The Lake County Astronomical Society

Astronomy Bio...Adriaan Van Maanen

Jay Bitterman

Adriaan Van Maanen was a Dutch-born American astronomer born in Sneek, The Netherlands, on March 31, 1884.

He was of aristocratic parentage, his father being John William Gerbrand and his mother Catharina Visser Van Maanen. He was educated at the University of Utrecht, where he earned his BA in 1906, his MA in 1909 and his Ph.D. two years later. His first position was at the University of Groningen.

Van Maanen's career began at a particularly fortunate time, when technical knowledge was advancing at a tremendous rate, which allowed him to use the latest developments in telescope design for his observations.

In 1911 he left the Netherlands to join the staff of the Yerkes Observatory near Chicago. Yerkes Observatory had only recently been completed when the young Van Maanen went to work there as a volunteer in an unpaid capacity to gain experience in astronomy.

By 1912 he attained a position at the Mount Wilson Observatory, where he was mostly involved with the measurement of the proper motions and parallaxes of stars. He used the new 60-inch reflector for his work.

Most of his working life was devoted to studying the motion of planetary nebulae and faint stars. At one time he was also involved with the measurement of the solar magnetic field. His findings were somewhat inaccurate due to the available equipment, but the measurements were not improved upon until the early 1950's when more sophisticated technology was available.

When new technology became available at the Mount Wilson Observatory, that gradually included bigger and better mirrors, Van Maanen was able to exploit the potential of this more sophisticated equipment. He could study the motion of planetary nebulae and faint stars. His observations on the rate of rotation of some nebulous spirals was also a stimulus to Harlow Shapely (1885-1972) in his argument for the possibility of "Island Universes".

He carried out a full program of research, observation and photography during his career and his meticulous measurements formed the basis for future investigation by Astronomers. He passed away in 1946.