Christen Sørensen Longomontanus
Christen Sørensen Longomontanus | |
|---|---|
 Christen Sørensen Longomontanus | |
| Born | 4 October 1562 |
| Died | 8 October 1647(aged 85) |
| Nationality | Danish |
| Alma mater | University of Rostock |
| Scientific career | |
| Fields | Astronomy |
| Institutions | University of Copenhagen |
Christen Sørensen Longomontanus(also asLongbergorSeverin) (4 October 1562 – 8 October 1647) was aDanishastronomer.
The nameLongomontanuswas aLatinizedform of the name of the village of Lomborg,Jutland,Denmark,where he was born. His father, a laborer called Søren, or Severin, died when Christen was eight years old. An uncle took charge of the child, and had him educated atLemvig;but after three years sent him back to his mother, who needed his help to work the fields. She agreed that he could study during the winter months with the clergyman of the parish; this arrangement continued until 1577, when the ill-will of some of his relatives and his own desire for knowledge caused him to run away toViborg.[1]
There he attended thegrammar school,working as a labourer to pay his expenses, and in 1588 went toCopenhagenwith a high reputation for learning and ability. Engaged byTycho Brahein 1589 as his assistant in his great astronomical observatory ofUraniborg,he rendered invaluable service for eight years.[1]He held Tycho Brahe in the highest regard and always supported his system and tried to improve upon it throughout his life.[2]However, he did disagree with the Tycho Brahe's system in some regards, he believed that the earth rotated unlike his master's theory that it was immobile.[2]During this time,Keplerjoined the two in trying to come up with a theory on how to predict longitude at oppositions with complete accuracy. Longomontanus used Mars as a model for this.[3]Having left the island ofHvenwith his master, he obtained his discharge at Copenhagen on 1 June 1597, in order to study at some German universities. He rejoined Tycho atPraguein January 1600, and having completed the Tychonic lunar theory, turned homeward again in August.[1]Soon after this, Tycho Brahe’s untimely demise happened. After Tycho managed to become a mathematician that served the Emperor Rudolph II, he died in October 1601. The Emperor had to appoint a new Mathematician. When doing so, the expected choice would have been Longomontanus since he was Tycho’s preferred choice. However, Longomontanus was gone during this time in Denmark and Johannes Kepler was there, so he was anointed.[4]
He visitedFrauenburg,whereCopernicushad made his observations, took a master's degree atRostock,and at Copenhagen found a patron inChristian Friis,chancellor of Denmark, who employed him in his household. Appointed in 1603 rector of the school of Viborg, he was elected two years later to a professorship in theUniversity of Copenhagen,and his promotion to the chair ofmathematicsensued in 1607. This post was held by Longomontanus till his death in 1647.[1]
Longomontanus was not an advanced thinker. He adhered to Tycho's erroneous views aboutrefraction,believed thatcometswere messengers of evil, and imagined that he hadsquared the circle.He found that the circle whose diameter is 43 has for its circumference the square root of 18252 which gives 3.14185... for the value of π.John Pelland others tried in vain to convince him of his error. In 1632 he started the construction of theRundetårn(a stately astronomical tower in Copenhagen), but did not live to witness its completion. KingChristian IV of Denmark,to whom he dedicated hisAstronomia Danica,an exposition of the Tychonic system of the universe, conferred upon him thecanonryofLundeninSchleswig.[1]
Longomontanus's major contribution to science was to develop Tycho'sgeoheliocentricmodel of the universe empirically and publicly to common acceptance. When Tycho died in 1601, his program for the restoration of astronomy was unfinished. The observational aspects were complete, but two important tasks remained, namely the selection and integration of the data into accounts of the motions of theplanets,and the presentation of the results on the entire program in the form of a systematic treatise. Longomontanus assumed the responsibility and fulfilled both tasks in his voluminousAstronomia Danica(1622). Regarded as the testament of Tycho, the work was eagerly received in seventeenth-century astronomical literature. The book was highly accredited and many famous owners included Chrstopher Wren, Christiaan Huygens as well as theRoyal Greenwich Observatoryin England. The book mainly compared the three world systems of the time, these included the Copernicus, Tycho Brahe and Ptolemy schools of thought.[2]But unlike Tycho's, the geoheliocentric model of Longomontanus gave the Earth a proper daily rotation (as in the models ofUrsusandRoslin). It is therefore sometimes called the 'semi-Tychonic' system.[5]The book was reprinted in 1640 and 1663, which indicates its popularity and the interest in the semi-Tychonic system in this period.
Having originally worked on calculating theMartianorbitfor Tycho withKepler,he had already modelled its orbit in his geoheliocentric model to an error inlongitudeof under 2arcminuteswhen Kepler had still only achieved 8 arcminutes error in hisheliocentricsystem, as he had not yet usedellipticalorbits.
Some historians claim Kepler’s 1627Rudolphine Tables,based on Tycho Brahe’s observations, were more accurate than any previous tables. But nobody has ever demonstrated they were more accurate than Longomontanus’s 1622Danish Astronomytables, also based upon Tycho’s observations.[citation needed]
Publications[edit]
His major works in mathematics and astronomy were:
- Systematis Mathematici, etc.(1611)
- Cyclometria e Lunulis reciproce demonstrata,etc. (1612)
- Disputatio de Eclipsibus(1616)
- Astronomia Danica,etc. (1622)
- Astronomia Danica(in Latin). Amsterdam: Willem Jansz Blaeu. 1622.
- Disputationes quatuor Astrologicae(1622)
- Pentas Problematum Philosophiae(1623)
- De Chronolabio Historico, seu de Tempore Disputationes tres(1627)
- Geometriae quaesita XIII. de Cyclometria rationali et vera(1631)
- Inventio Quadraturae Circuli(1634)
- Disputatio de Matheseos Indole(1636)
- Coronis Problematica ex Mysteriis trium Numerorum(1637)
- Problemata duo Geometrica(1638)
- Problema contra Paulum Guldinum de Circuli Mensura(1638)
- Introductio in Theatrum Astronomicum(1639)
- Rotundi in Plano, etc.(1644)
- Admiranda Operatio trium Numerorum 6, 7, 8,etc. (1645)
- Caput tertium Libri primi de absoluta Mensura Rotundi plani,etc. (1646)[1]
Eponymy[edit]
- Thelunar craterLongomontanuswas named after him. It is located near theTycho crater.[6]
References[edit]
- ^abcdefChisholm 1911.
- ^abcKragh, Helge. (2015). Georgius Frommius (1605–1651) and Danish Astronomy in the Post-Tychonian Era. Acta Baltica Historiae et Philosophiae Scientiarum. 3. 45-68. 10.11590/abhps.2015.1.03.
- ^Carman, Christián C. (2020-05-01)."Longomontanus' Model for the Longitudes of Mars".Journal for the History of Astronomy.51(2): 162–186.Bibcode:2020JHA....51..162C.doi:10.1177/0021828620923802.ISSN0021-8286.S2CID220124653.
- ^"Christian Longomontanus - Scientist of the Day".Linda Hall Library.2019-10-04.Retrieved2020-12-18.
- ^See Schofield'sThe Tychonic and semi-Tychonic world systemsin Wilson & TatonPlanetary astronomy from the Renaissance to the rise of astrophysics1989 CUP. Mere diagrams of the Tychonic system would actually be indistinguishable from this semi-Tychonic system, unless they indicated whether the Earth or the fixed stars rotated daily.
- ^(in Latin)This is not a coincidence,as explainsGiambattista Riccioli,who named it.
- This article incorporates text from a publication now in thepublic domain:Chisholm, Hugh,ed. (1911). "Longomontanus, Christian Severin".Encyclopædia Britannica.Vol. 16 (11th ed.). Cambridge University Press. p. 985.
External links[edit]
- Biography fromDansk Biografisk Lexicon(1887–1905 – in Danish)
- Longomontanus's'Astronomia Danica',in its original Latin, at the internet archive.
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