Skip to main content

Clyde W. Tombaugh Papers,

Identifier: Ms-0407

Scope and Content

The Clyde W. Tombaugh Papers serve as a rich source for the history of astronomy as well as for research into Tombaugh's professional work and his personal life. The papers provide ample documentation of Tombaugh's work in astronomy and optical design, as well as illustrating his family life and his varied interests in education, religion, and environmental issues. Included in the collection are correspondence; biographical notes and curricula vitae; writings; speeches and lectures; research files; administrative files; teaching files; technical reports; high school and university papers; financial and legal records; telescope design drawings; files related to professional and non-professional organizations; subject files; photographs; audiovisual material; and printed matter.

Tombaugh's extensive correspondence files provide an unsurpassed source for understanding him as a person, for seeing the centrality of his astronomical interests to his personal as well as his professional activities, and for providing insight into his educational, environmental, political, and religious interests. The correspondence is separated into personal and professional correspondence (and further divided by institution within the professional correspondence). Reflecting the interconnections of his personal life and his professional work, there is considerable overlap of correspondents and topics among the several sets of correspondence. Because of this overlap, the researcher is advised that correspondence from a particular individual or on a particular subject may be located in more than one set of correspondence. Significant correspondents include George Abel, Ira S. Bowen, Charles F. (Chick) Capen Jr., James Christy, Pete Domenici, Audouin Dollfus, Frank K. Edmondson, James B. Edson, Krafft A. Ehricke, Henry L. Giclas, Walter A. Haas, Dorrit Hoffleit, J. Allen Hynek, Gerard P. Kuiper, Lincoln La Paz, C. O. Lampland, Frederick C. Leonard, David H. Levy, Brian Marsden, Patrick Moore, Frederick I. Ordway III, Roger L. Putnam, Dirk Reuyl, Elizabeth Roemer, Carl Sagan, Harrison Schmitt, Glenn T. Seaborg, Harlow Shapley, E. C. Slipher, V. M. Slipher, Hyron Spinrad, Bradford A. Smith, Alan Stern, G. Harry Stine, Otto Struve, Gerard de Vaucouleurs, Wernher von Braun, Fred L. Whipple, Albert G. Wilson, Latimer J. Wilson, and Fritz Zwicky.

Tombaugh's work in planetary astronomy is well documented, both in his professional career and in his early amateur work. Although the whole of Tombaugh's career is included, the amount of material varies greatly. The majority of the Professional Papers date from Tombaugh's tenure at New Mexico State University (NMSU). Also well represented is his work at White Sands Proving Ground. The files from Lowell Observatory, and his teaching at Arizona State Teachers College and University of California at Los Angeles, are of a much more modest scope.

Specific topics that are well documented in the collection include Pluto, Mars, telescopes and optics. The discovery of Pluto is documented primarily through correspondence, both personal and professional. Additional documentation is provided by Tombaugh's numerous articles and lectures about his recollections of the discovery, as well as a modest number of handwritten notes from the planet search, copies of planet search plates, and printed matter from the time of the discovery. The original photographic plates from the planet search, including the Pluto discovery plates, and related documents are held by the Lowell Observatory Archives, in Flagstaff, Arizona. Although Tombaugh did not focus his later research on Pluto, as the planet's discoverer he did make an effort to keep current with ongoing research on the ninth planet. Correspondence, subject files, and printed matter all provide insight into the development of scientific knowledge about Pluto, evolving theories, and the recurring debate on Pluto's status as a major planet. Of particular note are the files from the conference "Pluto - The Ninth Planet's Golden Year" held at NMSU in February 1980 to commemorate the fiftieth anniversary of Tombaugh's discovery.

The planet Mars sparked Clyde Tombaugh's imagination as a young man and continued to be a primary interest for the rest of his life. Included in his papers are sketches and notes from his observations of the red planet, as well as writings, research projects, printed matter, and extensive subject files. The geology of Mars, and the question of the Martian canals, were of significant interest to Tombaugh, and his papers reflect this focus.

