Whether Bessel communicated such a course of reasoning to Fraunhofer, or whether that great artist arrived independently at like conclusions, we have been unable to ascertain with certainty.
Encke, Geddchtnissrede auf Bessel (Berlin, 1846); C. T.
Of these methods Bessel generally employed the first because of its simplicity, notwithstanding that it involved a resetting of the right ascension and declination of the axis of the tube with each reversal of the segments.
On the other hand it is not necessary to reset the telescope after each reversal of the segments.4 When Bessel ordered the Konigsberg heliometer, he was anxious to have the segments made to move in cylindrical slides, of which the radius should be equal to the focal length of the object-glass.
FRIEDRICH WILHELM BESSEL (1784-1846), German astronomer, was born at Minden on the 22nd of July 1784.
During an administration of nearly twenty-five years Pond effected a reform of practical astronomy in England comparable to that effected by Bessel in Germany.
Erman's Briefwechsel zwischen Olbers and Bessel (2 vols., Leipzig, 1852); Allgemeine Deutsche Biographie (S.
The most important part, however, which this type of instrument seems to have played in the history of astronomy arises from the fact that one of them was in the possession of Bessel at Konigsberg during the time when his new observatory there was being built.
Although Bessel was the first to systematically treat of these functions, it is to be noted that in 1732 Daniel Bernoulli obtained the function of zero order as a solution to the problem of the oscillations of a chain suspended at one end.
In 1812 Bessel measured with it the angle between the components of the double star 61 Cygni and observed the great comet of 1811.