List of astronomical observatories
| Legend |
| Space observatory |
| Gravitational-wave detector| |
| Antimatter observatory| |
| Airborne observatory |
| Radio observatory |
| Microwave observatory |
| Ground-based observatory |
| Solar observatory |
| Neutrino detector |
| Cosmic-ray observatory |
| Educational observatory| |
This is a partial list of astronomical observatories ordered by name, along with initial dates of operation and location. The list also includes a final year of operation for many observatories that are no longer in operation. While other sciences, such as volcanology and meteorology, also use facilities called observatories for research and observations, this list is limited to observatories that are used to observe celestial objects.
Astronomical observatories are mainly divided into four categories: space-based, airborne, ground-based, and underground-based.
Many modern telescopes and observatories are located in space to observe astronomical objects in wavelengths of the electromagnetic spectrum that cannot penetrate the Earth's atmosphere and are thus impossible to observe using ground-based telescopes. Being above the atmosphere, these space observatories can also avoid the effects of atmospheric turbulence that plague ground based telescopes, although new generations of adaptive optics telescopes have since then dramatically improved the situation on the ground. The space high vacuum environment also frees the detectors from the ancestral diurnal cycle due to the atmospheric blue light background of the sky, thereby increasing significantly the observation time.
An intermediate variant is the airborne observatory, specialised in the infrared wavelengths of the electromagnetic spectrum, that conduct observations above the part of the atmosphere containing water vapor that absorbs them, in the stratosphere.
Historically, astronomical observatories consisted generally in a building or group of buildings where observations of astronomical objects such as sunspots, planets, asteroids, comets, stars, nebulae, and galaxies in the visible wavelengths of the electromagnetic spectrum were conducted. At first, for millennia, astronomical observations have been made with naked eyes. Then with the discovery of optics, with the help of different types of refractor telescopes and later with reflector telescopes. Their use allowed to dramatically increase both the collecting power and limit of resolution, thus the brightness, level of detail and apparent angular size of distant celestial objects allowing them to be better studied and understood. Following the development of modern physics, new ground-based facilities have been constructed to conduct research in the radio and microwave wavelengths of the electromagnetic spectrum, with radio telescopes and dedicated microwave telescopes.
Modern astrophysics has extended the field of study of celestial bodies to non-electromagnetic vectors, such as neutrinos, neutrons and cosmic rays or gravitational waves. Thus, new types of observatories have been developed. Interferometers are at the core of gravitational wave detectors. In order to limit the natural or artificial background noise, most particle detector based observatories are built deep underground.
Observatories
| Name | Established | Location |
| Abastumani Astrophysical Observatory | 1932 | Abastumani, Georgia |
| Abu Reyhan-e Birooni Observatory | 1976 | Shiraz University, Shiraz, Iran |
| Adirondack Public Observatory | Tupper Lake, New York, US | |
| Aditya-L1 | 2023 | Sun-Earth L1 |
| Adolphson Observatory | 2013 | Monmouth, Illinois, US |
| Airdrie Public Observatory | 1896 | Airdrie, Scotland, UK |
| Aker Observatory | 1995 | Safford, Arizona, US |
| Aldershot Observatory | 1906 | Aldershot, Hampshire, England, UK |
| Algonquin Radio Observatory | 1959 | Algonquin Provincial Park, Ontario, Canada |
| Allegheny Observatory | 1859 | Pittsburgh, Pennsylvania, US |
| Ametlla de Mar Observatory | 1992 | l'Ametlla de Mar, Catalonia, Spain |
