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Observatory · Flagstaff, Arizona
Lowell Observatory
An astronomical observatory founded in 1894 on a hill in Flagstaff, where Pluto was discovered in 1930. It has exhibits, guided tours and nighttime telescope sessions.
Illustrative images. The pictures in this guide are illustrations based on the real place, not photographs, and may differ from it.
Discover
About Lowell Observatory
Lowell Observatory was founded in 1894 by astronomer Percival Lowell atop Mars Hill, a hill west of downtown Flagstaff. Lowell chose the site for its elevation and clear skies and spent years observing Mars, convinced there were canals on the planet. In 1930, a young assistant, Clyde Tombaugh, discovered Pluto there by comparing photographic plates of the sky.
The visit includes the 1896 Clark refractor in a wooden dome, Lowell’s mausoleum and exhibits on the solar system and the observatory’s history. Guides explain the research the institution still conducts, now with larger telescopes located outside the city.
At night, when the sky is clear, there are observing sessions with telescopes of various sizes, viewing planets, double stars and nebulas depending on the season. Flagstaff was the first city recognized as an International Dark Sky City, in 2001, for its lighting regulations that protect astronomical observation.
A more recent public astronomy park, with a telescope platform and a planetarium, has expanded the space available to visitors.
Before you go
Practical information
Cidade Turismo reviews its information regularly, but something may have changed. Check with the place before planning your trip.
How much time to set aside
Two to three hours; longer in the evening for observing.
Best time
Late afternoon, combining the daytime visit with the night session. Moonless, cloudless nights are best for the telescopes.
How to get there
It’s on Mars Hill, about 2 km from downtown Flagstaff, with on-site parking. You can reach it by car or rideshare.
Tip
Buy tickets in advance on busy nights and bring warm clothing: even in summer, nights are cold at 2,200 meters.
Official website
Get your questions answered
Frequently asked questions about Lowell Observatory
Was Pluto discovered at Lowell Observatory?
Yes. Clyde Tombaugh found Pluto in 1930 by comparing photographic plates taken at the observatory. The story is told in the exhibits and guided tours.
Can you look through the Lowell Observatory telescopes?
Yes, during nighttime sessions when the sky is clear. The schedule changes with the season; check before you go.
How much time should I allow for the Lowell Observatory?
Two to three hours for the exhibits and guided tour; those staying for nighttime observing should add one or two more hours.