Lowell Observatory Lowell Observatory Lowell Observatory is an astronomical observatory in Flagstaff, Arizona, United States. Lowell Observatory was established in 1894, placing it among the oldest observatories in the United States, and was designated a National Historic Landmark in 1965. In 2011, the Observatory was named one of "The World's 100 Most Important Places" by TIME. It was at the Lowell Observatory that the dwarf planet Pluto was discovered in 1930 by Clyde Tombaugh. The observatory was founded by astronomer Percival Lowell of Boston's Lowell family and is overseen by a sole trustee, a position historically handed down through the family. The
Goldendale Observatory State Park and north dome a diameter of 10 feet (3 m). The observatory served as the National Astronomical League's official headquarters during a solar eclipse which occurred on February 26, 1979, six years after the observatory opened. Approximately 15,000 people came to the town of Goldendale on that date to observe the eclipse. The Observatory and its lands were acquired by the state of Washington in 1980, after being operated by the Goldendale Observatory Corporation since its dedication on October 13, 1973. The park received its new designation as a "state park heritage site" in 2014. In July 2017, all structures