This collection chiefly consists of the administrative, scientific, and personal correspondence of astronomer and
Mount Wilson Observatory Director Walter S. Adams (1876-1956), spanning the years 1921 to 1956, and including his work during
World War II.
There is also material from Adams' retirement years and his astronomical work.
The World War II materials reflect the secret work of Adams and the Observatory staff for the
United States government to help create prisms and optics for various types of binoculars and gun sights;
the staff also assisted with aerial and naval defense and attack strategy.
Walter S. Adams (1876-1956) was one of the original staff members of the Mount Wilson Solar
Observatory when it was formed in 1904. He became assistant to George Ellery Hale in
1917 and Director of the Observatory in 1923, a position he held until his
retirement in 1946. His primary interest was the study of stellar spectra. He worked
on solar spectroscopy and co-discovered a relationship between the relative
intensities of certain spectral lines and the absolute magnitude of a star. He was
able to demonstrate that spectra could be used to determine whether a star was a
giant or a dwarf. In 1915 he began a study of the companion of Sirius and found that
despite a size only slightly larger than the Earth, the surface of the star was
brighter per unit area than the Sun and it was about as massive. Such a star later
came to be known as a white dwarf. Along with Theodore Dunham, he discovered the
strong presence of carbon dioxide in the infrared spectrum of Venus. Adams continued
his research at the Hale Solar Laboratory until his death in Pasadena, California, on May 11,
Approximately 35,000 items in 109
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