| AMiBA | 2006 | Mauna Loa, Hawaii, US |
| Anderson Mesa Station | 1959 | Flagstaff, Arizona, US |
| Andrushivka Astronomical Observatory | 2001 | Andrushivka, Zhytomyr Oblast, Ukraine |
| Angell Hall Observatory | 1927 | Ann Arbor, Michigan, US |
| Ankara University Observatory | 1963 | Gölbaşı, Ankara, Turkey |
| Antarctic Muon and Neutrino Detector Array | 2002 | Antarctica |
| Antarctic Submillimeter Telescope and Remote Observatory | 1994–2005 | Antarctica |
| ANTARES | 2008 | In the Mediterranean Sea near Toulon, France |
| 2005 | Overgaard, Arizona, US | |
| Apache Point Observatory | 1985 | Sunspot, New Mexico, US |
| Apatity Cosmic-Ray Station | Apatity, Russia | |
| Apollo Observatory | 1969 | Dayton, Ohio, US |
| Arcetri Observatory | Arcetri, Florence, Italy | |
| Arecibo Observatory | 1963 | Arecibo, Puerto Rico, US |
| Argentine Institute of Radio Astronomy | 1966 | Berazategui Partido, Buenos Aires Province, Argentina |
| Armagh Observatory | 1790 | Armagh, UK |
| Aryabhatta Research Institute of Observational Sciences | 1954 | Nainital, Uttarakhand, India |
| Ashton Observatory | 1983 | Baxter, Iowa, US |
| Asiago Astrophysical Observatory | 1942 | Asiago, Italy |
| Assheton Observatory | 1860 | Lancashire, UK |
| ASTRON | 1949 | Dwingeloo, Netherlands |
| Astron ' | 1983–1989 | Highly eccentric Earth orbit |
| Astronomical Observatory Aurora | 2011 | Hechingen, Germany |
| Astronomical Observatory of Lisbon | 1867 | Lisbon, Portugal |
| Astronomy Centre | 1982 | Todmorden, England |
| Astronomy Tower of the Sorbonne | 1885–1909 | Paris, France |
| Astrophysical Institute Potsdam | 1992 | Potsdam, Germany |
| Atacama Pathfinder Experiment | 2003 | Llano de Chajnantor Observatory, Chile |
| Australia Telescope Compact Array | 1988 | Narrabri, Australia |
| Australian Astronomical Observatory | 1971 | Coonabarabran, Australia |
| Badlands Observatory | 2000 | Quinn, South Dakota, US |
| Baikal Deep Underwater Neutrino Telescope | 1993 | Baikal Lake, Russia |
| Bangladesh Astronomical Observatory | 2015 | Dhaka, Bangladesh |
| Baker Observatory | 1980 | Marshfield, Missouri, US |
| Baksan Neutrino Observatory | 1977 | Prielbrusye, Baksan Valley, Russia |
| Ball State University Observatory | Muncie, Indiana, US | |
| Barnard Observatory ' | 1859 | Oxford, Mississippi, US |
| Bareket Observatory | 1990 | Maccabim, Israel |
| Barnett Observatory | 1960 | Chesterfield, England, UK |
| Bayfordbury Observatory | 1969 | Hertfordshire, England, UK |
| Behlen Observatory | 1972 | Mead, Nebraska, US |
| Beijing Astronomical Observatory | 1958 | Beijing, China |
| Beijing Ancient Observatory | 1442 | Beijing, China |
| Belgrade Observatory | 1887 | Belgrade, Serbia |
| Belogradchik Observatory | 1961 | Belogradchik, Bulgaria |
| Benito Loyola Observatory | 2024 | Virginia Beach, Virginia, US |
| Benmore Peak Observatory | 1996 | Mackenzie Basin, South Island, New Zealand |
| BeppoSAX ' | 1996–2003 | Low Earth orbit |
| Bergisch Gladbach Observatory | 1995 | Bergisch Gladbach, Germany |
| Berlin Observatory | 1711 | Berlin, Germany |
| Besançon Observatory | 1882 | Besançon, France |
| Beverly-Begg Observatory | 1922 | Dunedin, South Island, New Zealand |
| Bidston Observatory | 1849 | Bidston, England, UK |
| Big Bear Lake Solar Observatory | 1969 | Big Bear City, California, US |
| Bisdee Tier Optical Astronomy Observatory | 2010 | Bisdee Tier, Spring Hill, Tasmania, Australia |
| Black Moshannon Observatory ' | 1972 | Pennsylvania, US |
| Blackett Observatory | 1930s | Wiltshire, England, UK |
| Blue Mesa Observatory ' | 1967 | New Mexico, US |
| 1987 | Boambee, New South Wales, Australia | |
| Bohyunsan Optical Astronomy Observatory | 1996 | Youngchun, South Korea |
| BOOTES | 1985 | Spain |
| Bordeaux Observatory | 1878 | Floirac, France |
| Bosscha Observatory | 1923 | Lembang, West Java, Indonesia |
| Boswell Observatory ' | 1883 | Crete, Nebraska, US |
| Bowman Observatory | 1940 | Greenwich, Connecticut, US |
