Peter Andreas Hansen
Encyclopedia
Peter Andreas Hansen was a Danish
astronomer
, was born at Tønder
, Schleswig
.
, and exercised it at Berlin
and Tønder
, 1818–1820. He had, however, long been a student of science; and Dr Dircks, a physician practising at Tønder, 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.
Thence he passed on to Gotha
as director of the Seeberg observatory; nor could he be tempted to relinquish the post by successive invitations to replace F.G.W. Struve at Dorpat in 1829, and F.W. Bessel at Königsberg
in 1847. 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.
In 1838 he published a revision of the lunar theory
, entitled Fundamenta nova investigationis, &c., and the improved Tables of the Moon ("Hansen's Lunar Tables") based upon it were printed in 1857, at the expense of the British government, their merit being further recognized by a grant of £1000, and by their adoption in the Nautical Almanac
as from the issue for the year 1862, and other Ephemerides. A theoretical discussion of the disturbances embodied in them (long familiarly known to lunar experts as the Darlegung) appeared in the Abhandlungen of the Saxon Academy of Sciences in 1862–1864. At the time of publication of Hansen's Tables of the Moon in 1857, astronomers generally believed that the lunar theory was at last complete; but within about a decade, it was noticed, and shown by Simon Newcomb
, that the optimism had been unfounded: deviations between computed and observed positions began to grow at a rate showing that further refinement was necessary. For some years Hansen's theory continued to be used with Newcomb's corrections (from the Nautical Almanac's issue for 1883), but it was eventually (as from 1923) superseded by E W Brown
's theory.
Hansen twice visited England
and was twice (in 1842 and 1860) the recipient of the Gold Medal of the Royal Astronomical Society
. He communicated to that society in 1847 an able paper on a long-period lunar inequality (Memoirs Roy. Astr. Society, xvi. 465), and in 1854 one on the moon's figure, advocating the mistaken hypothesis of its deformation by a huge elevation directed towards the earth (ib. xxiv. 29). He was awarded the Copley Medal
by the Royal Society
in 1850, and his Solar Tables, compiled with the assistance of Christian Olufsen, appeared in 1854. Hansen gave in 1854 the first intimation that the accepted distance of the sun was too great by some millions of miles (Month. Notices Roy. Astr. Soc. xv. 9), the error of J.F. Encke
's result having been rendered evident through his investigation of a lunar inequality. In 1865, he was elected a foreign member of the Royal Swedish Academy of Sciences
.
He died on 28 March 1874, at the new observatory in the town of Gotha, erected under his care in 1857.
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
, was born at Tønder
Tønder
Tønder is a municipality in Region of Southern Denmark on the Jutland peninsula in south Denmark. The municipality covers an area of 1,278 km², and has a total population of 40,367...
, Schleswig
Schleswig
Schleswig or South Jutland is a region covering the area about 60 km north and 70 km south of the border between Germany and Denmark; the territory has been divided between the two countries since 1920, with Northern Schleswig in Denmark and Southern Schleswig in Germany...
.
Biography
The son of a goldsmith, Hansen learned the trade of a watchmaker at FlensburgFlensburg
Flensburg is an independent town in the north of the German state of Schleswig-Holstein. Flensburg is the centre of the region of Southern Schleswig...
, and exercised it at Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
and Tønder
Tønder
Tønder is a municipality in Region of Southern Denmark on the Jutland peninsula in south Denmark. The municipality covers an area of 1,278 km², and has a total population of 40,367...
, 1818–1820. He had, however, long been a student of science; and Dr Dircks, a physician practising at Tønder, prevailed with his father to send him in 1820 to Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...
, where he won the patronage of H.C. Schumacher
Heinrich Christian Schumacher
Heinrich Christian Schumacher was a German-Danish astronomer.-Biography:He was born at Bramstedt, in Holstein, and studied at Kiel, Jena, Copenhagen, and Göttingen. In 1810, he became adjunct professor of astronomy in Copenhagen...
and attracted the personal notice of King Frederick VI
Frederick VI of Denmark
Frederick VI reigned as King of Denmark , and as king of Norway .-Regent of Denmark:Frederick's parents were King Christian VII and Caroline Matilda of Wales...
. 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
Altona, Hamburg
Altona is the westernmost urban borough of the German city state of Hamburg, on the right bank of the Elbe river. From 1640 to 1864 Altona was under the administration of the Danish monarchy. Altona was an independent city until 1937...
, 1821–1825.