The problem of constructing reflecting telescopes for astronomical use occupied Tombaugh throughout his life. His work on telescopes for his own personal use, and for friends and colleagues, is well represented by design sketches, log books, and related correspondence. The "16-Inch Club" that Tombaugh formed for amateur telescope-makers who wished to obtain the materials to grind large telescope mirrors is documented in his general personal correspondence, as well as in the Telescopes and Optics subseries within the Personal Papers series. An extensive set of design drawings exist for the tracking telescopes used to photograph rockets and missiles at White Sands Proving Ground; these are supplemented by research files and technical reports.

Also found in the Tombaugh Papers are descriptions of the NMSU Department of Astronomy's first telescopes, the 12-inch Fecker and the 16-inch Rhodes telescope, and information on their acquisition for Tombaugh's research projects and their eventual transfer to the University for general research use. Tombaugh's active involvement in the design of other telescopes acquired by the Department of Astronomy and in the planning of the department's several observatories is illustrated through his correspondence, administrative files, files on the telescopes and observatories, and in the drawings and blueprints found in the oversize materials.

The collection is an excellent source for studying the development of the astronomy research program at NMSU and the formation of the academic Department of Astronomy, with particular focus on Tombaugh's involvement in both of these areas. Tombaugh's satellite search project, transferred to NMSU in 1955, can be viewed as the beginning of astronomy research at the university, and this project and later ones, particularly the planetary patrol, are amply documented in his research files. In the early 1960s as the astronomy research program became firmly established, Tombaugh was asked to begin teaching some astronomy and geology courses. These courses opened the way to the establishment of a full-fledged graduate level Department of Astronomy, and correspondence and administrative files in the NMSU subseries of the Professional Papers show the planning and development of the program.

An oral history project of Tombaugh's family, friends, and colleagues was carried out by Herbert A. Beebe to preserve personal recollections of Tombaugh and his work at Lowell Observatory, White Sands Proving Ground, and New Mexico State University. Those interviewed were Patricia Tombaugh, Reta F. Beebe, Tom Bruce, Henry Giclas, Walter Haas, Bernard McNamara, Robert Millis, Arthur Scott Murrell, Cecil Post, William L. Reitmeyer, Jimmie C. Robinson, Charles L. Seeger, Alan Stern, Bradford A. Smith, and Lou Ann Youngblood. Transcripts, as well as audiotapes, of these oral history interviews, are included in the Tombaugh Papers.


  • 1908-2000

Language of Materials


Access and Use Restrictions

This material may be examined by researchers under supervised conditions in the Search Room.

Copy Restrictions

Copyright. Limited duplication is allowed for research purposes. User is responsible for compliance with all copyright and other applicable statutes. Patricia Tombaugh retains copyright interest in her works and in the unpublished works of Clyde W. Tombaugh during her lifetime, after which time they transfer to New Mexico State University. Rights associated with materials in this collection created by parties other than Patricia and Clyde W. Tombaugh are held by the creators of such materials.

