Lowell Observatory: Where Pluto Was Discovered in Arizona’s Skies
Beginnings Above Flagstaff
Situated on Mars Hill overlooking the city of Flagstaff, Lowell Observatory stands as one of the oldest and most historically significant astronomical observatories in the United States. Established in 1894 by astronomer Percival Lowell, the facility became internationally renowned for planetary studies and would eventually play a key role in the discovery of Pluto.
Lowell selected the site for its high elevation, dry climate, and minimal light pollution—all optimal conditions for stargazing. From its earliest days, the observatory sought to expand human understanding of the solar system, a mission that continues to shape its identity more than a century later.
Scientific Impact and Discoveries
The observatory's greatest claim to fame came in 1930, when astronomer Clyde Tombaugh, working under Lowell’s vision, discovered Pluto using photographic plates captured with the observatory’s 13-inch astrograph. This landmark event made Lowell Observatory a household name and contributed to Flagstaff’s growing importance in space science.
Over the years, Lowell researchers have contributed to:
Mapping of Martian canals and theorizing about potential life on Mars (a controversial pursuit at the time)
Observations that supported the expanding universe theory
Continued work in exoplanet detection, stellar formation, and galactic structures
Today, the observatory operates the Lowell Discovery Telescope, one of the most advanced astronomical tools in the continental U.S.
Educational Mission and Public Access
Unlike many research-only institutions, Lowell Observatory has always embraced public engagement. Visitors to the observatory can:
Peer through historic and modern telescopes during guided sessions
Attend interactive exhibits and lectures on current astronomical research
Explore museum-quality displays about the solar system, space exploration, and the history of Pluto
Thousands of people each year visit the site, making it one of Arizona’s premier science tourism destinations. Its programs emphasize not just scientific literacy, but also curiosity and wonder.
Legacy and Preservation
Lowell Observatory was designated a National Historic Landmark in 1965 due to its ongoing contributions to American astronomy. Its original telescope domes, preserved and still functional, represent a physical connection to the era of early planetary discovery.
The observatory has also been a key driver behind Flagstaff’s designation as the world’s first International Dark Sky City, working with local government to limit light pollution and maintain conditions for research and public viewing.
A Heritage of Cosmic Curiosity
Lowell Observatory continues to be a bridge between Arizona’s landscape and the boundless sky above. It is a place where science, history, and inspiration converge—honoring its founding vision while embracing the most modern methods of exploration.
From the discovery of Pluto to the latest research on distant stars, Lowell remains a testament to Arizona’s enduring role in unlocking the mysteries of the universe.