Pluto Discovery Telescope
The Pluto Discovery Telescope is a 13-inch astrograph built in 1929. C. A. Robert Lundin crafted the 33-cm Cooke triplet astrographic objective lens, which was chosen for its ability to eliminate and correct distortion. The astrograph ended up being over budget but proved to be worth it when Clyde Tombaugh discovered Pluto on February 18, 1930. Tombaugh took images with the 13-inch astrograph on the nights of January 23rd and 29th, 1930 and compared them using the Zeiss Blink Comparator. A speck of light that "jumped" back and forth between the two plates signaled the discovery of the long sought after Planet X, later named Pluto. Lowell Observatory staff announced the discovery on March 13, Percival Lowell's birthday.
Lowell Observatory restored the Pluto Telescope and dome in 2018, and today it is a featured stop on public tours. Its official name is the A. Lawrence Lowell Telescope (after Percival Lowell's brother, who donated the funds for its construction).