Star Treks at Lowell Observatory in Flagstaff

This observatory helped create maps of the moon and is home to the telescope that helped an observatory assistant discover Pluto.

In 1930, 24-year-old observatory assistant Clyde Tombaugh took pictures through a telescope at Lowell Observatory in Flagstaff, Ariz., and spotted something very unusual. It turned out to be Pluto. Thirty-one years later, the observatory became part of another momentous event. In the race to be the first country to put people on the moon, President John F. Kennedy announced in 1961 that astronauts from the United States would land on the moon’s surface before the end of the decade.

There was only one large problem. No detailed map of the moon existed.

Yet,  Lowell Observatory became ground zero for mapping the moon, thanks to the famed Clark Telescope, which was built in 1896. Working around-the-clock for a decade, groups of airbrush artists and scientists used the telescope to look at the topography of the moon and draw beautifully detailed maps of the moon’s surface.

These maps proved critical to assisting in the astronauts in deciding where to land on the moon, says Kevin Schindler, Lowell Observatory’s historian.

Clark Telescope at Lowell Observatory in Flagstaff
Clark TelescopePhoto courtesy of Lowell Observatory

Visit Lowell Observatory Today

Giovale Open Deck Observatory at the Lowell Observatory in Flagstaff
Giovale Open Deck Observatory at the Lowell Observatory in Flagstaff (Photo: Courtesy Lowell Observatory)

Today, you can tour the beautiful grounds of the observatory with friendly, knowledgeable guides and experience the universe though widescreen multimedia shows, exhibits and live presentations. Learn more at

Be sure to check out the interactive Space Guard Academy exhibit, which also is popular. The observatory’s Junior Astronomer is a great program that allows kids to fill out a packet on-site and receive a patch.

The Giovale Open Deck Observatory opened opened in 2019, which is a public observing plaza featuring six advanced telescopes for viewers to see star clusters, galaxies and more.

You also can view the moon’s craters and sometimes see Saturn’s rings through the 32-foot-long Clark Telescope. The telescopes are housed in a variety of interesting buildings that pop up like giant mushrooms from the ponderosa forest floor.

“Of all the traditional nine planets, only Pluto was discovered in this country, so it’s a neat piece not only of scientific history but American history,” says Schindler.

Clark Telescope Dome at Lowell Observatory in Flagstaff
Clark Telescope Dome at Lowell Observatory in Flagstaff Photo: Courtesy Lowell Observatory

How Pluto Was Discovered

But the story behind Tombaugh is pretty interesting, too. When he arrived at Lowell, it was 1930, and he had come to Lowell from Burdett, Kan., where a hailstorm devastated his family’s harvest and destroyed his hopes of studying at university. On his family farm, he built his own telescopes to explore the night skies. After he sent his sketches of Jupiter and Mars to the Lowell Observatory, the self-trained astronomer was hired.

Once hired, he worked with a new telescope at Lowell Observatory in Flagstaff, Ariz. It had been built specifically to aid in the search for the elusive Planet X, a theoretical ninth planet. But he spent a lot of time looking at sets of glass negatives.

“There were two steps [in identifying new planets]: taking photos and analyzing them,” says Kevin Schindler. “Clyde searched the photos that were basically filled with tiny dots and looked for something that changed position.”

What he found was Pluto.

For more information:
(928) 774-3358
1400 West Mars Hill Road, Flagstaff, Arizona, 86001