Move over Clyde Tombaugh...Milton L. Humason had first crack at Pluto

Milton L. Humason
August 19th, 1891 to June 18th, 1972

According to Wikipedia...

Due to merest chance, Humason missed discovering Pluto. Eleven years before Clyde Tombaugh, Humason took a set of four photographs in which the image of Pluto appeared.* There is persistent speculation that he missed discovering the planet because it fell on a defect in the photographic plate. This is unlikely given that it appeared in four separate photographs over three different nights.

*Nicholson, Seth B.; Mayall, Nicholas U. (January 1931). "Positions, Orbit, and Mass of Pluto". Astrophysical Journal 73.

Now, Humason was a very interesting person who had no formal education--not even a high school diploma let alone a Ph.D. but yet he worked through the ranks from a floor sweeper to a meticulous Mt. Wilson staff member appointed by George Ellery Hale.

And, it has even been mentioned that "The myth that the expansion of the Universe was discovered by Hubble was first propagated by Humason (1931). The true nature of this discovery turns out to have been both more complex and more interesting."

Read...

"DISCOVERY OF THE EXPANSION OF THE UNIVERSE" by Sidney van den Bergh