Østervold Observatory
Encyclopedia
Østervold Observatory is a former astronomical
observatory
(IAU code 035) in Copenhagen
, Denmark
owned and operated by the University of Copenhagen
(Københavns Universitet). It opened in 1861 as a replacement for the University's old observatory at Rundetårn
.
. It had been inaugurated in 1642 as a replacement for Tycho Brahe
's Stjerneborg
, but during the early 19th century had become outdated as astronomical instruments grew bigger and bigger while the tower could not be expanded. In the same time, light pollution
from the surrounding city as well as vibrations caused by the still increasing traffic in the streets below had made the observations inaccurate.
In 1861 the observatory was moved to Østervold, where a new observatory was constructed on the old bastioned fortifications
of the city, which had become outdated and were being disabandonned. The well-known Russian-German astronomer, Heinrich Louis d'Arrest
, who had been appointed professor in astronomy at the university in 1857, was chosen to plan the new observatory. He used the observatory for his study of nebula
s, in 1867 publishing an astronomical catalog
ue of 1.942 nebulas with 4.900 positions. He also did significant work in spectroscopy
, and discovered, for the first time, the differences in the evolutionary state and spatial distribution of stars. While d'Arrest used the main telescope, observer H. C. F. C. Schjellerup used the Meridian circle for creating one of the most comprehensive astronomical catalogues of the time of stars of the 8th-9th magnitude
: 10,000 positions on 259 observation nights.
The next director of the Østervold Observatory was Thorvald N. Thiele
, a skilful mathematician who developed a new method of determining the orbit of Binary star
s. He founded the tradition for numerical computational mathematics, which has lasted up to modern times.
In 1907, Elis Strömgren
was appointed professor and director of the observatory, and under his direction the computational work continued.
During World War I
, the Central Bureau for Astronomical Telegrams
, founded by Astronomische Gesellschaft
in 1882, was moved from Kiel
, Germany
, to the Østervold Observatory. It remained located in Copenhagen until 1965, when it was moved to the Smithsonian Astrophysical Observatory
, Cambridge
, USA.
In 1940 Ellis Strömgren was succeeded by his son Bengt Strömgren
. He made the pioneering discovery that hydrogen
is the most abundant element in the stellar interior
, and he was the first to make the correct interpretation of the Hertzsprung–Russell diagram
(the relation between the total energy output from a star and its surface temperature was independently found by the Danish chemist and astronomer Ejnar Hertzsprung
and the American astronomer Henry Norris Russell
). Around 1950, he developed the UVBYß photoelectric system, which is still in use today.
In the 1950s, the Østervold Observatory was replaced by the Brorfelde Observatory
located near the town of Holbæk, it was provided with a very fine meridian circle and a Schmidt camera. It houses a 300 double reflector
with a focal depth of 4.9 m.
. The central wing is topped by a dome
. containing the main instrument. The side wings contained residences for the director, the observer as well as assistants. To secure the best possible foundation of the instruments, the foundation of the building rests on the original, true ground surface, penetrating the entire depth of the ramparts on which the building stands. This took 1/3 of the bricks used for the entire complex.
1875-1907: Thorvald N. Thiele
1907-1940: Elis Strömgren
1940-1951. Bengt Strömgren
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
observatory
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...
(IAU code 035) in 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...
, Denmark
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...
owned and operated by the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
(Københavns Universitet). It opened in 1861 as a replacement for the University's old observatory at Rundetårn
Rundetårn
The Rundetårn is a 17th-century tower located in central Copenhagen, Denmark. One of the many architectural projects of Christian IV, it was built as an astronomical observatory...
.
History
The first astronomical observatory operated by the University of Copenhagen was RundetårnRundetårn
The Rundetårn is a 17th-century tower located in central Copenhagen, Denmark. One of the many architectural projects of Christian IV, it was built as an astronomical observatory...
. It had been inaugurated in 1642 as a replacement for Tycho Brahe
Tycho Brahe
Tycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
's Stjerneborg
Stjerneborg
Stjerneborg was Tycho Brahe's underground observatory next to his palace-observatory Uraniborg, located on the island of Hven in Oresund....
