On February 18, 1930, a young astronomer named Clyde Tombaugh made history. Just a year before, Tombaugh had been given the job of finding “Planet X” – the then-theoretical ninth planet beyond Neptune.
The task was not simple. He had to take pairs of photographs of the night sky spaced two weeks apart and manually examine – there were no computers for this job back in the 1930s! – the pairs to see if any of the objects in the photographs had changed position. That night, Tombaugh finally hit the jackpot: a moving object appeared in the photos. He had discovered the now-demoted planet Pluto, thanks to the telescopes of the Lowell Observatory.
The Lowell Observatory was founded by the astronomer Percival Lowell in 1894. Located in Flagstaff, Arizona, it is one of the oldest observatories in the United States and is considered as a National Historic Landmark. Besides the discovery of Pluto in 1930, Lowell Observatory had many other notable contributions to the field of astronomy. This was where the three largest known stars were discovered, where the atmosphere of Pluto was determined, and – just recently – where evidence of water vapor in the atmosphere of an extra solar planet was found.
Visitors to the observatory may tour the facilities and see the several different telescopes during the day. At night, visitors are allowed to look through the telescopes to see the wonders of the night sky. The original 24-inch Clark Refracting Telescope is the main telescope used for public education, while the 13-inch telescope Clyde Tombaugh used to find Pluto is also in display.
Another telescope of note in the observatory is the Discovery Channel Telescope. Currently being built with the help of Discovery Communications, the telescope is expected to become the fifth largest in the United States and is slated to further enhance the research and education abilities of the observatory.