Historic Research

Lowell Observatory boasts a long history of astronomical research and discovery, including VM Slipher’s revolutionary recessional velocity measurements and Clyde Tombaugh’s discovery of Pluto.

Historic Highlights

This timeline reflects some of the more significant milestones related to Lowell Observatory’s research legacy.

1896 Clark Refractor Built

Percival Lowell hired the eminent telescope makers, Alvan Clark & Sons, to build a spectacular 24-inch refractor.

1912 Expanding Universe

Astronomer V.M. Slipher first detected the expanding universe after painstakingly imaging spectra from what we know today as galaxies.

1930 Pluto Discovered

Clyde Tombaugh, who taught himself astronomy while growing up on a farm, discovered Pluto using the 13-inch Lawrence Lowell Telescope.

1957 Proper Motion Survey

Henry Giclas commenced a proper motion survey, using Clyde Tombaugh’s Pluto search plates as the first epoch. This program would last for 23 years and cover the entire northern hemisphere and ¼ of the southern hemisphere.

1958 Lighting Ordinance

At the urging of Lowell Observatory scientists, Flagstaff enacted the world’s first lighting ordinance to protect dark skies.

1961 Lunar Mapping

Starting in 1961, cartographers worked with scientists to create maps of the Moon in support of the Apollo Moon Program.

1977 Rings of Uranus

A team of astronomers, including several from Lowell, used airborne and ground-based telescopes to discover a ring system around Uranus.

1988 Pluto’s Atmosphere

Astronomers from Lowell and elsewhere used airborne and ground-based telescopes to discover Pluto’s atmosphere.

2001 International Dark Sky City

The International Dark Sky Association named Flagstaff as the world’s first International Dark Sky Community, in recognition of the community’s long tradition of protecting dark skies.

2012 Lowell Discovery Telescope

The 4.3-meter Lowell Discovery Telescope saw first light on April 3, 2012.

2015 Pluto Flyby

After a journey of more than 9 years, the New Horizons probe flew by Pluto on July 14, 2015, with Lowell astronomer Will Grundy leading the mission’s surface composition team.