| Boyden Observatory | 1889 | Bloemfontein, South Africa |
| Bradstreet Observatory | 1996 | St. Davids, Pennsylvania, US |
| Brackett Observatory | 1908 | Pomona College, Claremont, California, US |
| Bradley Observatory | 1950 | Decatur, Georgia, US |
| Braeside Observatory ' | 1976 | Flagstaff, Arizona, US |
| Brera Observatory | 1764 | Milan, Italy |
| Bridgewater State University Observatory | 2012 | Bridgewater, Massachusetts, US |
| Brooks Observatory | Toledo, Ohio, US | |
| Brooks Astronomical Observatory | 1964 | Mount Pleasant, Michigan, US |
| Brorfelde Observatory | 1953 | Holbæk, Denmark |
| Bucharest Astronomical Observatory | 1910 | Bucharest, Romania |
| Bucknell Observatory | Lewisburg, Pennsylvania, US | |
| Burrell Memorial Observatory | 1940 | Berea, Ohio, US |
| Byurakan Observatory | 1946 | Mount Aragats, Armenia |
| Cagigal Observatory | 1888 | Caracas, Venezuela |
| Cagliari Observatory | 1899 | Cagliari, Sardinia, Italy |
| Calais Observatory ' | 1857 | Calais, Maine, US |
| Calar Alto Observatory | 1975 | Almería, Spain |
| Caltech Submillimeter Observatory ' | 1986 | Mauna Kea, Hawaii, US |
| Cambridge Observatory | 1823 | Cambridge, UK |
| Camille Flammarion Observatory | 1883 | Juvisy-sur-Orge, France |
| Campbelltown Rotary Observatory | 2000 | Campbelltown, NSW, Australia |
| Campo Imperatore Near-Earth Object Survey | 2001 | Campo Imperatore, Italy |
| Canopus Hill Observatory | Hobart, Tasmania, Australia | |
| Capilla Peak Observatory | 1947 | Albuquerque, New Mexico, US |
| Capodimonte Observatory | 1812 | Naples, Italy |
| Carruthers Geocorona Observatory | 2025 | Earth–Sun L1 point |
| Carter Observatory | 1937 | Wellington, New Zealand |
| Catania Astrophysical Observatory | Catania, Italy | |
| Cawthron Atkinson Observatory | 1883 | Nelson, New Zealand |
| Celestial Observatory | Russellville, Arkansas, US | |
| Centennial Observatory | 2004 | Twin Falls, Idaho, US |
| Center for Astrophysics Harvard & Smithsonian | 1973 | Cambridge, Massachusetts, US |
| Cerro Armazones Observatory | 1995 | Atacama Desert, Chile |
| Cerro Tololo Inter-American Observatory | 1962 | Atacama Desert, Chile |
| Cerro Pachón Observatory | 2000 | Atacama Desert, Chile |
| Chabot Space & Science Center | 1883 | Oakland, California, US |
| Chamberlin Observatory | 1890 | Denver, Colorado, US |
| Changchun Astronomical Observatory | Changchun, Jilin Province, China | |
| Chandra X-ray Observatory | 1999 | Highly eccentric Earth orbit |
| Chianti Polifunctional Observatory | 2013 | San Donato in Poggio, Florence, Italy |
| Chico Community Observatory | 2001 | Chico, California, US |
| Chilbolton Observatory | 1967 | Chilbolton, UK |
| Cima Ekar Observing Station | 1966 | Asiago, Italy |
| Cincinnati Observatory | 1843 | Cincinnati, Ohio, US |
| City Observatory, Edinburgh | 1818 | Edinburgh, Scotland, UK |
| Clarke Observatory | 1897 / 1923 | Dunkirk, New York / Alliance, Ohio, US |
| Class of 1951 Observatory | 1997 | Poughkeepsie, New York, US |
| Cloudcroft Observatory ' | 1962 | New Mexico, US |
| Coats Observatory | 1883 | Paisley, Scotland, UK |
| Coit Observatory | Boston, Massachusetts, US | |
| Collins Observatory | 2003 | Corning, New York, US |
| Collm Observatory | Leipzig, Germany | |
| Colombo University Observatory | 1920s | Colombo, Sri Lanka |
| Compton Gamma-Ray Observatory ' | 1991–2000 | Low Earth orbit |
| ÇOMÜ Ulupınar Observatory | 2002 | Çanakkale, Turkey |
| Concordia College Observatory | Moorhead, Minnesota, US | |
| Consell Observatory | 1987 | Mallorca, Spain |
| Copenhagen University Observatory | 1861 | Copenhagen, Denmark |
| Cordell–Lorenz Observatory | Sewanee, Tennessee, US | |
| COROT | 2006 | Polar orbit |
| Cosmic Background Imager ' | 1999 | Llano de Chajnantor Observatory, Chile |
| Côte d'Azur Observatory | 1988 | France |
| Crane Observatory | Topeka, Kansas, US | |
| Crawford Observatory | 1880 | Cork, Ireland |
| Creighton University Observatory ' | 1886–1955 | Omaha, Nebraska, US |
