1906

1922

1925

1926

1927-28

1929

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

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 University of Kansas, Lawrence, Kansas

1932

Entered University of Kansas as a freshman; continued planet search work at Lowell Observatory in the summers while pursuing his university education

1934

1936

1939

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"

1943-45

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

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, one nova, and showed the full extent of the Great Perseus-Andromeda Stratum of Extra-Galactic Nebulae

1945-46

Visiting Assistant Professor in Astronomy at University of California at Los Angeles

1946

Moved to Las Cruces, New Mexico

1946-50

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

1950-55

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 proper motion stars

1953-55

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

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 among the founding members of the Las Cruces Unitarian Fellowship (now Unitarian Universalist Church of Las Cruces)

1956-58

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

1958-73

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

1959-68

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

1960

Received honorary doctorate from Northern Arizona University, Flagstaff, Arizona

1961-70

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

1970

1972

Work to establish Astronomy graduate program in at NMSU moves forward with the submission of a "Request for Preliminary Accreditation for a Degree of Doctor of Philosophy in Astronomy"

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

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 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 postdoctoral fellowship at New Mexico State University established

1987-88

Conducted national speaking tour to raise funds for Tombaugh Scholars Fund

1997

Jan. 17: Died at his home near Las Cruces, New Mexico