DISCOVERED PLUTO

Clyde Tombaugh was just 24 when he made the find

Clyde William Tombaugh was born on a farm in Streator, Illinois, on 4 February 1906. Tombaugh had an interest in astronomy as a child, which was encouraged by his father and his uncle, who had his own telescope.

When the family moved to a new farm in 1922, disaster struck. A powerful hail storm destroyed much of their crops, and Tombaugh’s plans to study astronomy at university had to be scrapped. Undeterred, he started to teach himself geometry, and in 1925 he set about building a large telescope of his own. The materials were expensive, so he took a second job in order to buy them. Unsatisfied with his first instrument, he laboured on for two years, polishing mirrors and grinding lenses, and in 1928 he produced a 230mm (9-inch) reflector he was satisfied with. Tombaugh had become a skilled telescope maker and would construct 30 more during his lifetime.

Tombaugh set to work with his creation under the dark Kansas skies and made many detailed drawings of Mars and Jupiter. He sent his drawings to Vesto Slipher, director of the Lowell Observatory, who was so impressed by Tombaugh’s observational skills and draughtsmanship that he offered him a job. Tombaugh started at the observatory in 1929.

During the 14 years Tombaugh spent at the Lowell Observatory he was finally able to complete his education, obtaining his bachelors and masters degrees from the University of Kansas. Tombaugh made other discoveries during his time at Lowell, which included hundreds of new variable stars and asteroids, and two new comets. But his main achievement was the discovery of Pluto in February 1930.

After World War II he moved to New Mexico State University in Las Cruces, where he remained until he retired in 1973. Even into retirement he kept an active interest in astronomy and continued observing the night sky with his homemade telescopes into his early 80s. He died in 1997 and a small amount of his ashes were placed on the New Horizons spacecraft.