Hansen, Peter Andreas

Family circumstances (father was a master of goldmaking) did not allow the young Hansen to completely indulge in the study of his favorite science - mathematics , he had to deal with it in snatches; Hansen also devoted his free time to learning languages ​​and making various physical devices with love. Unable to continue his favorite activities, Hansen joined the watchmaker in Flensburg , from where he moved to Berlin in 1818 , where he continued to study watchmaking for a year.

Returning to his homeland, he opened a watch workshop. In 1820, Hansen got the opportunity to go to Copenhagen to Schumacher to study mathematics and astronomy , and from 1821 he became his permanent associate in degree measurement in Holstein ; in 1825 he was invited by the director of the Gotu Observatory to the place of Enke ; Hansen remained here until his death in 1874 .

In Gotha, Hansen built a new observatory in 1857 .

In addition to the perturbation theory, Hansen was engaged in the theory of instruments (heliometer, equatorial, passive instrument), geodesy , diopter and probability theory.

Hansen’s practical talent had nowhere to turn around, although he introduced various improvements to astronomical instruments at such a modest observatory as the Gothic one. The astronomers Auvers , Wagner (former vice-director of the Pulkovo Observatory ), Gould , Povalki , Workshop, and others are Hansen's students.

The outstanding works of Hansen brought him fame not only at home, but also abroad. In 1846, he was made a member of the Royal Saxon Society of Sciences, in 1865 - a member of the Berlin Academy of Sciences.

In 1935, a crater on the visible side of the moon was named after Hansen.

Of the works of Hansen deserve special attention:

• work on the theory of perturbations in the motion of planets and comets, in particular:
  • "Auseinandersetzung einer zweckm ässigen Methode zur Berechnung der absoluten Störungen der kleinen Planeten"
  • "Darlegung der theoretischen Berechnung der in den Mondtafeln angewandten Stö rungen"
• the result of his studies of the motion of the moon - "Tables of the Moon, built on the principles of Newtonian universal gravitation " ( French Tables de la Lune, construites d'après le principe Newtonien de la gravitation universelle ), printed in 1857 . Astronomers of the time believed that the theory of moon motion was complete! But after about a decade C. Newcom found that such optimism was unfounded: the deviations between calculations and observations of the lunar coordinates grew at a speed proving that further refinement of the theory is necessary. For some time, the Hansen theory was used as amended by Newcom (in the issue of the Navigation Almanac for 1883), but in the end (at the beginning of the 20th century) was replaced by the theory of motion of the Moon of Brown .
• The tables of the Sun, published by Hansen together with Christian Olufsen in 1853, were also in use for a long time and only at the very end of the 19th century were replaced by more accurate ones calculated by Le Verrier .

• Kolchinsky I.G., Korsun A.A., Rodriguez M.G. Astronomers: A Biographical Reference. - 2nd ed., Revised. and additional .. - Kiev: Naukova Dumka, 1986. - 512 p.

• Hansen, Peter Andreas // Encyclopedic Dictionary of Brockhaus and Efron : 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
• Profile of Peter Andreas Hansen on the official website of the RAS