The planet Pluto was discovered by astronomer Clyde Tombaugh on this date in 1930. He used a 13-inch astrograph to photograph and identify the planet. Tombaugh also believed in the possiblily of extraterrestrial activity and claimed to have seen UFOs.
Johannes Hevelius, Machinae Coelestis Pars Prior [and Posterior]
[Celestial machines, or astronomical instruments], 1673-79.
In 2006 Pluto was designated a dwarf planet, minor planet 134340. Tombaugh may not have been too upset at this "downgrade", as Pluto was only one of many of his astronomical discoveries:
Tombaugh discovered nearly 800 asteroids during his search for Pluto and years of follow-up searches looking for another candidate for the postulated Planet X. Tombaugh is also credited with the discovery of comet C/1931 AN, though its orbit is currently unknown. He also discovered hundreds of variable stars, as well as star clusters, galaxy clusters, and a galaxy supercluster.—Wikipedia
Out of the darkness, the planet Pluto. Clyde W. Tombaugh, Patrick Moore.
Clyde Tombaugh: discoverer of planet Pluto. David H. Levy.