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Clyde W. Tombaugh, 1906-1997


black and white portrait of Clyde Tombaugh looking through telescope


Clyde W. Tombaugh is best known for his February 18, 1930, discovery of Pluto, at Lowell Observatory in Arizona. The majority of his career was spent in New Mexico, working first on the tracking telescopes at White Sands Proving Ground and later helping to establish the astronomy program at New Mexico State University in Las Cruces, considered one of the nation’s best. After his retirement in 1973, Dr. Tombaugh remained very active as a lecturer. Many senior Library staff members remember interacting with him on a regular basis as he came and went from his office in the astronomy department, located just across the street from the Library. Born in Illinois in 1906, the world-famous astronomer passed away on January 17, 1997, at the age of ninety.

Biographical Outline

1906 Feb. 4: Clyde William Tombaugh was born on a farm near Streator, Illinois
1922 The family moved to a Kansas farm
1925 Graduated from Burdett High School, Burdett, Kansas
1926 Constructed the first telescope
1927-1928 Constructed 9-inch telescope
1929 After sending planetary sketches to Lowell Observatory in Flagstaff, Arizona, hired by Observatory Director V. M. Slipher to conduct planet-search photography
1930 Feb. 18: Discovered ninth planet Pluto by comparing (“blinking”) photographic plates
  Mar.13: Official announcement of the discovery
1931 Awarded the Jackson-Gwilt Medal and Gift by the Royal Astronomical Society in recognition of his discovery. Also received the Edwin Emory Slosson Scholarship to the University of Kansas, Lawrence, Kansas
1932 Entered the University of Kansas as a freshman; continued planet search work at Lowell Observatory in the summers while pursuing his university education
1934 Married Patricia (Patsy) Edson (two children: Annette, born 1940, and Alden, born 1945)
1936 B.A., University of Kansas
1939 M.A., University of Kansas. Thesis: “Study of the Observational Capabilities of the University’s 27-inch Newtonian Reflector with a Program to Restore the Telescope to Pristine Condition”
1943-1945 Taught at Arizona State Teachers College (now Northern Arizona University) in Flagstaff, serving first as a physics instructor for the college and later as a navigation instructor for the Navy V-12 program
1945   End of the Trans-Saturnian Planet Search at Lowell Observatory. In addition to identifying the ninth planet Pluto, during the course of the planet search Tombaugh discovered numerous star clusters and clusters of galaxies, hundreds of asteroids, two comets, and one nova, and showed the full extent of the Great Perseus-Andromeda Stratum of Extra-Galactic Nebulae
1945-1946 Visiting Assistant Professor in Astronomy at the University of California at Los Angeles
1946 Moved to Las Cruces, New Mexico
1946-1950 As Chief of Optical Measurements Section at White Sands Proving Ground was responsible for the tracking telescopes used to photograph rockets and missiles during test flights
1950-1955 Optical physicist in charge of optical and photographic research in the Systems Engineering Branch at White Sands Proving Ground
1951 Founded Las Cruces Astronomical Society with Jed Durrenberger, Walter Haas, and others, and served as its first president
1952 Returns to Lowell Observatory for a few months to conduct preliminary work on a proposed survey of the proper motion of stars
1953-1955 Initiated and led Near Earth Satellite Search, funded by the Army Office of Ordnance Research and conducted at Lowell Observatory. The search was focused on identifying any small natural satellites of the Earth as a preparatory step to beginning space exploration
1955 Administration of the satellite search project transferred from White Sands Proving Ground to the Physical Science Laboratory at New Mexico State University (NMSU)
1955 Clyde and Patsy Tombaugh are among the founding members of the Las Cruces Unitarian Fellowship (now Unitarian Universalist Church of Las Cruces)
1956-1958 Satellite search project was conducted in Quito, Ecuador; the search was extended beyond the original end date of 1957 in order to photograph the first man-made satellite Sputnik I
1958-1973 Initiated and led photographic Planetary Patrol of Mercury, Venus, Mars, Jupiter, and Saturn
1959 Near Earth Satellite Search final report issued; no satellites had been found. This negative result gave assurance that rockets could be sent into space without colliding with natural debris
1959-1968 Transferred from NMSU Physical Science Laboratory to the new NMSU Research Center as an associate research professor. In addition to the planetary patrol work, Tombaugh carried out projects studying the geology of Mars and conducted a site evaluation study for a proposed Air Force observatory near Cloudcroft, New Mexico
1960 Received honorary doctorate from Northern Arizona University, Flagstaff, Arizona
1961-1970 Taught astronomy half-time in the Department of Earth Sciences (renamed Department of Earth Sciences and Astronomy in 1965), continued research work in NMSU Research Center half-time
1968   Work to establish an Astronomy graduate program at NMSU moves forward with the submission of a “Request for Preliminary Accreditation for a Degree of Doctor of Philosophy in Astronomy”
1970 July 1: Ph.D. granting Department of Astronomy established at New Mexico State University
1972 Dedication of the Clyde W. Tombaugh Observatory on the New Mexico State University campus
1973 Retired from New Mexico State University as Emeritus Professor of Astronomy
1980     Out of the Darkness, The Planet Pluto, an autobiographical account of the discovery published with co-author Patrick Moore. Numerous events were held to commemorate the fiftieth anniversary of the discovery of Pluto, including the meeting “Pluto – The Ninth Planet’s Golden Year” sponsored by the NMSU Department of Astronomy.
1986 Clyde Tombaugh Scholars Fund in support of a postdoctoral fellowship at New Mexico State University established
1987-1988 Conducted a national speaking tour to raise funds for Tombaugh Scholars Fund
1997 Jan. 17: Died at his home near Las Cruces, New Mexico

About the Collection

“Space science, space industry and astronomy have long been a part of the history of the Southwest, and especially of southwestern New Mexico. The personal papers of men such as yourself, then, are as natural and logical a part of a collection on the Southwest as are records dealing with Billy the Kid and agriculture.”
Dennis Rowley, NMSU Archivist in letter to Clyde Tombaugh, 1972

Personal and professional papers of the planetary astronomer who discovered Pluto in 1930. Consisting of approximately 150 linear feet of material, the papers include correspondence, educational records, administrative files, research files, writings, technical drawings, photographs, astronomical charts, and printed matter.

Personal papers document Tombaugh’s Kansas boyhood, his early interest in astronomy and telescope-making, and his arrival at Lowell Observatory, Flagstaff, Arizona, in 1929. Later materials concern his diverse interests in politics, education, religion, and his family life.

The extensive professional papers span Tombaugh’s full career, from his observational work at Lowell Observatory (1929-1943) to his tenure at New Mexico State University (NMSU). Tombaugh’s employment at White Sands Proving Ground (1946-1955) in New Mexico and his research in telescopic optics are well represented. The Near Earth Satellite Search, a study initiated by Tombaugh at White Sands and continued during his subsequent employment at NMSU is thoroughly documented. The bulk of his professional papers concerns his years at NMSU (1955-1973) and his work with the Planetary Patrol and Study Project. The records also illustrate the development of the NMSU Department of Astronomy. Correspondence with prominent professional and amateur astronomers, astrophysicists, and experts in related sciences is found throughout the collection, as are such visual materials as drawings, photographs, and maps.

NMSU Department of Astronomy: Clyde W. Tombaugh Papers

Finding Aid for the Clyde W. Tombaugh Collection