Jean Abraham Chrétien Oudemans (

Amsterdam Amsterdam ( , , , lit. ''The Dam on the River Amstel'') is the Capital of the Netherlands, capital and Municipalities of the Netherlands, most populous city of the Netherlands, with The Hague being the seat of government. It has a population ...

, 16 December 1827 –

Utrecht Utrecht ( , , ) is the List of cities in the Netherlands by province, fourth-largest city and a List of municipalities of the Netherlands, municipality of the Netherlands, capital and most populous city of the Provinces of the Netherlands, pro ...

, 14 December 1906) was a Dutch

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

. He was the director of the

Utrecht Observatory Sonnenborgh Observatory ( nl, Museum Sterrenwacht Sonnenborgh; Sonnenborgh museum & sterrenwacht; obs. code: 015) is an astronomical observatory and museum open to the public, located in Utrecht, Netherlands. It was founded in 1853 as a u ...

from 1875 until 1898, when he retired. Oudemans was born in Amsterdam, son of the poet, teacher and philologist Anthonie Oudemans Sr. and Jacoba Adriana Hammecker. He entered

Leiden University Leiden University (abbreviated as ''LEI''; nl, Universiteit Leiden) is a Public university, public research university in Leiden, Netherlands. The university was founded as a Protestant university in 1575 by William the Silent, William, Prince o ...

when he was just 16 as a student of the noted astronomer

Frederik Kaiser Frederik Kaiser (Amsterdam, 10 June 1808 – Leiden, 28 July 1872) was a Dutch astronomer. He was director of the Leiden Observatory from 1838 until his death. He is credited with the advancement of Dutch astronomy through his scientific c ...

. He became a high school teacher in

Leiden Leiden (; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 119,713, but the city forms one densely connected agglomeration wit ...

when he was just 19 (1846). The next six years he worked on his dissertation on the determination of the latitude of Leiden. Next he studied

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

s and

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

s, meanwhile hoping for an academic appointment. In 1855 he became member of the

Royal Netherlands Academy of Arts and Sciences The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed ...

. He married Pauline Adriana Verdam (the daughter of a well-known mathematics professor Gideon Jan Verdam ) in 1856. In the same year he was appointed a

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...

Utrecht University Utrecht University (UU; nl, Universiteit Utrecht, formerly ''Rijksuniversiteit Utrecht'') is a public research university in Utrecht, Netherlands. Established , it is one of the oldest universities in the Netherlands. In 2018, it had an enrollme ...

and became the first director of its

observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. His ...

. However, his interest drew him towards

geography Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...

. He traveled to the

Dutch East Indies The Dutch East Indies, also known as the Netherlands East Indies ( nl, Nederlands(ch)-Indië; ), was a Dutch colony consisting of what is now Indonesia. It was formed from the nationalised trading posts of the Dutch East India Company, which ...

as head

surveyor Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...

, and worked in that capacity for 18 years, publishing his works on the

triangulation In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle me ...

of the island of

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

in six books. In 1874 he organized an astronomical expedition to the island of

Réunion Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island ...

to observe the

transit of Venus frameless, upright=0.5 A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against (and hence obscuring a small portion of) the solar disk. During a trans ...

but, due to bad weather, the results were disappointing. Oudemans

crater Crater may refer to: Landforms *Impact crater, a depression caused by two celestial bodies impacting each other, such as a meteorite hitting a planet *Explosion crater, a hole formed in the ground produced by an explosion near or below the surfac ...

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

was named in his honor. A brother was the botanist

Corneille Antoine Jean Abram Oudemans Corneille Antoine Jean Abram Oudemans or Cornelis Antoon Jan Abraham Oudemans (7 December 1825 – 29 August 1906) was a Dutch botanist and physician who specialized in fungal systematics. Oudemans was born in Amsterdam, the oldest of seven child ...

. One of his sons was Anthonie Cornelis Oudemans Jzn, one of the fathers of

cryptozoology Cryptozoology is a pseudoscience and subculture that searches for and studies unknown, legendary, or extinct animals whose present existence is disputed or unsubstantiated, particularly those popular in folklore, such as Bigfoot, the Loch Ness ...

References

Sources

* (1989) ''Empire of Reason: Exact Sciences in Indonesia, 1840-1940'', Brill, , , pp. 20–98 {{DEFAULTSORT:Oudemans, Jean Abraham Chretien 1827 births 1906 deaths 19th-century Dutch astronomers Dutch surveyors Members of the Royal Netherlands Academy of Arts and Sciences Members of the French Academy of Sciences Scientists from Amsterdam Leiden University alumni Utrecht University faculty