, but during the early 19th century had become outdated as astronomical instruments grew bigger and bigger while the tower could not be expanded. In the same time, light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...
from the surrounding city as well as vibrations caused by the still increasing traffic in the streets below had made the observations inaccurate.
In 1861 the observatory was moved to Østervold, where a new observatory was constructed on the old bastioned fortifications
Fortifications of Copenhagen (17th century)
The fortifications of Copenhagen underwent a comprehensive modernization and expansion in the 17th century. The project was commenced and largely masterplanned by Christian IV in the early 17th century but continued and completed by his successors...
of the city, which had become outdated and were being disabandonned. The well-known Russian-German astronomer, Heinrich Louis d'Arrest
Heinrich Louis d'Arrest
Heinrich Louis d'Arrest was a German astronomer, born in Berlin. His name is sometimes given as Heinrich Ludwig d'Arrest....
, who had been appointed professor in astronomy at the university in 1857, was chosen to plan the new observatory. He used the observatory for his study of nebula
Nebula
A nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
s, in 1867 publishing an astronomical catalog
Astronomical catalog
An astronomical catalog or catalogue is a list or tabulation of astronomical objects, typically grouped together because they share a common type, morphology, origin, means of detection, or method of discovery...
ue of 1.942 nebulas with 4.900 positions. He also did significant work in spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
, and discovered, for the first time, the differences in the evolutionary state and spatial distribution of stars. While d'Arrest used the main telescope, observer H. C. F. C. Schjellerup used the Meridian circle for creating one of the most comprehensive astronomical catalogues of the time of stars of the 8th-9th magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
: 10,000 positions on 259 observation nights.
The next director of the Østervold Observatory was Thorvald N. Thiele
Thorvald N. Thiele
Thorvald Nicolai Thiele was a Danish astronomer, actuary and mathematician, most notable for his work in statistics, interpolation and the three-body problem. He was the first to propose a mathematical theory of Brownian motion...
, a skilful mathematician who developed a new method of determining the orbit of Binary star
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
s. He founded the tradition for numerical computational mathematics, which has lasted up to modern times.
In 1907, Elis Strömgren
Elis Strömgren
Svante Elis Strömgren was a Swedish-Danish astronomer.Strömgren was born in 1870 in Helsingborg, Scania. He received his doctorate at Lund University in 1898, becoming docent there the same year. He worked at the University of Kiel from 1901, and assisted in the publication of Astronomische...
was appointed professor and director of the observatory, and under his direction the computational work continued.
During World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
, the Central Bureau for Astronomical Telegrams
Central Bureau for Astronomical Telegrams
The Central Bureau for Astronomical Telegrams is the official international clearing house for information relating to transient astronomical events....
, founded by Astronomische Gesellschaft
Astronomische Gesellschaft
The Astronomische Gesellschaft is an astronomical society established in 1863 in Heidelberg, the second oldest astronomical society after the Royal Astronomical Society....
in 1882, was moved from Kiel
Kiel
Kiel is the capital and most populous city in the northern German state of Schleswig-Holstein, with a population of 238,049 .Kiel is approximately north of Hamburg. Due to its geographic location in the north of Germany, the southeast of the Jutland peninsula, and the southwestern shore of the...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, to the Østervold Observatory. It remained located in Copenhagen until 1965, when it was moved to the Smithsonian Astrophysical Observatory
Smithsonian Astrophysical Observatory
The Smithsonian Astrophysical Observatory is a research institute of the Smithsonian Institution headquartered in Cambridge, Massachusetts, where it is joined with the Harvard College Observatory to form the Harvard-Smithsonian Center for Astrophysics .-History:The SAO was founded in 1890 by...
, Cambridge
Cambridge
The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...
, USA.
In 1940 Ellis Strömgren was succeeded by his son Bengt Strömgren
Bengt Strömgren
Bengt Georg Daniel Strömgren was a Danish astronomer and astrophysicist.Bengt Strömgren was born in Gothenburg. His parents were Hedvig Strömgren and Svante Elis Strömgren, who was professor of astronomy at the University of Copenhagen and director of the University Observatory in Copenhagen...
