Title: Ira Sprague Bowen Papers,
Date (inclusive): 1940-1973
Bowen, Ira Sprague
Extent: Approximately 29,000 pieces in 88 boxes
San Marino, California 91108
Placed on permanent deposit in the Huntington Library by the Observatories of the
Carnegie Institution of Washington Collection. This was done in 1989 as part of a letter
of agreement (dated November 5, 1987) between the Huntington and the Carnegie
Observatories. The papers have yet to be officially accessioned. Cataloging of the papers
was completed in 1989 prior to their transfer to the Huntington.
There is no evidence that Bowen 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.
Collection is open to qualified researches by prior application through the Reader
Services Department. For more information please go to following
In order to quote from, publish, or reproduce any of the manuscripts or visual materials,
researchers must obtain formal permission from the office of the Library Director. In
most instances, permission is given by the Huntington as owner of the physical property
rights only, and researchers must also obtain permission from the holder of the literary
rights In some instances, the Huntington owns the literary rights, as well as the
physical property rights. Researchers may contact the appropriate curator for further
[Identification of item], Ira Sprague Bowen Papers, The Huntington Library, San Marino,
Ira Sprague Bowen, a physicist by training, was the third director of the Mount Wilson
Observatory. As director, he led the Observatory through its biggest transition since its
founding in 1904: its joint operation of the largest telescope in the world, the 200-inch
Hale Telescope, with the California Institute of Technology. Even though his formal
scientific output fell off as director, his position of responsibility for the Mount
Wilson and Palomar Observatories marks him as a very important figure in the history of
Ira Bowen was born on December 21, 1898, in Seneca Falls, New York. His father, James H.
Bowen, was pastor of the local Wesleyan Methodist Church. His mother, Philinda Sprague
Bowen, was a licensed teacher in New York State. In 1900, the family moved to Millview,
Pennsylvania, and five years later James Bowen became business agent of the Wesleyan
Methodist Church. This latter position resulted in the family moving around quite a bit
when Ira Bowen was still very young, and he was educated at home until 1908. In 1908,
James Bowen died, and Ira entered the Houghton Wesleyan Methodist Seminary where his
mother had become a teacher.
Ira Bowen's interest in science grew during his stay at Houghton where he became adept at
devising many experimental arrangements with the limited resources of the school and his
family. He stayed on to attend the junior college at the seminary and he was placed in
charge of the high school physics laboratory. After three years of college courses at
Houghton, Bowen transferred to Oberlin College for his senior year, receiving his A.B.
degree in 1919.
Bowen's aptitude for research was quickly recognized and in the fall of 1919 he was given
a scholarship and began to pursue his graduate studies at the University of Chicago. He
soon took the vacant position as laboratory assistant to the eminent physicist Robert A.
Millikan, a figure who became a tremendous influence on Bowen. Under Millikan, Bowen
gained expertise in spectroscopy and atomic physics.
In 1921, Millikan was tempted by George Ellery Hale to transfer to the new California
Institute of Technology (Caltech). Bowen accompanied Millikan and became a lecturer in
the physics department while assisting Millikan in his cosmic-ray research. In addition,
Bowen also found time to continue his own atomic physics research, especially in the
fields of vacuum ultraviolet and x-ray spectroscopy.
Bowen did not obtain his Ph.D. degree until 1926, mainly because of his heavy research
and teaching load. The future importance of the degree finally caused him to take it with
a thesis on a project alien to his main interests. While guiding a student on a project
dealing with evaporation, the student lost interest, but Bowen maintained his own
excitement and completed the research. Since he was working on the evaporation project
when he decided to take his degree, he used this research, "The Ratio of Heat Losses by
Conduction and by Evaporation from Any Water Surface," as his thesis.
