Agnes Mary Clerke

“ The problems of gravitational astronomy engaged the chief part of Hansen’s attention. A research into the mutual perturbations of Jupiter and Saturn secured for him the prize of the Berlin Academy in 1830, and a memoir on cometary disturbances was crowned by the Paris Academy in 1850. ”

“ The son of a goldsmith, he learned the trade of a watchmaker at Flensburg, and exercised it at Berlin and Tondern, 1818–1820. He had, however, long been a student of science; and Dr Dircks, a physician practising at Tondern, prevailed with his father to send him in 1820 to Copenhagen, where he won the patronage of H. C. Schumacher, and attracted the personal notice of King Frederick VI. The Danish survey was then in progress, and he acted as Schumacher’s assistant in work connected with it, chiefly at the new observatory of Altona, 1821–1825. ”