# 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 (where an accurate date is available) 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 (such as ultraviolet radiation, X-rays, and gamma rays) 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 |
| Apache-Sitgreaves Observatory | 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 (defunct) | 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 (only for amateur use since 1980) | Paris, France |
| Astrophysical Institute Potsdam | 1992 | Potsdam, Germany |
| Atacama Pathfinder Experiment (APEX) | 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 (defunct) | 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 (defunct) | 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 (defunct) | 1972 | Pennsylvania, US |
| Blackett Observatory | 1930s | Wiltshire, England, UK |
| Blue Mesa Observatory (defunct) | 1967 | New Mexico, US |
| Boambee Observatory | 1987 | Boambee, New South Wales, Australia |
| Bohyunsan Optical Astronomy Observatory (BOAO) | 1996 | Youngchun, South Korea |
| BOOTES | 1985 | Spain |
| Bordeaux Observatory | 1878 | Floirac, France |
| Bosscha Observatory | 1923 | Lembang, West Java, Indonesia |
| Boswell Observatory (defunct) | 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 (defunct) | 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 (defunct) | 1857 | Calais, Maine, US |
| Calar Alto Observatory | 1975 | Almería, Spain |
| Caltech Submillimeter Observatory (defunct) | 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 |
| 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 (defunct) | 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 (defunct) | 1991–2000 | Low Earth orbit |
| ÇOMÜ Ulupınar Observatory | 2002 | Çanakkale, Turkey |
| Concordia College Observatory | | Moorhead, Minnesota, US |
| Consell Observatory | 1987 | Majorca, Spain |
| Copenhagen University Observatory | 1861 | Copenhagen, Denmark |
| Cordell–Lorenz Observatory | | Sewanee, Tennessee, US |
| COROT | 2006 | Polar orbit |
| Cosmic Background Imager (CBI) (defunct) | 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 (defunct) | 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 |
| The Cyprus Planetarium & Observatory | 2023 | Nicosia, Cyprus |
| Daniel S. Schanck Observatory (defunct) | 1865 | Rutgers University, New Brunswick, New Jersey, US |
| Daniel Scholl Observatory (defunct) | 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 (DAMPE) | 2015 | 500 km LEO |
| Darling's Observatory (defunct) | 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 (defunct) | 1978 | Low Earth orbit |
| Elginfield Observatory | 1969 | Middlesex Centre, Ontario, Canada |
| Ellis Observatory | 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 L$_2$ Lagrangian point |
| European Southern Observatory La Silla Observatory New Technology Telescope Llano de Chajnantor Observatory Very Large Telescope Paranal Observatory European Extremely Large Telescope | 1962 1969 1989 2005 1998 1999 2026 | 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 (defunct) | 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 (GALEX) | 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 (GMRT) | 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 (HFSJG) (defunct) | 1967–2005 | Gornergrat, Switzerland |
| Granat (defunct) | 1989–1999 | Highly eccentric Earth orbit |
| Gran Telescopio Canarias | 2006 | Canary Islands, Spain |
| Grant O. Gale Observatory | 1984 | Grinnell, Iowa, US |
| Green Bank Telescope | | 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 (defunct) | 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 (HXMT) | 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 |
| Insperity Observatory | 2008 | Humble, Texas, US |
| Instituto de Astrofísica de Canarias | 1975 | Canary Islands, Spain |
| INTEGRAL | 2002 | Highly eccentric Earth orbit |
| Infrared Astronomical Satellite (IRAS) (defunct) | January–November 1983 | Earth orbit |
| Infrared Space Observatory (ISO) (defunct) | 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 |
| Isasc Roberts' Observatory (defunct) | 1890 | Crowborough, UK |
| Iso-Heikkilä Observatory (defunct) | 1935 (only amateur use since 1972) | 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 L$_2$ 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 Observatory | 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 (defunct) | 1769 | Greater London, England, UK |
| Kirkwood Observatory | 1901 | Bloomington, Indiana, US |