Biographical Outline

1906, Feb. 4
Clyde William Tombaugh born on a farm near Streator, Illinois
Family moved to Kansas farm
Graduated from Burdett High School, Burdett, Kansas
Constructed first telescope
Constructed 9-inch telescope
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
Official announcement of the discovery
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 University of Kansas, Lawrence, Kansas
Entered University of Kansas as a freshman; continued planet search work at Lowell Observatory in the summers while pursuing his university education
Married Patricia (Patsy) Edson (two children: Annette, born 1940 and Alden, born 1945)
B.A., University of Kansas
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"
Taught at Arizona State Teachers College (now Northern Arizona University) in Flagstaff, serving first as physics instructor for the college and later as navigation instructor for the Navy V-12 program
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, one nova, and showed the full extent of the Great Perseus-Andromeda Stratum of Extra-Galactic Nebulae
Visiting Assistant Professor in Astronomy at University of California at Los Angeles
Moved to Las Cruces, New Mexico
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
Optical physicist in charge of optical and photographic research in the Systems Engineering Branch at White Sands Proving Ground
Founded Las Cruces Astronomical Society with Jed Durrenberger, Walter Haas, and others, and served as its first president
Returned to Lowell Observatory for a few months to conduct preliminary work on a proposed survey of proper motion stars
Initiated and led Near Earth Satellite Search, funded by the Army Office of Ordnance Research and conducted at Lowell Observatory. Search was focused on identifying any small natural satellites of the Earth as a preparatory step to beginning space exploration
Administration of the satellite search project transferred from White Sands Proving Ground to the Physical Science Laboratory at New Mexico State University (NMSU)
Clyde and Patsy Tombaugh among the founding members of the Las Cruces Unitarian Fellowship (now Unitarian Universalist Church of Las Cruces)
Satellite search project conducted in Quito, Ecuador; search was extended beyond the original end date of 1957 in order to photograph the first man-made satellite Sputnik I
Initiated and led photographic Planetary Patrol of Mercury, Venus, Mars, Jupiter, and Saturn
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
Transferred from NMSU Physical Science Laboratory to new NMSU Research Center as 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
Received honorary doctorate from Northern Arizona University, Flagstaff, Arizona
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
Work to establish 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
Dedication of the Clyde W. Tombaugh Observatory on the New Mexico State University campus
Retired from New Mexico State University as Emeritus Professor of Astronomy
Out of the Darkness, The Planet Pluto, an autobiographical account of the discovery published with co-author Patrick Moore.
Numerous events 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.
Clyde Tombaugh Scholars Fund in support of postdoctoral fellowship at New Mexico State University established
Conducted national speaking tour to raise funds for Tombaugh Scholars Fund
1997, Jan. 17
Clyde W. Tombaugh died at his home near Las Cruces, New Mexico


150 linear feet, approximate


Personal and professional papers of the planetary astronomer who discovered Pluto in 1930. 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, and religion, and his family life. The extensive professional papers span Tombaugh's full career, from his observational work at Lowell to his tenure at New Mexico State University (NMSU). Tombaugh's employment at the White Sands Proving Ground (1946-1955) and his research in optics are included. 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 the professional papers concern his employment at NMSU (1955-1973) and his work with the Planetary Patrol and Study Project. 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.


Clyde W. Tombaugh agreed to donate his papers to the Archives and Special Collections in 1972. The first accession of his papers was received in 1994 when poor health led Tombaugh to close his office in the New Mexico State University Department of Astronomy. Following Tombaugh's death in 1997, additional materials were received from Patricia Tombaugh and from the Department of Astronomy. Additional material, including the Tombaugh Oral History Project, was received from Herbert A. Beebe in 2003. In all, nineteen accessions were received.
  1. RG94-147 Department of Astronomy, New Mexico State University
  2. RG97-091 Department of Astronomy, New Mexico State University
  3. RG97-124 Gift of Patricia Tombaugh
  4. RG98-069 Gift of Patricia Tombaugh
  5. RG98-151 Department of Astronomy, New Mexico State University
  6. RG99-075 Gift of Patricia Tombaugh
  7. RG99-161 Gift of Patricia Tombaugh
  8. RG2000-139 Gift of Patricia Tombaugh
  9. RG2000-155 Gift of Patricia Tombaugh
  10. RG2000-180 Gift of Patricia Tombaugh
  11. RG2000-181 Gift of Patricia Tombaugh
  12. RG2001-170 Gift of Patricia Tombaugh
  13. RG2002-073 Gift of Patricia Tombaugh
  14. RG2002-144 Gift of Patricia Tombaugh
  15. RG2003-115 Gift of Patricia Tombaugh
  16. RG2003-131 Gift of Herbert A. Beebe
  17. RG2003-137 Gift of Herbert A. Beebe
  18. RG2003-138 Gift of Patricia Tombaugh
  19. RG2003-139 Gift of Patricia Tombaugh

Related Material

Records of Tombaugh's work at Lowell Observatory, including the original photographic plates from the Lowell planet search, are held by the Lowell Observatory Archives in Flagstaff, Arizona.

The Space Astronomy Oral History Project held by the National Air and Space Museum Archives includes a 1982 oral history interview with Tombaugh conducted by David H. DeVorkin. A transcript of this oral history interview is also available in the Clyde W. Tombaugh Papers at NMSU.

