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Milton La Salle Humason Papers: Finding Aid
mssHumason papers  
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Collection Details
Table of contents What's This?
  • Overview of the Collection
  • Access
  • Administrative Information
  • Biographical Note
  • Scope and Content Note
  • Arrangement
  • Indexing Terms

  • Overview of the Collection

    Title: Milton La Salle Humason Papers
    Dates (inclusive): 1930-1952
    Collection Number: mssHumason papers
    Creator: Humason, Milton L. (Milton La Salle), 1891-1972.
    Extent: Approximately 2,100 items in 5 boxes.
    Repository: The Huntington Library, Art Collections, and Botanical Gardens. Manuscripts Department
    1151 Oxford Road
    San Marino, California 91108
    Phone: (626) 405-2129
    Email: reference@huntington.org
    URL: http://www.huntington.org
    Abstract: This collection consists primarily of the correspondence, dated 1948 to 1952, of Milton La Salle Humason (1891-1972), a staff astronomer for the Mount Wilson [& Palomar] Observatories, known chiefly for his collaboration with Edwin P. Hubble in the field of observational cosmology. There are occasional personal and scientific letters but these are few compared to the correspondence with the public, received and answered by Humason in his capacity as Secretary of the Observatory.
    Language: English.


    Open to qualified researchers by prior application through the Reader Services Department. For more information, contact Reader Services.

    Administrative Information

    Publication Rights

    The Huntington Library does not require that researchers request permission to quote from or publish images of this material, nor does it charge fees for such activities. The responsibility for identifying the copyright holder, if there is one, and obtaining necessary permissions rests with the researcher.
    There is no evidence that Humason passed on his literary rights to anyone. The Carnegie Observatories, as part of the 1987 letter of agreement, have given the Huntington Library the right to provide permission to publish from the papers.

    Preferred Citation

    [Identification of item]. Milton La Salle Humason Papers, The Huntington Library, San Marino, California.


    Deposit, Observatories of the Carnegie Institution of Washington Collection, 1988.
    Approximately fifty additional separate collections form the Mount Wilson Papers of the Observatories of the Carnegie Institution of Washington and are available for research in the Huntington Library.

    Processing/Project Information

    Cataloging of the papers was completed in 1989 prior to their transfer to the Huntington.

    Biographical Note

    Milton La Salle (his middle name has also been cited as Lasell) Humason was a staff astronomer for the Mount Wilson [& Palomar] Observatories throughout his entire astronomical career. Humason is remembered chiefly for his collaboration with Edwin P. Hubble in the field of observational cosmology. Perhaps his most notable accomplishment, however, was his rise from mule-driver and janitor at Mt. Wilson to the position of astronomer with the lack of a high-school education.
    Humason was born on August 19, 1891, in Dodge Center, Minnesota. His family moved to California, and in the summer of 1905 he was taken to a summer camp on Mt. Wilson. At this time, the Mt. Wilson Observatory was not yet a year old, and there was a good deal of activity by the solar astronomers on the mountain top. Humason involved himself in this activity by quickly dropping out of high school in the fall of 1905 and within a few years becoming a mule driver. He would lead mule-powered wagons up the Mt. Wilson Toll Road carrying timber, iron, and other supplies for the construction of the telescopes and support buildings at the Observatory. It was as a mule driver that Humason met Helen Dowd, daughter of the Observatory's engineer, Merritt C. "Jerry" Dowd, in 1910. They married one year later.
    In 1910, Humason left mountain work and got a job as a foreman on a relative's ranch in La Verne, California. In 1917, however, Jerry Dowd told Humason that a janitor's job would be opening soon at Mt. Wilson Observatory. Knowing that the janitor's position at the Observatory could eventually involve duties such as relief night assistant on the telescopes, Humason took the offer. With the new 100-inch Hooker Telescope going into operation at the Observatory in 1919 and the need for more night assistants, Humason soon got to work with the telescopes. At about the same time, Hugo Benioff, a volunteer assistant at Mt. Wilson from Pomona College, showed Humason how to take photographic plates with the 10-inch astrographic camera on the mountain. Humason became so adept at this that Benioff soon recommended that Humason carry on the former's work in the fall. As Humason gained experience he also started taking plates for Harlow Shapley's observing program. And Humason used the 10-inch to look for W. H. Pickering's proposed Planet X in 1919. When Pluto was discovered in 1930, Seth Nicholson and Nicholas Mayall examined Humason's early plates and found that Pluto had been recorded on the photographs. Unfortunately for Humason, Pluto was so near the edge of the plates, and the images there were of such bad quality, that it is not surprising that Pluto was not discovered then. Humason's abilities with the telescopes on Mt. Wilson were so admired that by 1920 he was promoted from janitor to the staff of the Observatory's Stellar and Nebular Division. Humason continued his work with the 10-inch, observing clusters like M22 and also watching the Andromeda Nebula (M31) for novae. As Edwin Hubble's work on the spiral nebulae showed them to be distant galaxies, he initiated in the late 1920s a program of systematic observation of nebular redshifts. Obtaining usable spectra of the extragalactic nebulae, with their low surface brightness, would require the utmost expertise in observing skill. For this reason, it is not surprising that Humason was chosen to be Hubble's colleague. Humason developed and refined the techniques required to take exposures of up to forty hours (over several nights) with the 100-inch telescope. From the beginning of the redshift program until his retirement in 1957, Humason photographed spectra of approximately 600 galaxies. He used the 100-inch telescope to obtain these until the 200-inch Hale Telescope became available in 1949. During this time, Humason also applied his observing skill to projects on supernovae, old novae, and faint blue stars.
    On October 1, 1948, Humason was appointed Secretary of the Observatory upon Alfred H. Joy's retirement. The duties of the Secretary involved handling the Observatory's public relations. This meant reading and often answering the various letters from the general public. The letters ranged from questions from high school students to requests for photographs to oddball theories of the universe. A colleague of Humason's, Robert S. Richardson, described the job: "It was not an easy job by any means. One of his most onerous duties was answering the numerous phone calls and crank letters that came into the observatory. You have no idea of the number of people who seem to have nothing better to do than worry about whether the moon is in its orbit, or in denouncing such impostors as Newton and Einstein, and their wholly erroneous theories of gravitation (in contrast to their own entirely new rational theory). If you answer a letter of this kind, trying to explain the fallacy in their reasoning, you immediately get another one back demanding more information. Humason's policy was to answer every such letter once, but a second time --no. If you conscientiously answered them all, you would soon find that instead of working for the observatory in Pasadena, California, you were spending most of your time working for some victim of delusional insanity in Pasadena, Newfoundland." Humason remained as Secretary until his retirement in 1957.
    Humason never earned a degree until, in 1950, an honorary doctorate was conferred on him by the University of Lund in Sweden. He retired on July 1, 1957, and soon moved to Mendocino, California. While in retirement he was occasionally consulted by the astronomers at the Observatory on questions dealing with the telescopes, especially the 100-inch. He died at his home on June 18, 1972.