Bowen's entry into the astrophysical world came when he read about the dilemma of the
"nebulium" lines. Since the 1860's astronomers had been unable to identify many of the
emission lines in the spectra of galactic nebulae. As a result they postulated the
existence of an element, "nebulium," unknown on earth, which produced the mysterious
spectral lines. For various reasons, the nebulium explanation was unsatisfactory and
astronomers continued to search for a better answer. In 1927, after reading a possible
explanation advanced by Henry Norris Russell, Bowen realized that the nebulium lines
could be explained by electron transitions that were only possible in a rarefied gas. The
nebulium lines would never have been observed on earth since no gas was rarefied enough
to prevent electron collisions from interfering with the infrequent transitions which
produced the lines. Since Bowen had the necessary spectroscopic data on hand from his
earlier research, he quickly calculated the wavelengths of the spectral lines of these
"forbidden" transitions of various light elements. After obtaining the wavelengths, he
compared them to those of the nebulium lines and saw that they were indeed the same.
Bowen's reputation in astrophysics was made and he now had a new field in which to turn
his tireless research activities.
It was during this new burst of activity that Bowen married Mary Jane Howard in 1929. No
personal letters exist in this collection, but that is not surprising since they were
very rarely separated. Mary Bowen's position as a child psychologist often prevented her
from going with Ira on his journeys to Washington, D.C. for Carnegie Institution of
Washington (CIW) meetings or other astronomical council meetings, but these trips were of
short duration. They had no children.
Although Bowen continued with his laboratory spectroscopy and cosmic-ray work, he fell
deeper into astrophysics. Collaborations with William Hammond Wright at the Lick
Observatory led to his appointment in 1938 as Morrison Research Associate. During his
summer at Lick, he worked with Arthur B. Wyse on the study of the spectra of galactic
nebulae. Due to the difficulty of taking spectra of the faint nebulae, Bowen developed
the "image slicer," a device that essentially enabled more of the light of the target
nebula to enter the narrow spectrograph slit. This keen aptitude for instrumentation and
optics would prove invaluable in the development of observational astronomy.
Bowen soon got a chance to apply his expert knowledge of optics when he was placed on the
Policy Committee of the 200-inch telescope. The 200-inch project got underway in 1928
when George Ellery Hale obtained funding from the Rockefeller Foundation to build the
world's largest telescope. During the 1930s Bowen played an important part in many of the
design decisions for this enormous undertaking. He did not realize that he would
eventually be the central figure in the telescope's completion.
His involvement with the 200-inch telescope had to be put aside during the Second World
War. As did most scientists, Bowen joined the war effort by signing on with the Caltech
ordnance rocket project, where he found himself working alongside many of the Mount
Wilson astronomers. Until 1945, he helped in the research on all aspects of rocketry as
well as producing a high-speed camera and taking part in studies on the transparency of
seawater. He was also appointed a project supervisor of several Office of Scientific
Research and Development contracts on the West Coast. One of these was the contract that
involved the Mt. Wilson Observatory in war work.
The turning point in Bowen's career came in July, 1945, as the War was coming to an end.
Vannevar Bush, head of the Office of Scientific Research and Development and president of
the CIW, informed Bowen that he had been chosen to be the new director of the CIW's Mount
Wilson Observatory. The Observatory's second director, Walter Sydney Adams, was retiring
on January 1, 1946, and in the discussions concerning his successor, Bowen's name had
come up practically from the start. His familiarity with the Mount Wilson staff and his
optical/instrumental expertise made him an obvious choice as director. Bowen soon
accepted the offer and began to make the transition from researcher to administrator.
Bowen's main task as director was the completion of the 200-inch telescope to be placed
on Palomar Mountain. The funding for the telescope had been given to Caltech, but they
did not have the staff to operate the Palomar Observatory. The decision was made that the
Mount Wilson Observatory would operate the Palomar Observatory as well, but under the
joint administration of Caltech and CIW. As director, Bowen would have to deal
effectively with both CIW and Caltech, a job he performed exceedingly well during his
eighteen-year tenure. In 1946, when he came on board as Observatory director, the
200-inch was four years away from completion. With most of the original designers retired
or ill, Bowen, with the able assistance of Bruce H. Rule, took personal charge of the
final stages of the project. In addition, he oversaw the staffing and organization of the
Palomar Observatory. Realizing the magnitude of the project, Bowen took little time out
for other affairs until the 200-inch mirror had been polished and figured. He personally
analyzed the optical tests of the mirror. The 200-inch telescope was dedicated in June
1948 as the Hale Telescope, but Bowen continued to concentrate on the mirror until the
telescope was placed into regular service in 1949.
