This collection celebrates the Year of Pluto. Clyde Tombaugh discovered Pluto at Lowell Observatory in 1930, and 2015 marks the flyby of NASA's New Horizons spacecraft. The collection contains letters, calculations, photographs and documents that illustrate the history of the search for Pluto, its discovery, and the subsequent public excitement and fascination.
![City of Flagstaff Proclamation declaring March 13, 1980 "Lowell Observatory - Clyde Tombaugh Day"](/img/placeholder.gif?1735518749 "City of Flagstaff Proclamation declaring March 13, 1980 "Lowell Observatory - Clyde Tombaugh Day"")