| Crimean Astrophysical Observatory | 1945 | Nauchnyi, Crimea |
| Črni Vrh Observatory | 1975 | Idrija, Slovenia |
| Cupillari Observatory | La Plume, Pennsylvania, US | |
| Custer Observatory | 1927 | Southold, New York, US |
| & Observatory | 2023 | Nicosia, Cyprus |
| Daniel S. Schanck Observatory ' | 1865 | Rutgers University, New Brunswick, New Jersey, US |
| Daniel Scholl Observatory ' | 1886–1966 | Lancaster, Pennsylvania, US |
| Daocheng Solar Radio Telescope | 2022 | Daocheng County, Garze Tibetan Autonomous Prefecture, Sichuan Province, China. |
| Dark Sky Observatory | 1981 | Phillips Gap, Wilkes County, North Carolina, US |
| Dark Matter Particle Explorer | 2015 | 500 km LEO |
| Darling's Observatory ' | 1917 | Duluth, Minnesota, US |
| Dearborn Observatory | 1889 | Evanston, Illinois, US |
| Detroit Observatory | 1854 | Ann Arbor, Michigan, US |
| David Dunlap Observatory | 1935 | Richmond Hill, Ontario, Canada |
| Dome C | Antarctica | |
| Dominion Observatory | 1905 | Ottawa, Ontario, Canada |
| Dominion Astrophysical Observatory | 1918 | Saanich, British Columbia, Canada |
| Dominion Radio Astrophysical Observatory | 1960 | Kaleden, British Columbia, Canada |
| Dunsink Observatory | 1785 | Dublin, Ireland |
| Durham University Observatory | 1839 | Durham, UK |
| Dyer Observatory | 1953 | Brentwood, Tennessee, US |
| Effelsberg 100-m Radio Telescope | 1972 | Bonn, Germany |
| Ege University Observatory | 1965 | Kemalpaşa, İzmir, Turkey |
| Einstein Probe | 2024 | Low Earth orbit |
| Einstein Observatory ' | 1978 | Low Earth orbit |
| Elginfield Observatory | 1969 | Middlesex Centre, Ontario, Canada |
| 2004 | Sterling Hill Mining Museum, Ogdensburg, New Jersey, US | |
| Embry-Riddle Observatory | 2005 | Daytona Beach, Florida, US |
| Entoto Observatory Space Science Research Center | 2012 | Mount Entoto, Ethiopia |
| Eskdalemuir Observatory | 1908 | Dumfries and Galloway, Scotland, UK |
| Euclid Telescope | 2023 | Earth–Sun Lagrangian point |
| European Southern Observatory | Atacama Desert, Chile | |
| Fabra Observatory | 1906 | Barcelona, Spain |
| Fan Mountain Observatory | 1966 | Albemarle County, Virginia, US |
| Five-hundred-meter Aperture Spherical Radio Telescope | 2013 | Duyun, Pingtang County, Guizhou Province, China |
| Félix Aguilar Observatory | 1965 | San Juan, Argentina |
| Fernbank Observatory | Atlanta, Georgia, US | |
| Fermi Gamma-ray Space Telescope | 2008 | Low Earth orbit |
| Fick Observatory | 1966 | Boone, Iowa, US |
| Five College Radio Astronomy Observatory ' | 1976–2011 | New Salem, Massachusetts, US |
| Flarestar Observatory | San Gwann, Malta | |
| Foggy Bottom Observatory | 1951 | Hamilton, New York, US |
| Foothill Observatory | Los Altos Hills, California, US | |
| Ford Observatory | 1998 | Ithaca, New York, US |
| Fox Observatory | Sunrise, Florida, US | |
| Fox Park Public Observatory | 1999 | Potterville, Michigan, US |
| Francis Marion University Observatory | 1982 | Florence, South Carolina, US |
| Fred Lawrence Whipple Observatory | 1968 | Mount Hopkins, Arizona, US |
| Fremont Peak Observatory | 1986 | San Juan Bautista, California, US |
| Frosty Drew Observatory | 1980s | Charlestown, Rhode Island, US |
| Fuertes Observatory | 1917 | Ithaca, New York, US |
| Galaxy Evolution Explorer | 2003 | Caltech, Jet Propulsion Laboratory, California, US |
| Gaocheng Astronomical Observatory | 1276 | Dengfeng, Henan, China |
| Gauribidanur Radio Observatory | 1976 | Gauribidanur, Karnataka, India |
| Gemini Observatory | 1999 | Southern Operations Center: La Serena, Chile; Northern Operations Center: Hilo, Hawaii, US |
| George Observatory | 1989 | Brazos Bend State Park, near Houston, Texas, US |
| Giant Meterwave Radio Telescope | 1995 | Pune, Maharashtra, India |
| Gifford Observatory | 1912 | Wellington, New Zealand |
| Girawali Observatory | 2006 | Pune, Maharashtra, India |
| Glen D. Riley Observatory | 1973 | Naperville, Illinois, US |
