Historical Timeline
Signature events from our past.
Lowell Observatory has been in operation for more than 125 years. Our history is punctuated by many important discoveries and other milestones.
Here are some of the biggest, including important scientific discoveries, recognition events, construction milestones, and other organizational milestones.
1894 - 1965
1894 Observatory Founded
Percival Lowell opened his observatory in Flagstaff, Arizona, initially to search for life on Mars.
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 of what we know today as galaxies.
1916 Percival Lowell Dies
Observatory founder Percival Lowell died at the age of 61. He is entombed in a mausoleum near his beloved 24-inch Clark Refractor.
1916 Rotunda Built
The Rotunda forms the central portion of the Slipher Building and originally housed the observatory’s library. It now serves as a museum.
Learn More1928-’29 13-inch Telescope Built
Officially named the Lawrence Lowell Telescope, most people know this as the “Pluto Discovery Telescope”.
1930 Pluto Discovered
Clyde Tombaugh, who taught himself astronomy while growing up on a farm, discovered Pluto using the 13-inch Lawrence Lowell Telescope.
History of Pluto1958 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.
Our Lunar Legacy1965 Historic Landmark
The National Park Service declared Lowell Observatory a National Historic Landmark in recognition of its scientific and cultural heritage.
1977 - 2019
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.
1994 Steele Visitor Center
In celebration of its centennial, Lowell opened the Steele Visitor Center in 1994.
1999 Save America’s Treasures
First Lady of the United States Hillary Clinton visited Lowell and identified
it for inclusion in her Save America’s Treasures program.
2012 Lowell Discovery Telescope
The 4.3-meter Lowell Discovery Telescope saw first light on April 3, 2012.
Discover the LDT
2014 Putnam Collection Center
In 2014, Lowell opened the Putnam Collection Center to house its library and collection of artifacts and documents.
2019 GODO Opens
Lowell opened the Giovale Open Deck Observatory on October 5, 2019. The public facility features a roll-off building housing six telescopes.
Discover the GODO