With the dedication of the 200-inch Hale Telescope in 1948, the Mount Wilson Observatory
became the Mount Wilson and Palomar Observatories [MWPO]. Along with the 60-inch and
100-inch telescopes on Mount Wilson, Bowen was in charge of the most awesome telescopic
array in the world. Understanding that many astronomers, especially those on the American
East Coast and Europe, had rare access to instruments such as those at MWPO, he developed
the guest investigator program. Although he could not meet the needs of all astronomers,
the guest investigator program helped enrich many research programs before the existence
of "national observatories."
Joining the excellent instruments of the MWPO was the new 48-inch Schmidt telescope on
Palomar. This telescope, with its extremely wide field of view and high speed, would open
a new vista for astronomical research. Bowen knew that the best initial use for the
Schmidt telescope was a photographic survey of the entire sky visible from Palomar.
Funding for this massive project was provided by the National Geographic Society and it
got underway in 1949. Supervised by Rudolph Minkowski, and photographed by Albert G.
Wilson and George O. Abell, the National Geographic Society-Palomar Sky Survey consisted
of approximately 2000 photographic plates. These plates would be copied and then sold at
cost to any astronomical institution desiring a set. Completed in 1957, the Sky Survey
has proven to be an essential tool in the study of all facets of astronomy.
The period when Bowen was director was a time of great change for science. New funding
structures were put into place for "big science" with the continued interest of the
military and the new National Science Foundation. Bowen's advice was sought out by many
to aid in the establishment of post-war institutions and research. His expertise in
optics also made him a great resource for those designing the latest telescopes. Among
these were Vannevar Bush, Theodore Dunham, Jr., and Robert R. McMath. The latter found
Bowen's counsel invaluable for the development of AURA, Inc., and the Kitt Peak National
Bowen's directorship ended in 1964, at the mandatory retirement age of 65. Nevertheless,
he continued his close relationship with the Observatory as Distinguished Service Staff
Member, Carnegie Institution of Washington. In this capacity he helped develop innovative
optical designs on three new telescopes, the 60-inch at Palomar, the 40-inch Swope
Telescope, and the 100-inch Irenie DuPont Telescope, the latter two at Las Campanas. He
was also highly sought after as an optical consultant for the development of the new
large telescopes which were springing up all over the world, to the point of even being
offered a senior professorship at the University of Arizona.
Throughout his career, Bowen was recognized as an important contributor to science. His
peers conferred many awards on him including the Draper Medal (National Academy of
Sciences, 1942), the Rumford Premium (American Academy of Arts and Sciences, 1949), the
Ives Medal (Optical Society of America, 1952), the Bruce Gold Medal (Astronomical Society
of the Pacific, 1957), and the Gold Medal of the Royal Astronomical Society (1966).
Bowen's life ended suddenly on February 6, 1973, while he was working on designs of the
DuPont Telescope. To describe Ira Bowen, it would be best to rely on the testimony of his
close associates. Jesse Greenstein, chairman of Caltech's astronomy department during
Bowen's tenure at MWPO found it "hard to communicate his personal charm. He was a modest
and reserved man at all times, 'Ike' to everyone. He had many of the virtues of the past
generation that built science in the United States. His background, his long, happy
marriage to Mary Jane Howard, his love of the outdoors, small animals, photography,
hiking in the mountains, his personal and scientific economy lent him assurance and
gentleness." And his long-time associate at MWPO, Olin Wilson, said of Bowen that he "was
a rather reserved individual whom many people found difficult to know well. His great
enthusiasm for his work is shown by his many accomplishments, yet it never appeared on
the surface as exuberance. His great strength lay in careful, logical thinking through of
problems before arriving at solutions. Consequently, everything he designed worked
exactly as he said it would. There can be no question that he is one of the major figures
in the astronomy of the 20th century."