| Godlee Observatory | 1902 | Manchester, England, UK |
| Goodsell Observatory | 1887 | Northfield, Minnesota, US |
| Goethe Link Observatory | 1939 | Brooklyn, Indiana, US |
| Goldendale Observatory | 1973 | Goldendale, Washington, US |
| Gornergrat ' | 1967–2005 | Gornergrat, Switzerland |
| Granat ' | 1989–1999 | Highly eccentric Earth orbit |
| Gran Telescopio Canarias | 2006 | Canary Islands, Spain |
| Grant O. Gale Observatory | 1984 | Grinnell, Iowa, US |
| Green Bank Telescope | 2000 | Green Bank, West Virginia, US |
| Green Point Observatory | 1961 | Sutherland, New South Wales, Australia |
| Grenfell Observatory | 2012 | Corner Brook, Newfoundland and Labrador, Canada |
| Griffith Observatory | 1935 | Los Angeles, California, US |
| Guillermo Haro Observatory | 1972 | Cananea, Sonora, Mexico |
| Gyarah Sidi | Agra, Uttar Pradesh, India | |
| HALCA ' | 1997–2005 | Elliptical Earth-centered orbit |
| Haleakala Observatory | Maui, Hawaii, US | |
| Halley Observatory | 1987 | Heesch, Netherlands |
| Hamburg Observatory | 1803 | Hamburg, Germany |
| Hat Creek Radio Observatory | 1950s | Shasta County, California, US |
| Hard Labor Creek Observatory | Atlanta, Georgia, US | |
| Space Hard X-Ray Modulation Telescope | 2017 | 550 km LEO |
| Hartung–Boothroyd Observatory | 1974 | Ithaca, New York, US |
| Hartebeesthoek Radio Astronomy Observatory | 1961 | Gauteng, South Africa |
| Hartwell House | 1831 | Hartwell, Buckinghamshire, UK |
| Harvard College Observatory | 1839 | Cambridge, Massachusetts, US |
| Haute-Provence Observatory | 1937 | Alpes-de-Haute-Provence, France |
| Haystack Observatory | 1964 | Westford, Massachusetts, US |
| Hector J Robinson Observatory | 1964 | Lincoln Park, Michigan, US |
| Helium and Lead Observatory | 2012 | Sudbury, Ontario, Canada |
| Helmos Observatory | 2007 | Mount Helmos, Greece |
| Helsinki University Observatory | 1834 | Helsinki/Kirkkonummi, Finland |
| Herrett Observatory | 2004 | Twin Falls, Idaho, US |
| Herschel Space Observatory | 2009 | Earth–Sun L2 point |
| Hidden Valley Observatory | 1960s | Rapid City, South Dakota, US |
| Hida Observatory, Kyoto University | 1968 | Takayama, Gifu, Japan |
| Heyden Observatory, Georgetown University | 1844 | Washington, D.C., US |
| High Altitude Water Cherenkov Observatory | 2015 | Sierra Negra, Puebla, Mexico |
| High Energy Stereoscopic System | 2002 | Khomas Region, Namibia |
| Highland Road Park Observatory | 1997 | Baton Rouge, Louisiana, US |
| Hinode | 2006 | Low Earth orbit |
| Hirsch Observatory | 1942 | Troy, New York, US |
| Hobbs Observatory | 1974 | Fall Creek, Wisconsin, US |
| Hoher List Observatory | 1954 | Daun, Germany |
| Holcomb Observatory and Planetarium | 1954 | Indianapolis, Indiana, US |
| Hong Kong Observatory | 1883 | Tsim Sha Tsui, Kowloon, Hong Kong |
| Hoober Observatory | 1993 | Rotherham, UK |
| Hopkins Observatory | 1838 | Williamstown, Massachusetts, US |
| Howell Observatory | Starkville, Mississippi, US | |
| Hradec Králové Observatory | 1961 | Hradec Králové, Czech Republic |
| Huairou Solar Observing Station | Beijing, China | |
| Hubble Space Telescope | 1990 | Low Earth orbit |
| Huggins Observatory defunct | 1856 | London, England, UK |
| Hume Cronyn Memorial Observatory | 1940 | London, Ontario, Canada |
| Hyde Memorial Observatory | 1977 | Lincoln, Nebraska, US |
| IceCube Neutrino Observatory | 2010 | Amundsen–Scott South Pole Station, Antarctica |
| Indian Astronomical Observatory | 2001 | Hanle, Ladakh, India |
| 2008 | Humble, Texas, US | |
| Instituto de Astrofísica de Canarias | 1975 | Canary Islands, Spain |
| INTEGRAL | 2002 | Highly eccentric Earth orbit |
| Infrared Astronomical Satellite ' | January–November 1983 | Earth orbit |
| Infrared Space Observatory ' | 1995–1998 | Earth orbit |
| Innsbruck Observatory | Innsbruck, Austria | |
| IRAM 30m telescope | 1984 | Pico Veleta, Spain |
| IRAM Plateau de Bure Interferometer | 1988 | Gap, Hautes-Alpes, France |
| Iranian National Observatory | 2017 | Mount Gargash, Iran |