. He made the pioneering discovery that hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
is the most abundant element in the stellar interior
Stellar structure
Stars of different mass and age have varying internal structures. Stellar structure models describe the internal structure of a star in detail and make detailed predictions about the luminosity, the color and the future evolution of the star....
, and he was the first to make the correct interpretation of the Hertzsprung–Russell diagram
Hertzsprung–Russell diagram
The Hertzsprung–Russell diagram is a scatter graph of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their spectral types or classifications and effective temperatures. Hertzsprung–Russell diagrams are not pictures or maps of the locations of the stars...
(the relation between the total energy output from a star and its surface temperature was independently found by the Danish chemist and astronomer Ejnar Hertzsprung
Ejnar Hertzsprung
Ejnar Hertzsprung was a Danish chemist and astronomer.Hertzsprung was born in Copenhagen. In the period 1911–1913, together with Henry Norris Russell, he developed the Hertzsprung–Russell diagram....
and the American astronomer Henry Norris Russell
Henry Norris Russell
Henry Norris Russell was an American astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung–Russell diagram . In 1923, working with Frederick Saunders, he developed Russell–Saunders coupling which is also known as LS coupling.-Biography:Russell was born in 1877 in Oyster Bay, New...
). Around 1950, he developed the UVBYß photoelectric system, which is still in use today.
In the 1950s, the Østervold Observatory was replaced by the Brorfelde Observatory
Brorfelde Observatory
Brorfelde Observatory is an astronomical observatory home to the Brorfelde Schmidt Telescope. It was run as a branch of the Copenhagen University Observatory until 1996. It still has telescopes that are used by University of Copenhagen students, but the staff that manned them moved to the...
located near the town of Holbæk, it was provided with a very fine meridian circle and a Schmidt camera. It houses a 300 double reflector
Refracting telescope
A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...
with a focal depth of 4.9 m.
Building
The Østervold Observatory is a south-facing, three-winged building, designed by Christian HansenChristian Hansen (architect)
Hans Christian Hansen was a Historicist Danish architect who worked 18 years in Greece where he was active in the transformation of Athens from a small town to the country's capital and an international metropolis...
. The central wing is topped by a dome
Dome
A dome is a structural element of architecture that resembles the hollow upper half of a sphere. Dome structures made of various materials have a long architectural lineage extending into prehistory....
. containing the main instrument. The side wings contained residences for the director, the observer as well as assistants. To secure the best possible foundation of the instruments, the foundation of the building rests on the original, true ground surface, penetrating the entire depth of the ramparts on which the building stands. This took 1/3 of the bricks used for the entire complex.
Instruments
The proginal main instrument of the observatory, housed in the dome, was a 280 mm reflector with a foval depth of 4.9 m. In 1895, this telescope was replaced by a 300 mm double reflector with a focal depth of 4.9 m and a 200 mm photographic lens with a focal depth of 4.8 m. The purchase of the double reflector enabled the observatory to participate in photographic observations without having to give up visual observations. This double reflector is still found in the dome of the Østervold Observatory, while the 1861 reflector is displayed at the Steno Museum in Århus.Directors
1862-1875: Heinrich Louis d'ArrestHeinrich Louis d'Arrest
Heinrich Louis d'Arrest was a German astronomer, born in Berlin. His name is sometimes given as Heinrich Ludwig d'Arrest....
1875-1907: Thorvald N. Thiele
Thorvald N. Thiele
Thorvald Nicolai Thiele was a Danish astronomer, actuary and mathematician, most notable for his work in statistics, interpolation and the three-body problem. He was the first to propose a mathematical theory of Brownian motion...
1907-1940: Elis Strömgren
Elis Strömgren
Svante Elis Strömgren was a Swedish-Danish astronomer.Strömgren was born in 1870 in Helsingborg, Scania. He received his doctorate at Lund University in 1898, becoming docent there the same year. He worked at the University of Kiel from 1901, and assisted in the publication of Astronomische...
1940-1951. Bengt Strömgren
Bengt Strömgren
Bengt Georg Daniel Strömgren was a Danish astronomer and astrophysicist.Bengt Strömgren was born in Gothenburg. His parents were Hedvig Strömgren and Svante Elis Strömgren, who was professor of astronomy at the University of Copenhagen and director of the University Observatory in Copenhagen...