Clyde Tombaugh with the Blink Comparator

Clyde Tombaugh with the Blink Comparator

Pluto; Planet X; Astronomy; Planetary discovery; Tombaugh, Clyde W.; Blink Comparator; Lowell Observatory; Flagstaff.

Discoverer of Pluto, Clyde Tombaugh, demonstrates how to use the blink comparator which he used to make the planetary discovery. In February of 1930, Tombaugh was comparing two slides of the night sky when he noticed movement in the region where Percival Lowell predicted Planet X would be. Using the blink comparator, Tombaugh was able to see the shift of a singular dot from one image to the next, which indicated a celestial body that might be the elusive Planet X. Tombaugh and the other astronomers at Lowell Observatory compared images using the blink comparator for several weeks before making the final announcement that they had discovered a new planet. Lowell Observatory lent the blink comparator to the Smithsonian Air and Space museum in 2015 for use in their Exploring the Planets gallery, but the equipment has since been returned to Flagstaff as part of Lowell's Pluto exhibit.

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Black and white photograph

Image

Pluto Collection. a_0174a.tif