Friedrich Wilhelm Bessel

Friedrich Wilhelm Bessel (1784-1846) was a German astronomer and mathematician, born at Minden. He was a Prussian (a country in his time) astronomer of prominent ability, and is known for determining the positions of about 75,000 stars, obtaining accurate measurements of stellar distances, discovering the parallax of the fixed star 61 Cygne, following a study of the orbit of Uranus, and predicting the existence of an eighth planet.

He was professor of Mathematics at Königsberg, and director of the Observatory. His greatest work, "Fundamenta Astronomiæ," on which he spent 10 years, a marvel, like all he did, of patient toil and painstaking accuracy.