In this 1931 file photo, Clyde Tombaugh poses with the telescope through which he discovered th …

Clyde Tombaugh poses with the telescope through which he discovered the Pluto at the Lowell Obs ...

Clyde Tombaugh poses with the telescope through which he discovered the Pluto at the Lowell Observatory on Observatory Hill in Flagstaff, Ariz., in 1931. (AP Photo)