Numerous related items are held by the Niels Bohr Library at the Center for the History of Physics, American Institute of Physics. These include a 1969 oral history interview of Tombaugh; unedited footage used by Thomas Hockey in compiling his videorecording "Clyde Tombaugh and the Discovery of Pluto;" an audiorecording of Tombaugh's "Recollections of Astronomy in 1920's and 1930's" presented at a 1974 American Astronomical Society meeting; and biographical information including Tombaugh's response to the Center for the History of Physics' History of Modern Astrophysics Survey.

The New Mexico Museum of Space History in Alamogordo holds an oral history interview with Clyde Tombaugh conducted in 1986.

Related materials in the Archives and Special Collections Department of the NMSU Library include:

NMSU Department of Astronomy records (A73-49, A73-72) Oral history interviews of Clyde W. Tombaugh (UA86-005, UA87-033, UA88-047, UA94-033) Materials related to the fiftieth anniversary of the discovery of Pluto (UA80-009, UA80-041, UA80-051, RG99-095) Video "The Ninth Planet" KRWG-TV (U-Matic videocassette; UA 98-29) Other astronomy-related manuscript collections in the Archives and Special Collections Department, Archives and Special Collections include:

Philip R. Glaser Photographs (Ms 0433) Walter H. Haas Papers. Ms 0399. Hugh M. Johnson Papers. Ms 0408. Ernst A. Steinhoff Papers. Ms 0260. Latimer J. Wilson Papers. RG2003-078.


Contact Information

  1. Archives and Special Collections Department
  2. New Mexico State University Library
  3. P.O. Box 30006
  4. Las Cruces, New Mexico 88003-8006
  5. Phone: (575) 646-3839
  6. Fax: (575) 646-7477
  7. Email:
  8. URL:


Date Processed: March 2004

Processing Information:

Processed by Melissa Gottwald, 2003-2004, with assistance from Lenny Silverman; initial arrangement and description by Marah deMeule, Christine Moreland-Bruhnke, and Herbert A. Beebe, assisted by Nancy Shockley and Cassandra Begay, 2001-2003.

The processing of the Tombaugh Papers was begun in Spring 2001, under the direction of project archivist Marah deMeule with the aid of processing assistant Christine Moreland-Bruhnke. The processing staff found a lack of coherent original order, and it was decided to process the collection at the item level. At this time a preliminary series organization was established, separating the materials into personal and professional papers, with additional series for photographs and oversize materials. The Personal and Professional Papers series were further broken down into subseries by type of material or, in the Professional Papers, by institution. Another major component of the early processing work was separating the correspondence into the categories of personal and professional correspondence and fan mail. By Summer 2002, both deMeule and Moreland-Bruhnke had left the program. The arrangement work begun under their direction was continued by student assistants.

In March 2003, Melissa Gottwald began work as the new project archivist for the Tombaugh Papers. Under her direction, the preliminary series organization was refined. Major organizational changes included the addition of four series: Printed Matter, Audio-Visual Material, Oral History, and Artifacts. In addition, many of the subseries within the Personal and Professional Papers were further broken down into sub-subseries in order to bring similar materials (such as research files) together. The existing container list was revised in accordance with these changes, and the scope and content note, series descriptions, and biographical sketch were written. The processing project was completed in February 2004.
Register of the Clyde W. Tombaugh Papers, 1908-2000
Edited Full Draft
Processed by Melissa Gottwald, 2003-2004, with assistance from Lenny Silverman; initial arrangement and description by Marah deMeule, Christine Moreland-Bruhnke, and Herbert A. Beebe, assisted by Nancy Shockley and Cassandra Begay, 2001-2003.
© 2004
Language of description
Script of description
Code for undetermined script
Language of description note
Finding aid is in English

Revision Statements

  • June 28, 2004: PUBLIC "-//New Mexico State University::Archives and Special Collections//TEXT (US::NmLcU::0407::Clyde W. Tombaugh Papers)//EN" "nmlcu1#0407.sgml" converted from EAD 1.0 to 2002 by v1to02.xsl (sy2003-10-15).

Repository Details

Part of the New Mexico State University Library Archives and Special Collections Repository

Branson Hall
PO Box 30006
MSC 3475
Las Cruces New Mexico 88003 USA