AHO members engage in various joint activities aligned with alliance objectives: astronomical site, asset, and data preservation; collaborative public engagement and media projects; STEM-focused outreach; and strategic collaboration on mature facility operations.
There are two types of membership: “Voting” and “Associate” (see Bylaws Article 3).
To nominate an institution or individual for membership, please use our contact form.
Detroit Observatory
est. 1854
Ann Arbor, MI, USA
University of Michigan
Third largest refracting telescope in the world (1857)
Fitz Refracting Telescope (0.32m, 1857)
Meridian Circle Telescope (1854)
Austin Edmister (assistant director)
Dominion Astrophysical Observatory
est. 1918
Victoria, BC, Canada
National Research Council Canada
Second largest telescope in the world (1918)
Plaskett Telescope (1.8m reflector, 1918)
48-inch telescope (1.2m reflector, 1961)
Dennis Crabtree (vol-professional)
Website
History
Research
Visiting
Observing
Programs
Events
Tour
Griffith Observatory
est. 1935
Los Angeles, CA, USA
City of Los Angeles
The most viewed telescope in the world (> 8.4 million visitors)
12-inch/9½-inch telescopes (0.3m/0.25m refractors, 1935/55)
Coelostat and Solar Telescopes (1935)
Ed Krupp (director)
Lick Observatory
est. 1888
Mt. Hamilton, CA, USA
University of California Observatories
Largest refractor in the world (1888)
The world's first permanently occupied mountain-top observatory
36-inch James Lick ("Great Lick") Refractor (0.9m, 1888)
36-inch Crossley Reflector (0.9m, 1879/1896)
20-inch Carnegie Double Astrograph (0.5m refractors, 1941)
22-inch Tauchmann Reflector (0.5m, 1954)
120-inch Shane Telescope (3m reflector, 1959)
Coudé Auxiliary Telescope (0.6m reflector, 1969)
Matthew Shetrone (deputy director)
Website
History
Research
Visiting
Observing
Programs
Tour
Live Cams
Archives
Events
Lowell Observatory
est. 1894
Flagstaff, AZ, USA
Mormon Lake, AZ, USA
Discovery of Pluto (1930)
24-inch Clark Telescope (0.6m refractor, 1896)
13-inch A. L. Lowell Astrograph (0.3m refractor, 1929)
W. Lowell Putnam (trustee)
Website
History
Research
Visiting
Stargazing
Programs
Exhibits
Archives
Events
News
McCormick Observatory
est. 1885
Charlottesville, VA, USA
University of Virginia
Second largest refractor in the world (with USNO, 1885)
26-inch refracting telescope (0.65m, 1885)
Steve Majewski (chair)
McDonald Observatory
est. 1939
Fort Davis, TX, USA
University of Texas
Second largest telescope in the world (1939)
Third largest telescope in the world (1968)
Otto Struve Telescope (2.1m reflector, 1939)
Harlan J. Smith Telescope (2.7m reflector, 1968)
0.8m telescope (reflector, 1970)
0.9m telescope (reflector, 1956)
Katie Kizziar (asst. director for education & outreach)
Website Research Visiting Observing Programs Media Live Streams News
Mount Wilson Observatory
est. 1904
Mt. Wilson, CA, USA
Mount Wilson Institute
Largest telescopes in the world (1908 and 1917)
Discovery of the cosmic expansion
100-inch Hooker Telescope (2.5m reflector, 1917)
60-inch telescope (1.5m reflector, 1908)
60-ft (18m) Snow Solar Telescope (1905)
150-ft (46m) solar tower (1912)
Timothy Thompson (science director)
Website History Visiting Observing Programs Events Live Cams Tour
Palomar Observatory
est. 1948
Palomar Mountain, CA, USA
Caltech
Largest telescope in the world (1949)
Largest Schmidt in the world (1948)
Palomar sky surveys (1958 and 2000)
Discovery of quasars (1963)
Discovery of Eris (2005) and other TNOs
200-inch Hale Telescope (5m reflector, 1949)
48-inch Samuel Oschin Telescope (1.2m Schmidt, 1948)
18-inch telescope (0.46m Schmidt, 1936)
60-inch telescope (1.5m reflector, 1970)
Andy Boden (deputy director)
Website History Research Visiting Tour Exhibits Live Cams Archives News
Pic du Midi Observatory
est. 1878
Pic du Midi de Bigorre, France
Paul Sabatier University (Toulouse III)
World's first high-mountain observatory
Formally discredited Martian canal theory
Mapped the surface of the Moon for the Apollo missions
Detailed Venus and Mars atmospheric studies
Discovery of Saturn's moon Helene
Invention of the coronagraph
Lyot coronagraph (1935)
Jean Rösch telescope (0.5m refractor, 1961)
T60 telescope (0.6m reflector, 1910/1945)
T1 telescope (1m reflector, 1963)
Rémi Cabanac (science director)
Website 1 Website 2 History Research Visiting Stargazing Programs Exhibits Live Cams News Events
Sommers-Bausch Observatory
est. 1953
Boulder, CO, USA
University of Colorado
Historic headquarters of the High Altitude Observatory
Complementary to coronagraph at the Climax Observatory
Pioneer in ground-based CCD astronomy
24-inch Boller & Chivens telescope (0.6m reflector, 1973)
Gleason heliostat (1973)
10.5-inch Bausch telescope (0.26m refractor, 1953)
Rose Smith (observatory manager)
Van Vleck Observatory
est. 1914
Middletown, CT, USA
Wesleyan University
20-inch Alvan Clark Great Refractor (0.5m, 1922)
24-inch Perkin Telescope (0.6m reflector, 1966)
Roy Kilgard (associate professor)
Vatican Observatory
est. 1577
Albano Laziale RM, Italy
Tucson, AZ, USA
Mt. Graham, AZ, USA
Vatican City State
One of the oldest observatories in the world
Establishment of the Gregorian calendar
Participation in the Carte du Ciel survey
Carte du Ciel Telescope (0.33m double refractor, 1891/1942)
Schmidt telescope (0.65m, 1942)
Zeiss visual refractor telescope (0.4m, 1935)
Zeiss double astrograph (0.6m reflector/0.4m refractor, 1935)
Paul Gabor (vice director)
Website 1 Website 2 History Research Programs Visiting Tour 1 Tour 2 Media Events News Podcasts Meteor Cam
Yerkes Observatory
est. 1892
Williams Bay, WI, USA
Yerkes Future Foundation
Largest refracting telescope in the world (1897)
First modern astrophysical observatory
Pioneer in adaptive optics
40-inch refractor (1m, 1897)
41-inch reflector (1m, 1968)
24-inch reflector (0.6m, 1964)
Amanda Bauer (deputy director)
Several of our facilities have virtual tours in video or interactive form. Below are links to these media:
