Description

Geographical position 

Østervold Observatory near Rosenborg Castle, Copenhagen University Observatory (Københavns Universitet  Astronomisk Observatoriet), Botanical Garden (Botanisk Have), Denmark

See also:
Ole Rømer Tusculanum Observatory, Taastrup (1704)
Rundetårn (Round Tower), Copenhagen, Denmark (1637)
New observatory: Brorfelde Observatoriet, Copenhagen University (1953).

Location 

Latitude 55°41’13’’ N, Longitude 12°34’33’’ E, Elevation ...m above mean sea level.

IAU observatory code 

035

Description of (scientific/cultural/natural) heritage 

The Østervold Observatory (1859-61) in Neoclassical style is a three-winged building, designed by Hans Christian Hansen (1803--1883), who worked 18 years in Greece. The large dome was on the central building. It replaced the University’s old observatory at Rundetårn (1642).

The first observatories in Denmark were Tycho Brahe’s Uraniborg and Stjerneborg (Stellaeburgum) on the Island Hven (now Ven, Sweden).

           

The Østervold Observatory was built on the old bastioned fortifications in the Botanical Garden. Heinrich Louis d’Arrest (1822--1875), who was professor of astronomy at the university from 1857 to 1875, made the plans. He studied at the University of Berlin, and worked from 1848 to 1957 in Leipzig Observatory. He discovered the comet 6P/d’Arrest (1844), and the asteroid 76 Freia (1862). In Copenhagen, d’Arrest discovered 342 Deep-Sky-Objects like NGC 1 in 1861, NGC 26 and NGC 358 in 1865. He also started astrophysics, especially spectroscopy, and compiled a nebula catalogue "Siderum Nebulosorum Observationes Havnienses" (1867), containing 1942 nebulas with 4900 positions. He studied especially the Coma galaxy cluster, which he analysed through systematic observations from 1861 to 1867.

      

His observer Hans Carl Frederik Christian Schjellerup (1827--1887) used the meridian circle and compiled a large astronomical catalogue with 10,000 positions of stars up to the 8th or 9th magnitude. In addition, in 1866, Schjellerup published a catalogue of red stars, which were of particular interest to the then newly introduced spectroscopy -- the red stars were supposed to be final stages of the stellar evolution. Inspired by a manuscript by the Persian astronomer Abd ar-Rahman as-Sufi (903--986), in which he offered a careful description of the fixed stars based on his own observations, he translated it from the arabic original text, and became interested in brightnesses of fixed stars -- in the tradition of Argelander. Schjellerup became an early historian of astronomy.

   

The next director of the Østervold Observatory was Thorvald Nicolai Thiele (1838--1910), more a mathematician than an astronomer. He developed a new method of determining the orbit of Binary stars, and introduced computational mathematical astronomy like statistics and the three-body problem. His books were published in German, French and English.

   

Svante Elis Strömgren (1870--1947) studied astronomy at the University of Lund from 1887, his dissertation had the topic "Determination of the Orbit of Comet 1890 II" (1898). From 1901 to 1907 he worked at the University of Kiel as an assistant to the editor of the "Astronomische Nachrichten". In 1907, he was called as professor of astronomy at the University of Copenhagen and director of the Copenhagen Østervold Observatory. He devoted himself to celestial mechanics, especially binaries, the three-body problem, and the orbit determination of many comets. Strömgren was active in several commissions of the International Astronomical Union, member of the Royal Astronomical Society and several academies, and chairman of the Astronomical Society ("Astronomische Gesellschaft") from 1921 to 1930.

   

Bengt (Georg Daniel) Strömgren (1908--1987) studied at the University of Copenhagen, in 1929, he completed his doctoral thesis on a topic in celestial mechanics. After a longer guest stay at the University of Chicago and the Yerkes Observatory in the USA, he returned to Denmark in 1938 where he took up a professorship in astronomy at the University of Copenhagen, and succeeded his father as director of the Copenhagen Observatory in 1940.
Due to insufficient government funding, Bengt Strömgren left Denmark in 1951 and became director of the Yerkes Observatory and the McDonald Observatory. Six years later, in 1957, he was appointed senior professor of theoretical astrophysics at the Institute for Advanced Study in Princeton, where he took over Albert Einstein’s office. In 1967, he returned to Denmark where he was director of "Nordita", a network of research institutes of the Nordic countries, for several years. Strömgren was Secretary General of the International Astronomical Union from 1948 to 1955 and its President from 1975 to 1977.
His contributions to astrophysics were in the field of cosmochemistry. he determined the chemical (atomic) composition of stars, which differed greatly from previous estimates. He realised in 1932 that hydrogen is the main component of stars, and helium the second most common. After Rupert Wild’s discovery of the importance of the H^- ion (1939), he developed a realistic model of the solar atmosphere (1940). Bengt Strömgren studied the physics of the "Strömgren sphere" named after him, the H-II region around a hot O- or B-star with UV radiation in which all hydrogen exists in ionised form. In addition, he developed the new photometric Strömgren-Crawford-System, the narrow band system u, b, v, y, m_beta (1950s and 1960s). This multi-colour system is the basis to derive physical parameters like luminosity, mass, age, temperature, metallicity, ...)

Due to light pollution and vibrations from the Boulevard railway, the observatory no longer has any scientific significance. A new modernized astronomical university observatory, the Brorfelde Observatory, was opened in 1953.

