Pluto
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.
Construction of 13-inch Pluto Dome. Stanley and Guy Sykes in foreground, V. M. Slipher and C. O. Lampland on top of Dome.
Blink Comparator
Early order for the Blink-Comparator from Carl Zeiss
Inquiry regarding the description and manufacturer of the Blink-comparator
New pieces of equipment at Lowell Observatory - the Blink Comparator
The Blink Comparator being kept busy all the time on the examination of star fields taken with the new 13-inch photographic telescope
Zeiss Blink Comparator used at Lowell in the discovery of Pluto in 1930
Group from the Royal Astronomical Society (RAS) visting Lowell Observatory was very disappointed in not meeting Clyde Tombaugh but did see the pair of discovery plates displayed in the Blink Comparator
In 1911 Lampland suggests the purchase of a Zeiss Blink Comparator to aid in the search for Planet X and modifies the apparatus to accommodate larger photographic plates
The Discovery
Lowell Observatory's sole trustee, Roger Putnam, has written Mrs. Lowell about the observation of what may be Planet X and asks if she has any thoughts about its name
Congratulations on the discovery of TransNeptunian Planet
Thanks for the telegram of congratulations on the discovery of TransNeptunian Planet. "We have a new baby at our house".
Congratulations on planet discovery and request for more information thereof for an article in "The Book of Popular Science"
C.A. Robert Lundin's part in the discovery of Pluto
Discovery of new planet has already helped Lundin with a lens order from China.
Observing, measurements of positions and calculations have been consuming every waking moment for the past weeks.
Congratulations on TransNeptunian planet discovery
Diagram of the apparent motion of the planet among the stars.
Photos and Lowell Observatory publications regarding the new planet.
Position of Pluto from photo made at the Observatoire de Juvisy.
Mme. Flammarion's idea of a group of transneptunian planets.
Status of Pluto situation
Status of Pluto situation
All reports indicate "that you have made a real planetary discovery"
Credit for the Discovery
Problem with the treatment of the discovery of Pluto in Professor Baker's new book on Astronomy wherein Tombaugh's name is not mentioned as the discoverer of Pluto, rather Lampland is accredited as the discoverer.
Professor Baker's book and credit for the discovery of Pluto.
Professor Baker's book and credit for the discovery of Pluto.
Professor Baker's book and credit for the discovery of Pluto.
Pluto Orbit Work
The collection of images Carl Lampland made of Pluto from 1930 until his death in 1951 were used by the New Horizon team to help pinpoint Pluto's orbit for the successful Pluto flyby in 2015
G.M. Clemence and Dr. Brouwer are engaged in a research program on motions of the planets and could greatly benefit in using Lampland's valuable series of observations of Pluto as described by Dr. Oort
Valuable series of observations of Pluto by Carl Lampland as described by Dr. Oort.
Evaluation of the observational material on Pluto at Lowell Observatory and elsewhere to determine its exact orbit.
Program for the accurate determination of position of the planet Pluto on the extensive series of photographs made with the 42 inch Lowell reflector is making progress.
Methods of procedure for the measurements and reductions of Pluto plates to establish the revised orbit of the planet based on an article by Dr. Gus Land published in the March, 1949 issue of the Astronomical Journal
Lampland's work on the measurements of positions of Pluto using the 42-inch reflector plates
Lampland's work on the measurements of positions of Pluto using the 42-inch reflector plates.
Suggestion for Carl Lampland to apply to the Office of Naval Research for a small astronomical grant to complete work on orbit of Pluto
Research proposal application on orbits of Pluto and photos of fields of positions of Pluto Feb. 24, & Apr. 5, 1931
Lampland working short-handed with the extended program of planetary atmospheres and the heavy program of position measurements of Pluto.