Thence he passed on to Gotha
Gotha (town)
Gotha is a town in Thuringia, within the central core of Germany. It is the capital of the district of Gotha.- History :The town has existed at least since the 8th century, when it was mentioned in a document signed by Charlemagne as Villa Gotaha . Its importance derives from having been chosen in...
as director of the Seeberg observatory; nor could he be tempted to relinquish the post by successive invitations to replace F.G.W. Struve at Dorpat in 1829, and F.W. Bessel at Königsberg
Königsberg
Königsberg was the capital of East Prussia from the Late Middle Ages until 1945 as well as the northernmost and easternmost German city with 286,666 inhabitants . Due to the multicultural society in and around the city, there are several local names for it...
in 1847. The problems of gravitational astronomy engaged the chief part of Hansen's attention. A research into the mutual perturbations of Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
and Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.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.
In 1838 he published a revision of the lunar theory
Lunar theory
Lunar theory attempts to account for the motions of the Moon. There are many irregularities in the Moon's motion, and many attempts have been made over a long history to account for them. After centuries of being heavily problematic, the lunar motions are nowadays modelled to a very high degree...
, entitled Fundamenta nova investigationis, &c., and the improved Tables of the Moon ("Hansen's Lunar Tables") based upon it were printed in 1857, at the expense of the British government, their merit being further recognized by a grant of £1000, and by their adoption in the Nautical Almanac
Nautical Almanac
Nautical Almanac can refer to:* Nautical almanac - a publication describing the positions and movements of celestial bodies* American Ephemeris and Nautical Almanac - first published in 1852* U.S...
as from the issue for the year 1862, and other Ephemerides. A theoretical discussion of the disturbances embodied in them (long familiarly known to lunar experts as the Darlegung) appeared in the Abhandlungen of the Saxon Academy of Sciences in 1862–1864. At the time of publication of Hansen's Tables of the Moon in 1857, astronomers generally believed that the lunar theory was at last complete; but within about a decade, it was noticed, and shown by Simon Newcomb
Simon Newcomb
Simon Newcomb was a Canadian-American astronomer and mathematician. Though he had little conventional schooling, he made important contributions to timekeeping as well as writing on economics and statistics and authoring a science fiction novel.-Early life:Simon Newcomb was born in the town of...
, that the optimism had been unfounded: deviations between computed and observed positions began to grow at a rate showing that further refinement was necessary. For some years Hansen's theory continued to be used with Newcomb's corrections (from the Nautical Almanac's issue for 1883), but it was eventually (as from 1923) superseded by E W Brown
Ernest William Brown
Ernest William Brown FRS was a British mathematician and astronomer, who spent the majority of his career working in the United States....
's theory.
Hansen twice visited England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
and was twice (in 1842 and 1860) the recipient of the Gold Medal of the Royal Astronomical Society
Gold Medal of the Royal Astronomical Society
-History:In the early years, more than one medal was often awarded in a year, but by 1833 only one medal was being awarded per year. This caused a problem when Neptune was discovered in 1846, because many felt an award should jointly be made to John Couch Adams and Urbain Le Verrier...
. He communicated to that society in 1847 an able paper on a long-period lunar inequality (Memoirs Roy. Astr. Society, xvi. 465), and in 1854 one on the moon's figure, advocating the mistaken hypothesis of its deformation by a huge elevation directed towards the earth (ib. xxiv. 29). He was awarded the Copley Medal
Copley Medal
The Copley Medal is an award given by the Royal Society of London for "outstanding achievements in research in any branch of science, and alternates between the physical sciences and the biological sciences"...
by the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1850, and his Solar Tables, compiled with the assistance of Christian Olufsen, appeared in 1854. Hansen gave in 1854 the first intimation that the accepted distance of the sun was too great by some millions of miles (Month. Notices Roy. Astr. Soc. xv. 9), the error of J.F. Encke
Johann Franz Encke
Johann Franz Encke was a German astronomer. Among his activities, he worked on the calculation of the periods of comets and asteroids, measured the distance from the earth to the sun, and made observations on the planet Saturn.-Biography:Encke was born in Hamburg, where his father was a...
's result having been rendered evident through his investigation of a lunar inequality. In 1865, he was elected a foreign member of the Royal Swedish Academy of Sciences
Royal Swedish Academy of Sciences
The Royal Swedish Academy of Sciences or Kungliga Vetenskapsakademien is one of the Royal Academies of Sweden. The Academy is an independent, non-governmental scientific organization which acts to promote the sciences, primarily the natural sciences and mathematics.The Academy was founded on 2...
.
He died on 28 March 1874, at the new observatory in the town of Gotha, erected under his care in 1857.
Further reading
- Vierteljahrsschrift astr. Gesellschaft, x. 133;
- Month. Notices Roy. Astr. Society, xxxv. 168;
- Proc. Roy. Society, xxv. p. V.;
- R Wolf, Geschichte der Astronomie, p. 526;
- Wochenschrift für Astronomie, xvi. 207 (account of early years by E Heis);
- Allgemeine deutsche Biographie (C Bruhns).
External links
- Awarding of RAS gold medal, 1842: MNRAS 5 (1842) 158
- Awarding of RAS gold medal, 1860: MNRAS 20 (1860) 154