I was away on last Friday so I didn't get to post this but on Feb 18th, it
was the 75th
anniversary of Pluto's discovery.
The planet Pluto turns 75 this month. Clyde Tombaugh discovered the ninth
planet in the solar system on the afternoon of February 18, 1930 while he meticulously
examined a pair of deep sky photographs at Lowell Observatory. Tombaugh exposed
the photographs on two nights in late January using the Observatory's 13-inch
Abbott Lawrence Lowell Telescope. Then, as part of the carefully planned and
executed planet search, Tombaugh "blinked" the two exposures using
a machine called a comparator, looking for motion of objects captured on film.