| 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 (retired) | 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 (La Cañada Observatory) | 2002 | Ávila, Spain |
| Ladd Observatory | 1891 | Providence, Rhode Island, US |
| Lake Afton Public Observatory | 1979 | Wichita, Kansas, US |
| Lamont–Hussey Observatory (defunct) | 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 High Altitude Air Shower Observatory (LHAASO) | 2019 | Daocheng County, Sichuan, China |
| Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) | 2009 | Xinglong Station, Hebei, China |
| Large Millimeter Telescope | | 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 (commercial observatory) | 2007 | Rodeo, New Mexico, US |
| LIGO | 1999 | Hanford Site, Washington, US & Livingston, Louisiana, US, US |
| Lindheimer Astrophysical Research Center (defunct) | 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 Anderson Mesa Station | 1894 1959 | Flagstaff, Arizona, US |
| Lucknow (King of Oudh's) 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 Magdalena Ridge Observatory Single Telescope Magdalena Ridge Observatory Interferometer | 2006 2008 Under construction | Socorro County, New Mexico, US |
| Majorca Observatory | 1991 | Majorca, Spain |
| Malakoff Tower | 1845 | Recife, Brazil |
| Manastash Ridge Observatory | 1972 | Ellensburg, Washington, US |
| Manuel Foster Observatory (defunct) | 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 (Not In Use) | 1989 | Maritime Quarter, Swansea, Wales, UK |
| Markree Observatory (defunct) | 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 Pic du Midi Observatory Toulouse Observatory | 1878 1733 | Headquarters: Toulouse, France Pyrenees, France Toulouse, France |
| Milagro | 1999 | Los Alamos, New Mexico, US |
| Miller Observatory | 1976 | Maiden, North Carolina, US |
| Mills Observatory | 1938 | Dundee, Scotland, UK |
| Mind's Eye Observatory IAU W42 | 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 (demolished) | 1765–1780 | Jakarta, Indonesia |
| Moletai Astronomical Observatory | 1969 | Moletai, Lithuania |
| Molonglo Observatory Synthesis Telescope (MOST) | 1960 | Bungendore, New South Wales, Australia |
| Mont Mégantic Observatory | 1978 | Mont Mégantic, Québec, Canada |
| Monterey Institute for Research in Astronomy (Oliver Observing Station) | 1972 (1984) | Chews Ridge, California & Monterey, California, US |
| Montevideo National Observatory | | Montevideo, Uruguay, 34°54.6′S 56°12.8′W﻿ / ﻿34.9100°S 56.2133°W﻿ / -34.9100; -56.2133 |
| 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 (Colombia) | 1803 | Bogotá, Colombia |
| National Astronomical Observatory of Japan | 1988 | Headquarters: Mitaka, Tokyo, Japan |
| National Astronomical Observatory (Mexico) | 1967 | Sierra San Pedro Mártir, Baja California, Mexico |
| National Observatory (Brazil) | 1827 | Rio de Janeiro, Brazil |
| National Observatory of Athens | 1842 | Athens, Greece |
| National Optical Astronomy Observatory Cerro Tololo Inter-American Observatory Gemini Observatory Kitt Peak National Observatory National Solar Observatory | 1982 | Headquarters: Tucson, Arizona, US |
| National Optical Observatory | | Turkey |
| National Radio Astronomy Observatory Atacama Large Millimeter Array Green Bank Telescope Very Large Array Very Long Baseline Array | 1957 | Headquarters: Charlottesville, Virginia, US |
| National Research Institute of Astronomy and Geophysics (NRIAG) | 1903 | Helwan, Egypt |
| National Solar Observatory | 1952 | Sunspot, New Mexico, US & Kitt Peak, Arizona, US |
| Naval Research Lab. Radio Sta. | | Sugar Grove, West Virginia, US 38°31.2′N 79°16.4′W﻿ / ﻿38.5200°N 79.2733°W﻿ / 38.5200; -79.2733 |
| Naylor Observatory | 1971 | Harrisburg, Pennsylvania, US |
| Neuchâtel Observatory | 1858 | Neuchâtel, Switzerland |
| Nha Trang Observatory | 2017 | Nha Trang, Vietnam |
| Nice Observatory | 1879 | Nice, France |
| Nieuwland Hall (Napoleon III Telescope) | 1959 | Notre Dame, Indiana, US |
| Nizamia Observatory | 1907 | Hyderabad, India |
| Nordic Optical Telescope | 1988 | Canary Islands, Spain |
| Norilsk Cosmic-Ray Station | | Norilsk, Krasnoyarsk Krai, Russia |
| Norman Lockyer Observatory | 1912 | Sidmouth, UK |
| Northern Arizona University Observatory | | Flagstaff, Arizona, US |
| Northern Skies Observatory | 2009 | Peacham, Vermont, US |
| Northolt Branch Observatory | 2015 | London, England, UK |
| Northolt Branch Observatory 2, Shepherd's Bush | 2016 | London, England, UK |
