Lowell Observatory

Lowell Observatory is a private, non-profit astronomical research institution located in Flagstaff, Arizona. It was founded in 1894 by the astronomer Percival Lowell and is one of the oldest observatories in the United States. The institution is renowned for its historic discoveries, including the detection of Pluto and evidence for the expansion of the universe. It continues to be a major center for astronomical research and public education.

History

The observatory was established by Percival Lowell, a mathematician and astronomer fascinated by the possibility of life on Mars, to study the Solar System. He chose the site near Flagstaff, Arizona for its high elevation and clear skies. Early work focused on observations of Mars, leading to Lowell's controversial maps of Martian "canals." Following his death in 1916, the institution continued under the direction of trustees, shifting focus to broader astronomical research. A pivotal moment came in 1930 when astronomer Clyde Tombaugh, working here, discovered the dwarf planet Pluto, a search initiated by Lowell himself. Throughout the 20th century, it contributed to foundational cosmology, with work by Vesto Slipher providing early evidence for the expanding universe, data later used by Edwin Hubble.

Facilities and telescopes

The main campus, Mars Hill, overlooks Flagstaff, Arizona and houses several historic instruments. The original Clark Refractor, a 24-inch Alvan Clark & Sons telescope installed in 1896, remains in use for public programs. The Pluto Discovery Telescope, a 13-inch astrograph, was the instrument used by Clyde Tombaugh for his famous discovery. For modern research, the observatory operates the 4.3-meter Lowell Discovery Telescope (LDT) located at a dark-sky site near Happy Jack, Arizona; it is one of the largest telescopes in the continental United States. Other active research sites include the Anderson Mesa station, home to the NASA-funded Lowell Observatory Near-Earth-Object Search (LONEOS) telescope, and the John S. Hall Telescope.

Research and discoveries

Research programs span planetary science, stellar physics, and galactic astronomy. Historically, Vesto Slipher's measurements of redshift in nebulae here were the first observational evidence for what became known as Hubble's law. The long-term study of planetary atmospheres includes detailed monitoring of Jupiter and Saturn. Current projects utilize the Lowell Discovery Telescope for exoplanet characterization, studies of near-Earth objects, and the composition of Kuiper belt objects. Scientists are also involved in major collaborations like the NASA Lucy mission to the Trojan asteroids and the Hubble Space Telescope and James Webb Space Telescope observation programs.

Public outreach and education

It is a leading center for astronomy education, welcoming tens of thousands of visitors annually to its flagship campus in Flagstaff, Arizona. The Giovale Open Deck Observatory provides public access to a suite of modern telescopes for night sky viewing. The interactive Putnam Collection Center and the historic Rotunda Museum showcase scientific artifacts and exhibits. The institution also hosts nightly viewing sessions, seasonal programs like the "Star Party," and lectures by research astronomers. Educational partnerships extend to local schools, Northern Arizona University, and programs for amateur astronomers through the Astronomical League.

Notable astronomers

Many distinguished scientists have worked here. Founder Percival Lowell pioneered its early planetary studies. Vesto Slipher, the longtime director, made groundbreaking measurements of galactic redshifts. Clyde Tombaugh achieved worldwide fame for his discovery of Pluto. Carl Otto Lampland contributed significantly to planetary photography and instrument design. John S. Hall pioneered the use of spectropolarimetry to study interstellar magnetic fields. More recent notable figures include Henry Giclas, known for proper motion surveys, and Larry Wasserman, an expert on occultation astronomy.

Category:Astronomical observatories in Arizona Category:Buildings and structures in Coconino County, Arizona Category:Organizations based in Arizona