Percival Lowell1906
Percival Lowell begins an extensive search for a possible ninth planet, which he calls Planet X.
United States of America · Science / Astronomy. Chronological records rendered directly from the World History Database.
Percival Lowell begins an extensive search for a possible ninth planet, which he calls Planet X.
Lowell and William H. Pickering suggest several possible celestial coordinates for the predicted Planet X.
Lowell Observatory captures faint images of Pluto, but the object is not recognised as the predicted planet.
Lowell continues the search for Planet X until his death in 1916 without identifying Pluto.
Lowell Observatory director Vesto Melvin Slipher assigns Clyde Tombaugh the task of searching for Planet X.
Tombaugh is assigned to systematically photograph the night sky and compare paired plates with a blink comparator in the renewed search for Planet X.
Tombaugh exposes one of the photographic plates later used, with the January 29 plate, to identify Pluto's motion.
Tombaugh exposes the second of the two photographic plates later used to identify Pluto's motion against background stars.
Tombaugh identifies Pluto as a moving object while comparing photographic plates taken on January 23 and January 29.
Using a blink comparator, Tombaugh identifies a moving object on plates taken January 23 and January 29, discovering Pluto.
News of Pluto's discovery is telegraphed from Lowell Observatory to the Harvard College Observatory.
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