Historic observatories are places of awe and discovery where modern astronomy was born, and humankind’s understanding of the physical universe emerged.
The Alliance of Historic Observatories acts as a global collaboration of astronomical observatories and institutions in research, inspiration and engagement, and preservation of historic resources.
The Alliance of Historic Observatories (AHO) is a geographically diverse association of historic (> 50 years old) astronomical observatories that have played pivotal roles in advancing our understanding of the cosmos, today brought together by common objectives and challenges.
The purpose of the Alliance is to address the needs of its member organizations and professionals working in fields related to historic observatories such as conservation of historic instruments and buildings, history research, modern research applications for heritage equipment and public education.
Develop strategies for preserving and sharing our legacies with future generations.
Share methods to preserve the infrastructure of historic observatories.
Tell our stories as a model for how the observatories inspire people around the world to foster greater literacy in science.
Become model institutions of youth STEM programs.
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
Mount Wilson Observatory
est. 1904
Mt. Wilson, CA, USA
Mount Wilson Institute
Largest telescopes in the world (1908 and 1917)
First extragalactic distance measurements
Early cosmic expansion estimates
First evidence of dark matter
Discovery of different stellar populations
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
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)
AHO observatories meet every fall, typically for a couple of days, to discuss and plan alliance matters, exchange ideas, share experiences, and celebrate the achievements of our members. Lowell Observatory will host the next meeting in late September 2025. More information forthcoming.
From Tuesday 26 to Friday 29 August, 2025, McDonald Observatory will host a meeting for AHO member organization staff and volunteers who work in public programs to share ideas, resources, and best practices. Follow this link for details.