| Isaac Newton Group of Telescopes | 1979 | La Palma, Spain |
| Isaac Roberts' Observatory ' | 1890 | Crowborough, UK |
| Iso-Heikkilä Observatory ' | 1935 | Turku, Finland |
| Constantinople Observatory of Taqi ad-Din | 1577 | Constantinople, Turkey |
| Istanbul University Observatory | 1936 | Istanbul, Turkey |
| Istituto Ricerche Solari Locarno, IRSOL | 1960 | Locarno, Switzerland |
| IXPE | 2021 | Earth orbit |
| Jack C. Davis Observatory | 2002 | Carson City, Nevada, US |
| Astronomical Observatory of the Jagiellonian University | 1792 | Kraków, Poland |
| James Clerk Maxwell Telescope | 1987 | Mauna Kea, Hawaii, US |
| James Gregory Telescope | 1962 | St. Andrews, UK |
| James Webb Space Telescope | 2021 | Earth–Sun Lagrangian point |
| James Wylie Shepherd Observatory | 2009 | Montevallo, Alabama, US |
| Jakarta Observatory | 1968 | Jakarta, Indonesia |
| Jantar Mantar | 1727 | Jaipur, Rajasthan, India |
| Jena Observatory | 1962 | Jena, Germany |
| Jewett Observatory | 1953 | Pullman, Washington, US |
| Jodrell Bank Observatory | 1945 | Cheshire, England, UK |
| JAC Johor Astronomy | 2014 | Johor, Malaysia |
| Jones Observatory | 1936 | Chattanooga, Tennessee, US |
| Jordan Hall of Science | 2006 | Notre Dame, Indiana, US |
| Judson B. Coit Observatory | Boston, Massachusetts, US | |
| KAIRA | 2011 | Kilpisjarvi, Finland |
| Khajeh Nasiredin Observatory | ~1980 | Tabriz University, Tabriz, Iran |
| Kamioka Observatory | 1983 | Hida, Gifu, Japan |
| Kanzelhoehe Solar Observatory | 1943 | Villach, Austria |
| Karl Schwarzschild Observatory | 1960 | Jena, Germany |
| Keck Observatory | 1993 | Mauna Kea, Hawaii, US |
| Keeble Observatory | 1963 | Ashland, Virginia, US |
| Keele | 1962 | Keele University, England, UK |
| Kennon Observatory | 1939 | Oxford, Mississippi, US |
| Kepler Space Observatory | 2009 | Earth-trailing heliocentric orbit |
| Kevola Observatory | 1963 | Kevola, Finland |
| Kielder Observatory | 2008 | Kielder Forest, Northumberland, England, UK |
| King's Observatory ' | 1769 | Greater London, England, UK |
| Kirkwood Observatory | 1901 | Bloomington, Indiana, US |
| Kiso Observatory | 1974 | Mount Ontake, Japan |
| Kitami Observatory | 1987 | Hokkaidō, Japan |
| Kitt Peak National Observatory | 1958 | Tucson, Arizona, US |
| Kleť Observatory | 1957 | České Budějovice, Czech Republic |
| Kodaikanal Solar Observatory | 1899 | Palani, Tamil Nadu, India |
| Konkoly Observatory | 1871 | Budapest, Hungary |
| Kopernik Observatory & Science Center | 1974 | Vestal, New York, US |
| KOSMA observatory | 1985–2010 | Gornergrat, Switzerland |
| Kottamia Astronomical Observatory | 1964 | Cairo Governorate, Egypt |
| Kryoneri Observatory | 1972 | Mount Kyllini, Greece |
| Kuffner observatory | 1884 | Vienna, Austria |
| Kuiper Airborne Observatory | 1974 | 14 km in the stratosphere |
| Kwasan Observatory, Kyoto University | 1929 | Kyoto, Japan |
| Kvistaberg Observatory | 1948 | Bro, Sweden |
| Kyung Hee Observatory | 1992 | Seoul, South Korea |
| Laboratoire d'Astrophysique de Grenoble | 2001 | Grenoble, France |
| Observatorio de La Cañada | 2002 | Ávila, Spain |
| Ladd Observatory | 1891 | Providence, Rhode Island, US |
| Lake Afton Public Observatory | 1979 | Wichita, Kansas, US |
| Lamont–Hussey Observatory ' | 1928 | Bloemfontein, South Africa |
| Landessternwarte Heidelberg-Königstuhl | 1898 | Königstuhl, Heidelberg, Germany |
| Landolt Astronomical Observatory | 1939 | Baton Rouge, Louisiana, US |
| La Plata Astronomical Observatory | 1883 | La Plata, Argentina |
| La Silla Observatory | 1969 | Atacama Desert, Chile |
| Large Binocular Telescope Observatory | 2005 | Mount Graham, Arizona, US |
| Large High Altitude Air Shower Observatory | 2019 | Daocheng County, Sichuan, China |
| Large Sky Area Multi-Object Fibre Spectroscopic Telescope | 2009 | Xinglong Station, Hebei, China |
| Large Millimeter Telescope | 2011 | Sierra Negra, Puebla, Mexico |
| Las Brisas Observatory | 1979 | Colorado, US |
