Karl Nikolaus Adalbert Krueger (9 December 1832 – 21 April 1896) was a German
astronomer
An astronomer is a scientist in the field of astronomy who focuses on a specific question or field outside the scope of Earth. Astronomers observe astronomical objects, such as stars, planets, natural satellite, moons, comets and galaxy, galax ...
. Born in
Marienburg,
Prussia
Prussia (; ; Old Prussian: ''Prūsija'') was a Germans, German state centred on the North European Plain that originated from the 1525 secularization of the Prussia (region), Prussian part of the State of the Teutonic Order. For centuries, ...
(now Malbork,
Poland
Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...
), he was editor of ''
Astronomische Nachrichten ''from 1881 until his death.
Krueger died of a heart condition in
Kiel
Kiel ( ; ) is the capital and most populous city in the northern Germany, German state of Schleswig-Holstein. With a population of around 250,000, it is Germany's largest city on the Baltic Sea. It is located on the Kieler Förde inlet of the Ba ...
at the age of 63.
Life and work
In 1851, Krueger entered the University of Berlin where he studied mathematics and science. In 1853, showing a special preference for astronomical studies, Krueger moved to the
University of Bonn
The University of Bonn, officially the Rhenish Friedrich Wilhelm University of Bonn (), is a public research university in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the () on 18 October 1818 by Frederick Willi ...
and became an assistant to the astronomer
Friedrich Wilhelm Argelander at the Bonn Observatory. Under Argelander's supervision he produced data for the comprehensive astrometric
star catalogue
A star catalogue is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the year ...
known as the
Bonner Durchmusterung
In astronomy, Durchmusterung or Bonner Durchmusterung (BD) is an astrometric star catalogue of the whole sky, published by the Bonn Observatory in Germany from 1859 to 1863, with an extension published in Bonn in 1886. The name comes from ('run-t ...
, together with fellow student
Eduard Schönfeld . Starting in Bonn, he undertook a lifelong study of the orbit of the minor planet
Themis
In Greek mythology and religion, Themis (; ) is the goddess and personification of justice, divine order, law, and custom. She is one of the twelve Titan children of Gaia and Uranus, and the second wife of Zeus. She is associated with oracles a ...
, whose perturbations by Jupiter eventually enabled him in 1873 (while at Helsinki Observatory) to determine the mass of the latter planet. He was awarded his doctorate by the University of Bonn in August 1854 for his dissertation titled "''De ascensionibus rectis, a Flamsteedio quadrantis muralis ope observatis''".
In 1858 a
heliometer previously used by
Friedrich Winnecke came into his hands, and was successfully employed in a series of parallax determinations. Krueger was made ''
Privatdozent
''Privatdozent'' (for men) or ''Privatdozentin'' (for women), abbreviated PD, P.D. or Priv.-Doz., is an academic title conferred at some European universities, especially in German-speaking countries, to someone who holds certain formal qualifi ...
'' in the University in 1860.
In 1862 Krueger was appointed Professor of Astronomy and Director of the Helsinki Observatory, working there for 14 years. At the time of his appointment he married Maria Wilhelmina Amalia, the eldest daughter of Friedrich Argelander. While in Helsinki, Krueger carefully determined the position of the stars of the
Double Cluster
The Double Cluster, also known as Caldwell 14, consists of the open clusters NGC 869 and NGC 884 (often designated h Persei and χ (chi) Persei, respectively), which are close together in the constellation Perseus. Both visible to the ...
in
Perseus
In Greek mythology, Perseus (, ; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of the Perseid dynasty. He was, alongside Cadmus and Bellerophon, the greatest Greek hero and slayer of ...
. The large
proper motion
Proper motion is the astrometric measure of changes in the apparent places of stars or other celestial objects as they move relative to the center of mass of the Solar System. It is measured relative to the distant stars or a stable referenc ...
of the star
Groombridge 34 was first detected by him. He also performed observations of
variable star
A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...
s, several comets and minor planets, in addition to his theoretical work. After leaving Helsinki, Krueger directed the
Gotha
Gotha () is the fifth-largest city in Thuringia, Germany, west of Erfurt and east of Eisenach with a population of 44,000. The city is the capital of the district of Gotha and was also a residence of the Ernestine Wettins from 1640 until the ...
Observatory (1876-1880), succeeding the recently deceased
Peter Andreas Hansen. In Gotha he continued to record data for the
Astronomische Gesellschaft Katalog
The ''Astronomische Gesellschaft Katalog'' (AGK) is an astrometric star catalogue of the Northern hemisphere. It was published in 3 versions from 1890 until 1975, named AGK1, AGK2 and AGK3.
History
Compilation for the first version, Astronomische ...
, an astrometric star catalogue.
Krueger was appointed as Director of the Royal Prussian Observatory in Kiel in 1880. In 1881, with the approval of the
Astronomical Society (''Astronomische Gesellschaft''), Krueger became the editor of one of the foremost astronomical journals of the day, ''
Astronomische Nachrichten''; following the death of the former editor
Christian Peters the year before. Following the death of Krueger in 1896, the editorship passed to his former assistant and son-in-law
Heinrich Kreutz.
References
External links
Obituarieslisted in the
Astrophysics Data System
The SAO/NASA Astrophysics Data System (ADS) is a digital library portal for researchers on astronomy and physics, operated for NASA by the Smithsonian Astrophysical Observatory. ADS maintains three bibliographic collections containing over 15 ...
List of Adalbert Krueger's publicationsin the Astrophysics Data System
*
Obituary printed in ''Astrophysical Journal''
*
Obituary printed in ''Astronomical Journal''
{{DEFAULTSORT:Kruger, Adalbert
1832 births
1896 deaths
Astronomers from the Kingdom of Prussia
People from Malbork
Scientists from the Province of Prussia
19th-century German astronomers