American astronomer (1906–1997) best known for discovering Pluto in 1930. Two items: ALS, three pages on two sheets, 8.5 x 11, New Mexico State University letterhead, February 1, 1989, discussing his research related to the possibility of planets beyond Pluto. In part: “There may be planets (probably small ones) beyond the orbit of Pluto, which are too faint to have been recorded on my 14 x 17 inch planet search plates, during an exhaustive and extensive search I made at the Lowell Observatory, Flagstaff, Arizona, 1929–1943…. The various regions of the sky must be photographed at the proper time of the year when they are opposite the sun…. There are many other astronomical projects that are more important and have a much greater priority. The sky is too big, and too many stars!” Tombaugh also goes into great detail on his own research, technical requirements, and the substantial expense involved in such observations. Also included are three photocopied pages from Tombaugh’s book The Planet Pluto, each bearing his handwritten notations and one signed “Clyde W. Tombaugh.” Accompanied by the original mailing envelope addressed in Tombaugh’s hand. In fine condition. R&R COA.