| Las Campanas Observatory | La Serena, Chile | |
| Langkawi National Observatory | 2012 | Langkawi Island, Malaysia |
| Las Cumbres Observatory Global Telescope | 2005 | Global network |
| Laws Observatory | 1880 | Columbia, Missouri, US |
| Leander McCormick Observatory | 1885 | Mount Jefferson, Charlottesville, Virginia, US |
| Lee Observatory | 1873 | American University of Beirut, Beirut, Lebanon |
| Leiden Observatory | 1633 | Leiden University, Leiden, Netherlands |
| Leipzig Observatory | Leipzig, Germany | |
| Leoncito Astronomical Complex | 1986 | Calingasta, San Juan, Argentina |
| Levenhagen Observatory | Seattle, Washington, US | |
| Lick Observatory | 1881 | Mount Hamilton, San Jose, California, US |
| LightBuckets | 2007 | Rodeo, New Mexico, US |
| LIGO| | Hanford Site| & Livingston, Louisiana|, US | |
| Lindheimer Astrophysical Research Center ' | 1966–1995 | Evanston, Illinois, US |
| Llano de Chajnantor Observatory | 2005 | Atacama Desert, Chile |
| Llano del Hato National Astronomical Observatory | 1975 | Mérida, Venezuela |
| Lockyer Technology Centre | 2010 | Sidmouth, Devon, England, UK |
| Long Wavelength Array | 2010 | Socorro, New Mexico, US |
| Longa Vista Observatory | 2010 | Itatiba, SP, Brazil |
| Lowell Observatory | Flagstaff, Arizona, US | |
| Lucknow Observatory | 1832–1848 | Lucknow, India |
| Lulin Observatory | 1999 | Mount Lulin, Taiwan |
| Lund Observatory | 1749 | Lund, Sweden |
| Luoxue Mountain Cosmic Rays Research Center | 1953 | Luoxue Mountain, Yunnan Province, China |
| Lyon Observatory | 1878 | Saint-Genis-Laval, France |
| Macalester College Observatory | Saint Paul, Minnesota, US | |
| Macfarlane Observatory defunct | 1757 | Glasgow, Scotland, UK |
| Magdalena Ridge Observatory | 2006 | Socorro County, New Mexico, US |
| Mallorca Observatory | 1991 | Mallorca, Spain |
| Malakoff Tower | 1845 | Recife, Brazil |
| Manastash Ridge Observatory | 1972 | Ellensburg, Washington, US |
| Manuel Foster Observatory ' | 1903 | Santiago, Chile |
| Maragheh Observatory | 1259 | Maragheh, Iran |
| Margaret M. Jacoby Observatory | 1978 | Warwick, Rhode Island, US |
| Maria Mitchell Observatory | 1908 | Nantucket, Massachusetts, US |
| Marina Towers Observatory ' | 1989 | Maritime Quarter, Swansea, Wales, UK |
| Markree Observatory ' | 1837 | County Sligo, Ireland |
| Marseille Observatory | Marseille, France | |
| Martz Observatory | Chautauqua County, New York, US | |
| Mauna Kea Observatory | 1967 | Mauna Kea, Hawaii, US |
| Mauna Loa Solar Observatory | Hawaii, US | |
| Maynard F. Jordan Observatory | 1901 | Orono, Maine, US |
| McDonald Observatory | Davis Mountains, Texas, US | |
| McKim Observatory | 1884 | Greencastle, Indiana, US |
| McMath–Hulbert Solar Observatory | 1930 | Lake Angelus, Michigan, US |
| MDM Observatory | Kitt Peak, Arizona, US | |
| Mead Observatory | 2001 | Columbus, Georgia, US |
| Medicina Radio Observatory | 1965 | Medicina, Bologna, Italy |
| Mees Observatory | Rochester, New York, US | |
| Mehalso Observatory | Erie, Pennsylvania, US | |
| Melbourne Observatory | 1862 | Melbourne, Victoria, Australia |
| Melton Memorial Observatory | 1928 | Columbia, South Carolina, US |
| Mendenhall Observatory | 2002 | Stillwater, Oklahoma, US |
| Menke Observatory | 1994 | Davenport, Iowa, US |
| Metsähovi Observatory | 1966 | Kirkkonummi, Finland |
| Meudon Observatory | 1876 | Meudon, France |
| Meyer–Womble Observatory | 1996 | Mount Evans, Colorado, US |
| Michigan State University Observatory | 1969 | East Lansing, Michigan, US |
| Observatoire Midi-Pyrénées | ||
| Milagro | 1999 | Los Alamos, New Mexico, US |
| Miller Observatory | 1976 | Maiden, North Carolina, US |
| Mills Observatory | 1938 | Dundee, Scotland, UK |
| 2018 | Sebastian, Florida, US | |
| MMT Observatory | 1979 | Mount Hopkins, Arizona, US |
| Modine-Benstead Observatory | 1963 | Union Grove, Wisconsin, US |
| Modra Observatory | 1988 | Modra, Slovakia |
| Mohr Observatory ' | 1765–1780 | Jakarta, Indonesia |
