Browse Items (1220 total)

Discovery images of Pluto's moon, Charon, captured by astronomer Anthony Hewitt. The images were then sent to astronomer Jim Christy for further analysis, and it was Christy who made the discovery of Pluto's moon.

A telegram from Clyde Tombaugh's parents congratulating their son on his discovery of Planet X.

Logbook covering the work on the 42-inch Spectro Radiometer and Auxiliary Equipment from March 1944 - November 1946

Logbook covering the Construction of Radiometric Equipment at Lowell Observatory (1940-1944)

The Lowell Observer, Spring 1999, Issue 42

The Lowell Observer, Spring 1997, Issue 34

The Lowell Observer, Summer 2008, Issue 79

Logbook of the Radiometric Observations at Lowell Observatory from November 1941 - December 1943. Objects include:
Venus
Mars
Mercury
Moon

Plates taken in 1915 by Thomas Gill at Lowell Observatory. Unbeknownst to Gill, these plates contained images of Pluto. The team that discovered Pluto in 1930 later realized this after comparing their own plates to pre-existing ones .

Photograph of Clyde Tombaugh at the entryway of the 13 inch telescope. Tombaugh captured images using this telescope on January 23rd and 29th in 1930 that contained Planet X.