Named by the Lowell Observatory for Clyde W. Tombaugh {1906–1997}, the discoverer of Pluto, on the occasion of a symposium on Pluto, held on the fiftieth anniversary of its discovery, 1980 Feb. 18. Tombaugh marked, during the course of his blink examination, over 4000 minor planets on plates obtained with the 0.33-m photographic telescope during the trans-Saturnian search program at the Lowell Observatory. (M 5280) _ _.