| Moletai Astronomical Observatory | 1969 | Moletai, Lithuania |
| Molonglo Observatory Synthesis Telescope | 1960 | Bungendore, New South Wales, Australia |
| Mont Mégantic Observatory | 1978 | Mont Mégantic, Québec, Canada |
| Monterey Institute for Research in Astronomy | 1972 | Chews Ridge, California & Monterey, California, US |
| Montevideo National Observatory | Montevideo, Uruguay, | |
| Moore Observatory | 1978 | Oldham County, Kentucky, US |
| Morgan–Monroe Observatory | 1966 | Morgan–Monroe State Forest, Indiana, US |
| Morris Observatory | 1973 | North Manchester, Indiana, US |
| Morrison Observatory | Fayette, Missouri, US | |
| Moscow Cosmic-Ray Station | Troitsk, Russia | |
| Mount Stony Brook Observatory | 1968 | Stony Brook, New York, US |
| Mounds Observatory | Tulsa, Oklahoma, US | |
| Mount Abu InfraRed Observatory | 1995 | Mount Abu, Rajasthan, India |
| Mount Burnett Observatory | 1972 | Mount Burnett, Victoria, Australia |
| Mount Cuba Astronomical Observatory | Greenville, Delaware, US | |
| Mount Graham International Observatory | 1993 | Mount Graham, Arizona, US |
| Mount John University Observatory | 1965 | Lake Tekapo, South Island, New Zealand |
| Mount Laguna Observatory | 1968 | San Diego, California, US |
| Mount Lemmon Observatory | Tucson, Arizona, US | |
| Mount Pleasant Radio Observatory | Tasmania, Australia | |
| Mount Stromlo Observatory | 1911 | Canberra, Australia |
| Mount Suhora Observatory | 1987 | Gorce Mountains, Poland |
| Mount Wilson Observatory | 1904 | Mount Wilson, Los Angeles County, California, US |
| Mountain Skies Observatory | 1997 | Lyman, Wyoming, US |
| Mullard Radio Astronomy Observatory | 1957 | Cambridge, England, UK |
| Murchison Radio-astronomy Observatory | 2012 | Murchison, Western Australia, Australia |
| Mykolaiv Astronomical Observatory | 1821 | Mykolaiv, Mykolaiv Oblast, Ukraine |
| Nachi-Katsuura Observatory | Nachikatsuura, Wakayama, Japan | |
| Nançay Radio Telescope | 1965 | Nançay, France |
| Nanjing Astronomical Instruments Research Centre | 1958 | Nanjing, Jiangsu Province, China |
| National Astronomical Observatory | 1803 | Bogotá, Colombia |
| National Astronomical Observatory of Japan | 1988 | Headquarters: Mitaka, Tokyo, Japan |
| National Astronomical Observatory | 1967 | Sierra San Pedro Mártir, Baja California, Mexico |
| National Observatory | 1827 | Rio de Janeiro, Brazil |
| National Observatory of Athens | 1842 | Athens, Greece |
National Optical Astronomy Observatory
| Observatory, Cape Town, South Africa | |
| Southern Astrophysical Research Telescope | 2004 | Cerro Pachón, Chile |
| South Pole Telescope | 2007 | Antarctica |
| Spanish National Observatory | 1790 | Madrid, Spain |
| Special Astrophysical Observatory of the Russian Academy of Sciences | 1966 | Zelenchukskaya, near Arkhyz, Caucasus Mountains, Russia |
| Sperry Observatory | 1967 | Cranford, New Jersey, US |
| SPHEREx | 2025 | Sun-synchronous Earth orbit |
| Spitzer Space Telescope | 2003 | Heliocentric orbit |
| Springfield Observatory | 1968 | Springfield, Massachusetts, US |
| Sproul Observatory | 1911 | Swarthmore, Pennsylvania, US |
| Stardome Observatory | 1967 | Auckland, North Island, New Zealand |
| Starkenburg Observatory | 1970 | Heppenheim, Germany |
| Štefánik's Observatory | 1928 | Prague, Czech Republic |
| Stellafane Observatory | 1920 | Springfield, Vermont, US |
| 2019 | Kanab, Utah, US | |
| 1901 | Hiram, Ohio, US | |
| Steward Observatory | 1844 | Washington, D.C., US |
| Valongo Observatory | 1881 | Rio de Janeiro, Brazil |
| Vainu Bappu Observatory | 1968 | Kavalur, Tamil Nadu, India |
| Astronomical observatory of Aosta Valley | 2003 | Nus, Aosta Valley, Italy |
| Van Vleck Observatory | 1914 | Middletown, Connecticut, US |
| Vanderbilt University Observatory | Nashville, Tennessee, US | |
| Vartiovuori Observatory ' | 1819–1834 | Turku, Finland |
| Vassar College Observatory ' | 1865 | Poughkeepsie, New York, US |
| Vatican Observatory | Headquarters: Castel Gandolfo, Italy |