In 1905, Carl Lampland began the photographic search for the planet that Percival Lowell was convinced revolved beyond the orbit of Neptune (Planet X). This search culminated in Clyde Tombaugh's discovery of Pluto in 1930. Lampland was involved in the work throughout, taking many of the earlier photos himself and scanning them on the Blink Comparator.
This exhibit is a small sample of Lampland's correspondence. All of his letters pertaining to Pluto are available as PDF files on our Collections page.