Adriaan van Maanen (March 31, 1884, Sneek – January 26, 1946, Pasadena) was a Dutch-American astronomer. Events 307 - After divorcing his wife Minervina, Constantine marries Fausta, the daughter of the retired Roman Emperor Year 1884 ( MDCCCLXXXIV) was a Leap year starting on Tuesday (link will display the full calendar of the Gregorian calendar (or a Leap year Sneek ( Snits is a Municipality and a City in the province of Friesland (Fryslân in the northern Netherlands. Events 1340 - King Edward III of England is declared King of France. Year 1946 ( MCMXLVI) was a Common year starting on Tuesday (link will display full 1946 calendar of the Gregorian calendar. Pasadena ( is a city in Los Angeles County, California, United States. The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands The United States of America —commonly referred to as the Historically Astronomy was more concerned with the classification and description of phenomena in the sky while Astrophysics attempted to explain these phenomena
Van Maanen, born into a well-to-do family in Friesland, studied astronomy at the University of Utrecht (earning his Ph. Friesland ( West Frisian: Fryslân, Dutch Friesland) is a province in the north of the Netherlands and part of the bigger region known Utrecht University ( Universiteit Utrecht in Dutch) is a University in Utrecht, The Netherlands. D. in 1911) and worked briefly at the University of Groningen. The University of Groningen (Rijksuniversiteit Groningen located in the city of Groningen, was founded in 1614. In 1911, he came to the United States to work as a volunteer in an unpaid capacity at Yerkes Observatory. Year 1911 ( MCMXI) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a Common year The United States of America —commonly referred to as the Yerkes Observatory which calls itself "the birthplace of modern astrophysics" is an astronomical observatory operated by the University of Chicago in Within a year he got a position at the Mount Wilson Observatory, where he remained active until his death in 1946. The Mount Wilson Observatory (MWO is an Astronomical observatory in Los Angeles County California.
He discovered Van Maanen's star. Van Maanen's star is a White dwarf Star. Out of the white dwarfs known it is the third closest to the Sun after Sirius B and Procyon B
He is well known for his astrometric measurements of internal motions in spiral nebulae. A spiral galaxy is a Galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the Being of the belief that nebulae were local, stellar and gaseous systems that existed in our galaxy, his measurements came to be at odds with Edwin Hubble's discovery that the Andromeda Nebula and other spiral nebulae were extragalactic objects. Edwin Powell Hubble ( November 20, 1889 – September 28, 1953) was an American astronomer. The Andromeda Galaxy (ænˈdrɒmədə also known as Messier 31, M31, or NGC 224; often referred to as the Great Andromeda The speed at which he calculated the nebulae to rotate would have had the Cepheid stars, that Hubble had used to calculate the distance to the spirals, moving at speeds faster than that of light. A Cepheid variable (pron ˈse-f(ē-id or ˈsē-f(ē-id or Cepheid is a member of a particular class of Variable stars notable for a fairly tight correlation In 1935, it was decided that since Hubble's calculations of extragalactic Cepheid distances were correct van Maanen's astrometric measurements had to be incorrect. No one has yet determined the source of van Maanen's measurement errors.