Clyde Tombaugh discovered Pluto in 1930, at the Lowell Observatory where he worked as a junior astronomer. Tombaugh was a keen amateur astronomer who, having reached the limits of the telescope his father bought him as a child, built his own. He took his astronomy very seriously. Professional astronomers at Lowell Observatory were so impressed by the detailed sketches he sent them of Jupiter and Mars that they offered him a job as a junior astronomer. His job was to assist in the search for the mystery Planet X, by carefully studying multiple photographs of the same piece of sky, day in and day out, looking for anything that changed. After ten month of soul-crushing work, he discovered the planet, which was named Pluto. Which just goes to show what can be achieved by dedicated amateur astronomers!
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