    Scope and Content Note

    This collection consists primarily of the correspondence of Milton La Salle Humason, a staff astronomer for the Mount Wilson [& Palomar] Observatories. There are occasional personal and scientific letters but these are very few compared to the letters from the public. The correspondence covers the years 1930-1952 (bulk 1948-1952). It contains both incoming and carbons of outgoing correspondence. The collections also includes a few press releases, newsletters, one manuscript in German, some ephemera, several black-and-white photographs and two black-and-white slides.
    Notable participants include: Ansel Adams, Robert Aitken, Loyal Aldrich, Lawrence Aller, C. T. Elvey, G. F. Fassett, George Gamow, Cecilia Gaposchkin, Warren K. Green, John C. Hogg, Edwin Powell Hubble, Wilhelminia Iwanowska, Martin Johnson, H. Spencer Jones, Egbert A. Kreiken, Wasley Krogdahl, Oliver Justin Lee, J. H. Moore, Thornton Page, Upton Sinclair, William T. Skilling, Harold C. Urey, H. L. Vanderlinden, Edwin Wald, Fletcher G. Watson, Frederick Weiss, Astronomy charted, Boston Museum of Science, California Institute of Technology, Carnegie Institution of Washington, Drake University, Grolier Society, Harvard College Observatory, Jet Propulsion Laboratory, Los Angeles Astronomical Society, Physics today, Popular astronomy, Popular mechanics, Science illustrated, and Scientific American (this is only a partial list).


    The Humason papers have been arranged, with only minor changes, according to the manner in which they had been found in the attic of the Carnegie Observatories. They are broken into six chronological groups, arranged in the boxes as follows:
    • Box 1: 1930-1947, 1948
    • Box 2: 1949
    • Box 3: 1950
    • Box 4: 1951
    • Box 5: 1952
    Within each chronological group, the correspondence is arranged in alphabetical order by correspondent.

    Indexing Terms

    The following terms have been used to index the description of this collection in the Huntington Library's Online Catalog.  


    Hubble, Edwin, 1889-1953.
    Humason, Milton L. (Milton La Salle), 1891-1972.
    Jones, H. Spencer (Harold Spencer), 1890-1960.
    Mount Wilson and Palomar Observatories -- History -- Sources.
    Mount Wilson Observatory -- History -- Sources.
    Astronomers -- Correspondence.
    Astronomical observatories -- California -- Wilson, Mount (Mountain)
    Astronomy -- 20th century.


    Black-and-white photographs -- 20th century.
    Black-and-white slides -- United States -- 20th century.
    Ephemera -- United States -- 20th century.
    Letters (correspondence) -- United States -- 20th century.
    Manuscripts -- Germany -- 20th century.
    Newsletters -- United States -- 20th century.
    Press releases -- United States -- 20th century.

    Additional Authors

    Adams, Ansel, 1902-1984.
    Aitken, Robert Grant, 1864-1951.
    Aldrich, Loyal Blaine, 1884-1965.
    Aller, Lawrence H. (Lawrence Hugh), 1913-2003.
    Elvey, C. T. (Christian Thomas), 1899-1970.
    Fassett, F. G. (Frederick Gardiner), 1901-
    Gamow, George, 1904-1968.
    Payne-Gaposchkin, Cecilia, 1900-1979.
    Green, Warren K. (Warren Kimball), 1891-
    Hogg, John C.
    Hubble, Edwin, 1889-1953.
    Iwanowska, Wilhelminia, 1905-1999.
    Johnson, Martin, 1896-1983.
    Kreiken, Egbert A.
    Krogdahl, Wasley Sven, 1919-2009.
    Lee, Oliver Justin, 1881-1964.
    Moore, J. H. (Joseph Haines), 1878-1949.
    Page, Thornton.
    Sinclair, Upton, 1878-1968.
    Skilling, William T. (William Thompson), 1866-
    Urey, Harold Clayton, 1893-1981.
    Vanderlinden, H. L. (Henri Louis), 1892-
    Wald, Edwin.
    Watson, Fletcher G. (Fletcher Guard)
    Weiss, Frederick U.
    Astronomy charted.
    Boston Museum of Science.
    California Institute of Technology.
    Carnegie Institution of Washington.
    Drake University.
    Grolier Society.
    Harvard College Observatory.
    Jet Propulsion Laboratory (U.S.)
    Los Angeles Astronomical Society.
    Popular astronomy.
    Popular Mechanics Press.
    Science illustrated.
    Scientific American, inc.