History 

  

Instruments

• 27.5-cm-Refractor (focal length 4.9m), made by Merz of Munich (1861),
  now displayed at the Steno Museum in Århus
  
  
• Meridian circle, made by Pistor & Martins of Berlin (1861)
  
  
• 36/20-cm-Double-Refractor (36-cm-visual lens, focal length 4.9m, 20-cm-photographic lens,
  focal length of 4.8m, 15cm glass plates), 1895.

   

Modern meridian circles and two satellites, Hipparcos and Gaia, have revolutionized the whole of astronomy with new astrometry for two billion stars. 

Directors

• 1857/62 to 1875 -- Heinrich Louis d’Arrest (1822--1875)
• 1875 to 1907 -- Thorvald Nicolai Thiele (1838--1910)
• 1907 to 1940 -- Svante Elis Strömgren (1870--1947)
• 1940 to 1951 -- Bengt Strömgren (1908--1987)

Discovered Asteroids: 8

• (3312) Pedersen    --  24. September 1984
• (5165) Videnom    --  11. Februar 1985
• (5427) Jensmartin    --  13. Mai 1986
• (7743) 1986 JA    --  2. Mai 1986
• (8261) 1985 RD    --  11. September 1985
• 1985 FE                    --  27. März 1985
• (22282) 1985 RA    --  11. September 1985
• (24642) 1984 SA    --  22. September 1984

State of preservation 

      

The Østervold Observatory building still exists, but it is no longer used for astronomy. The building is in good condition.

Comparison with related/similar sites 

The Østervold Observatory is an observatory with one prominent 7-m-dome e.g. like Tartu Observatory (1810).

Threats or potential threats 

no threats

Present use 

   

The Østervold Observatory building still exists, but it is no longer used for astronomy, but it was often used among ornithologists. The buildings today house the "Institute for Science Didactics", University of Copenhagen.

Astronomical relevance today 

The Østervold Observatory is no longer used for astronomy since the 1950s. The 27.5-cm-Merz Refractor (1861) was moved to the Steno Museum in Århus.

A new university observatory was founded, the Brorfelde Observatory (1953--1996) near the town of Holbæk. There is a modern meridian circle and a Schmidt telescope available; also the double astrograph was moved to Brorfelde.

In addition, there is the 1.5-m-Danish Reflector at ESO, La Silla, Chile.

References

Bibliography (books and published articles) 

• Jensen, Thomas of Bornholm: Personal communication (Nov. 24, 2022).
  
  
• Lundmark, Knut: Svante Elis Strömgren. In: Monthly Notices of the Royal Astronomical Society 108 (1948), p. 37-41.
  
  
• Poulsen, Erling: Centuries of Astronomy -- Astronomy in Denmark (2009),  (https://web.archive.org/web/20090202090040/http://rundetaarn.dk/engelsk/observatorium/history.htm))
  
  
• Schjellerup, Hans Carl Frederik Christian: Stjernefortegnelse indeholdende 10000 Positioner af teleskopiske Fixstjerner imellem -15 og +15 Graders Deklination. Kopenhagen 1864.
  
  
• Schjellerup, Hans Carl Frederik Christian: Eine Uranometrie aus dem zehnten Jahrhundert. In: Astronomische Nachrichten 74 (1869), Issue 7, p. 97-104.
  
  
• Schjellerup, Hans Carl Frederik Christian: Description des Étoiles Fixes, composée au milieu du dixième siècle de notre ère par l’Astronome Persan Abd-al-Rahman al-S├╗fi. St. Petersburg 1874.
  
  
• Strömgren, Bengt: On the chemical composition of the solar atmosphere. In: Festschrift für Elis Strömgren. Kopenhagen 1940, p. 218.
  
  
• Strömgren, Bengt: Astrophotometrie. Kap. 3 in: Astrophysik. Ed. by Bengt Strömgren. Berlin: Springer 1937 (Bd. 26 des Handbuchs der Experimentalphysik).
  
  
• Strömgren, Elis & Bengt Strömgren: Lehrbuch der Astronomie. Berlin: Springer 1933.
  
  
• Thiele, Thorvald N.: Sur la compensation de quelques erreurs quasi-systématiques par la méthode des moindres carrés. Copenhagen : C.A. Reitzel 1880.
  
  
• Thiele, Thorvald N.: Theory of Observations. London: C. & E. Layton 1903.
  
  
• Thiele, Thorvald N.: Interpolationsrechnung. Leipzig: B.G. Teubner 1909.
  
  
• Vinter-Hansen, Julie M.: Obituary: Svante Elis Strömgren. In: The Observatory 67 (1947), p. 142-143.
  
  
• Voigt, Hans-Heinrich: Bengt Strömgren (21. Januar 1908 -- 4. Juli 1987). In: Mitteilungen der Astronomischen Gesellschaft 73 (1990), p. 5-7.
  
  
• Wolfschmidt, Gudrun (Hg.): Astronomie im Ostseeraum -- Astronomy in the Baltic. Proceedings der Tagung des Arbeitskreises Astronomiegeschichte in der Astronomischen Gesellschaft in Kiel 2015. Hamburg: tredition (Nuncius Hamburgensis -- Beiträge zur Geschichte der Naturwissenschaften; Band 38) 2018.
  
  
• Zinner, Ernst: d’Arrest, Heinrich Louis. In: Neue Deutsche Biographie (NDB), Band 1. Berlin: Duncker & Humblot 1953, p. 398.

Links to external sites 

• Niels Bohr Institute, Astrophysics
  
  
• Østervold, Danmarks Natur- og L├ªgevidenskabelige Bibliotek, 2001
  
  
• Poulsen, Erling: Centuries of Astronomy Astronomy in Denmark

Links to external on-line pictures 

no information available