedrich Wilhelm Bessel (July 22, 1784 – March 17, 1846) was a German mathematician, astronomer, and systematizer of the Bessel functions (which, despite their name, were discovered by Daniel Bernoulli). |
 | | He narrowly beat Friedrich Georg Wilhelm Struve and Thomas Henderson, who measured the parallaxes of Vega and Alpha Centauri in the same year. |
 | | As well as helping determine the parallax of 61 Cygni, Bessel's precise measurements allowed him to notice deviations in the motions of Sirius and Procyon, which he deduced must be caused by the gravitational attraction of unseen companions. |
| www.hallencyclopedia.com /Friedrich_Bessel (535 words) |
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