The Lowell Observatory is legendary in the history of astronomy.
It was at this Flagstaff, Arizona observatory that a high school graduate and amateur astronomer discovered Planet X, later named Pluto, the ninth planet in our solar system.
The former farmer and the first American to discover a planet was named Clyde Tombaugh. He built his own telescopes from discarded farming machinery parts and made astronomical drawings that he sent off to the Lowell Observatory. They were so impressed with Tombaugh’s drawings that they hired him as an observer in the search for Planet X.
Tombaugh used the 13-inch astrograph to take photographs of the night sky. An astrograph is a telescope that has a photographic plate holder where astronomers can take photographs with exposures than can last up to an hour.
The method Tombaugh used To discover the ninth planet was as follows: Tombaugh would aim the astrograph to a section of the night’s sky and make a one hour exposure onto a glass plate. Five or six days later he would make the same exposure in the same location and then he would compare the two developed plates. The stars, which are far beyond our solar system, did not move but Tombaugh found a small spec that moved from left to right. This was a planet orbiting our sun. Tombaugh had discovered Planet X!
Tombaugh later went back to school to earn his masters (Can you imagine his professor asking the class on the first day: “What is your experience with astronomy?” Tombaugh replies, “I discovered Pluto.”) He went on to a long career in astronomy and he died in 1997. He was lucky not to live long enough to see his discovery demoted from a planet to a dwarf planet; Which happened almost ten years after his dead.
Another historic telescope at Lowell Observatory is the 24-inch Clack Refractor. This is the telescope that Percival Lowell used to explore the planet Mars as well as starting the search for Planet X.
It was with this telescope that Lowell made many of his Mauritian observations that raised some eyebrows in the scientific community. Lowell observed “Mauritian Canals” on the surface and he surmised that these were signs of intelligent life. Lowell thought that the canals were used to carry water from the poles to the desert like equator.
While these speculative observations didn’t help Lowell or the Observatory’s reputation, his theories provided fodder for early Science Fiction writers.