Famous research done at Yerkes Observatory.

A listing of all the research ever done at a major observatory would encompass many volumes; the following provides a representative sample of important work at Yerkes Observatory during the last century.

Many famous astronomers who have worked at Yerkes Observatory went on to be Bruce Medalists.

Edward E. Barnard suggested that the dark areas in the Milky Way are caused by opaque interstellar dust which conceal large numbers of stars; his photographic atlas of the Milky Way is a classic work.

Sherburne W. Burnham used the 40-inch Refractor to measure orbits of stars around each other, providing fundamental knowledge of stellar masses.

Otto Struve made major contributions in the field of stellar spectroscopy, using a spectroscope attached to a telescope to determine the chemical nature and other properties of stars. He also discovered widespread interstellar clouds of very tenuous gas in the plane of the Milky Way Galaxy.

Bengt Stromgren added greatly to our understanding of such interstellar gas clouds, especially those surrounding very hot stars. In addition, he pioneered work on the physical nature of stars.

Gerard Kuiper is best known for his discoveries and theories about the solar system. Kuiper discovered carbon dioxide in the atmosphere of Mars; he also discovered the fifth moon of Uranus, and the second moon of Neptune. He was also instrumental in the development of infrared astronomy; he was motivated by his planetary studies.

W. Albert Hiltner discovered that interstellar dust particles cause a slight polarization of starlight, which can be used to understand better the particles and their environment, as well as mapping the magnetic field in the Milky Way.

Subrahmanyan Chandrasekhar studied the behavior of dying stars called white dwarfs, which led to an understanding of the maximum mass such stars can have (now known as "The Chandrasekhar Limit"). He won the Nobel Prize in Physics in 1983 for his theoretical studies of the physical processes concerning the structure and evolution of stars.

William W. Morgan established precise classification systems for the spectra of stars and the forms of galaxies. He significantly improved methods used to determine stellar distances and demonstrated the existence of supergiant galaxies. With data obtained with the 40-inch Refractor between 1937 and 1951, Morgan deduced the spiral nature of the Milky Way Galaxy. Morgan published several spectroscopic atlases, including the Revised MK Atlas for Stars Earlier than the Sun, in 1978, a classic work of stellar spectroscopy. One of the instruments he used appears on the exhibits page.

George Ellery Hale invented a spectroheliograph when he was a student at MIT, before Yerkes Observatory even existed. Hale brought the spectroheliograph with him when he came to Yerkes, and it was used for solar observations on the 40-inch Refractor from the 1890s to the 1930s.

Frank Schlesinger, working here in 1903, used the 40-inch refractor to develop the techniques used here and everywhere else for fundamental photographic measurement of stellar distances (parallaxes) for the next 6-7 decades. A large fraction of the telescope's time was devoted to such measurements up until the parallax program was phased out in the early 1990's. In the 1980's higher precision in such measurements were attained here than in any other routine parallax program, largely because of the telescope's quality, as well as the improved techniques that were developed here and elsewhere in the 1970's.

The Astrophysical Journal was founded at Yerkes by Hale and James Keeler in 1895, and it is even still an important journal in astrophysics -- as well as still published by the University of Chicago Press. For a nice article on the history of ApJ, see this article, by Donald Osterbrock.

Go back to the history page, or continue on to learn about some of the research being done at Yerkes today.

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Content originally generated in March 1995.
This file was last modified on 20 April 1999.