Date of Birth: 1795
The circumstances of his father (who was a goldsmith) did not allow the young G. surrender entirely the study of his beloved science - mathematics, he had to deal with it in fits and starts; with love and devoted Hansen his spare time studying languages ??and the production of a variety of physical devices. Not being able to continue their favorite activities, Hansen went to the watchmaker in Flensburg, where in 1818 he moved to Berlin, where for years he continued to study the art of watchmaking; Returning home, he opened a workshop hours. In 1820, Hansen was able to travel to Copenhagen to Schumacher to study mathematics and astronomy, and in 1821 he became its permanent employee for arc measurements in Holstein; in 1825 he was invited by the director of the observatory in Gotha in place Enke; Hansen here he remained until his death (1874).
In Gotha Hansen built (1857) a new observatory. The outstanding work of G. brought him fame not only at home but also abroad. In 1846 he was made a Fellow of the Royal Saxon Society of Sciences, in 1865 - a member of the Berlin Academy of Sciences. From the works of G. special attention should be given work on perturbation theory in the movement of planets and comets ( "Auseinandersetzung einer zweckm & # 228; ssigen Methode zur Berechnung der absoluten St & # 246; rungen der kleinen Planeten"; "Darlegung der theoretischen Berechnung der in den Mondtafeln angewandten St & # 246; rungen ", etc.).; the result of his studies of motion of the Moon - "Tables de la Lune, construites d`apr & # 232; s le principe Newtonien de la gravita tion universelle", printed in 1857 by the British government, still used to this day. Tables of the Sun, published in conjunction with Olusfenom in 1853, too, have long been used and only recently replaced by a more accurate calculated Leverrier.
In addition to the perturbation theory, the theory of Hansen studied instruments (heliometer, equatorial, transit instrument), geodesy, Dioptrics and probability theory. Practical talents G. had nowhere to turn, albeit at a modest observatory, as the Gothic, he introduced various improvements in astronomical instruments. Astronomers Auvers, Wagner (former vice-director of the Pulkovo Observatory), Gould, Povalki, shop, etc. -. D. students