Bessel

Bessel, FRIEDRICH WILHELM, an eminent Prussian astronomer, born at Minden in 1784. Successively a merchant's clerk, a supercargo on board ship, and a practical astronomer, he was in 1810 appointed director of the observatory at Königsberg, and professor of Astronomy there. In 1818 he published his Fundamenta Astronomice—a work which was of the highest value to astronomers; and in 1830 his Tabulae Regiomontane. Among the numerous papers may be mentioned his treatise on the precession of the equinoxes. After a series of three years' observations he succeeded in determining the annual parallax of the fixed star 61 Cygni (see STARS). In the years 1824-33 Bessel made a series of 75,011 observations in 536 sittings, and completed a catalogue of stars (extending to the ninth magnitude) within the zone from 15° N. to 15° S. declination; and published Astronomische Untersuchungen (1842) and other works. His Popular Lectures on Astronomy were published two years after his death, which took place March 14, 1846. He was a thoroughly practical man of science, was remarkable for the precision of his calculations, introduced many new methods, and greatly forwarded the science of astronomy.