Там же (в вики) вроде написано, что на чёрно-белом фото телескоп, который он сделал сам и частично благодаря которому получил работу
https://starchild.gsfc.nasa.gov/docs/St ... baugh.htmlЦитата:
In 1928 Clyde completed the construction of a very accurate 23-centimeter reflector. The mount for this telescope was built from part of the crankshaft from a 1910 Buick and discarded parts from a cream separator! Nevertheless, it was with this telescope that Clyde made the observations responsible for a job offer from the Lowell Observatory. Clyde made very detailed drawings of his telescopic observations of Jupiter and Mars. He sent the drawings to astronomers at the Lowell Observatory asking for their comments and suggestions. What he received instead was an offer to come to Lowell to work as a junior astronomer. Clyde accepted the job and joined the search for Percival Lowell's "Planet X", a planet beyond Neptune.
А Плутон был открыт на этом:
https://lowell.edu/pluto-telescope-renovation/Цитата:
Like that instrument, the lens of the Pluto Telescope, measuring 13-inches in diameter, was crafted by the Alvan Clark and Sons telescope making firm of Cambridge, Massachusetts.
Это рефрактор (точнее, астрограф):
https://en.wikipedia.org/wiki/AstrographЦитата:
One well-known case of an astrograph used in a discovery is Clyde Tombaugh’s discovery of the dwarf planet Pluto in 1930. Tombaugh was given the job of hunting for a suspected "9th planet" to be achieved by systematically photographing the area of the sky around the ecliptic. Tombaugh used Lowell Observatory's 13-inch (330 mm) (3 lens element), f/5.3 refractor astrograph, which recorded images on 14-by-17-inch (360 mm × 430 mm) glass plates.
29.06.2018, 12:21 
В реальности он был открыт на 13-дюймовом (т.е. 33 см) астрографе, и не глазом, а по фотопластинкам.