| Northolt Branch Observatory 3, Blandford Forum | 2017 | London, England, UK |
| North Georgia Astronomical Observatory | | Dahlonega, Georgia, US |
| North Otago Astronomical Society Observatory | | Oamaru, South Island, New Zealand |
| Nyrölä Observatory | 1997 | Jyväskylän maalaiskunta, Western Finland Province, Finland |
| OAC (Observatorio Astronómico de Córdoba) | 1871 | Córdoba, Argentina |
| OAO (Observatorio de Aras de los Olmos) | 2008 | Aras de los Olmos, Valencia, Spain |
| O'Brien Observatory | 1961 | Marine on St. Croix, Minnesota, US |
| Observatoire du Pic de Château-Renard | 1974 | Saint-Véran, France |
| Observatorio Astronómico Nacional (Colombia) | 1803 | Bogotá, Colombia |
| Observatorio Astronomico Nacional Tonantzintla | 1961 | Tonantzintla, Mexico |
| Observatorio Solar Carl Sagan | 2000 | Hermosillo, Sonora, Mexico |
| Observatory House (defunct) | 1789 | Slough, UK |
| Observatory of the rue Serpente (defunct) | 1890–1968 | Paris, France |
| Oil Region Astronomical Observatory | | Venango County, Pennsylvania, US |
| Onan Observatory | 1990 | Norwood Young America, Minnesota, US |
| Ondokuz Mayıs University Observatory | 2006 | Samsun, Turkey |
| Ondřejov Observatory | 1898 | Ondřejov, Czech Republic |
| Onsala Space Observatory | 1949 | Onsala, Sweden |
| Ooty Radio Telescope | 1970 | Ooty, Tamil Nadu, India |
| Orchard Hill Observatory | 1965 | Amherst, Massachusetts, US |
| Orioloromano Observatory | 2007 | Oriolo Romano, Italy |
| Orion 1 (defunct) | 1971 | Low Earth orbit |
| Orion 2 (defunct) | 1973 | Low Earth orbit |
| Orion Ranch Observatory | 2009 | Bertram, Texas, US |
| Orwell Park School Observatory | 1848 | Nacton, UK |
| Ostrowik Observatory | 1952 | Ostrowik, Poland |
| Otter Creek Observatory | 1995 | Meade County, Kentucky, US |
| Oulu Cosmic-Ray Station | | Oulu, Finland |
| Owens Valley Radio Observatory | 1958 | Bishop, California, US |
| Pachmarhi Array of Cerenkov Telescopes (PACT) | 1986 | Pachmarhi, Madhya Pradesh, India |
| Palisades-Dows Observatory | 1987 | Cedar Rapids, Iowa, US |
| PAGASA Astronomical Observatory | 1954 | Quezon City, Philippines |
| Palermo Observatory | 1790 | Palermo, Sicily, Italy |
| Palomar Observatory | 1948 | Palomar Mountain, California, US |
| Panzano Observatory | 1640 | Bologna, Italy |
| Paranal Observatory | 1999 | Cerro Paranal, Atacama Desert, Chile |
| Paris Observatory | 1667 | Paris, France |
| Parkes Observatory | 1961 | Parkes, Australia |
| Paul Robinson Observatory | 1965 | High Bridge, New Jersey, US |
| Peach Mountain Observatory | 1950 | Dexter, Michigan, US |
| Penteli Observatory | 1937 | Penteli, Attica, Greece |
| Perkins Observatory | 1931 | Delaware, Ohio, US |
| Perth Observatory | 1896 | Perth, Australia |
| Peterberg Observatory | 1977 | Saarland, Germany |
| Pic du Midi Observatory | 1878 | Pic du Midi, Pyrenees, France |
| Pico dos Dias Observatory | 1981 | Minas Gerais, Brazil |
| Piera Observatory | 1968 | Barcelona, Spain |
| Pierre Auger Observatory | 2004 | Malargüe, Argentina |
| Pine Bluff Observatory | 1958 | Cross Plains, Wisconsin, US |
| Pine Mountain Observatory | 1965 | Bend, Oregon, US |
| Pistoia Mountains Astronomical Observatory | 1990 | Pian dei Termini (near San Marcello Pistoiese), Italy |
| Piwnice Ovservatory | 1945 | Piwnice near Toruń, Poland |
| Planetarium and Astronomical Observatory in Grudziądz | 1972 | Grudziądz, Kujawsko-Pomorskie, Poland |
| Plateau Astronomique de La Couronne | 2024 | Cordes-sur-Ciel, Tarn, France |
| Pollock Astronomical Observatory | 2004 | Hunting Valley, Ohio, US |
| Portage Lake Observatory (defunct) | 1948 | Dexter, Michigan, US |
| Poznań Observatory | 1919 | Poznań, Poland |
| Prishtina Observatory | 1997 | Pristina Municipality, Kosovo |
| PROBA-3 | 2024 | Low Earth orbit |
| Puckett Observatory | 1977 | Ellijay, Georgia, US |
| Pula Observatory | 1869 | Pula, Croatia |
| Pulkovo Observatory | 1839 | Pulkovskiye Heights, Russia |
| Purple Mountain Observatory | 1929 | Nanjing, Jiangsu Province, China |
| Queqiao | 2018 | Earth-Moon L$_2$ |
| Queqiao-2 | 2024 | Lunar orbit |
| Quito Astronomical Observatory | 1873 | La Alameda Park, Quito, Ecuador |
| Radcliffe Observatory | 1772 | Oxford, England. Moved to Durban, South Africa in 1939 |
| Rainwater Observatory | | French Camp, Mississippi, US |
| Ralph A. Worley Observatory | 1964 | Shreveport, Louisiana, US |
| Rankin Science Observatory | 1963 | Appalachian State University, Boone, North Carolina, US |
| Rancho Mirage Library and Observatory | 2018 | Rancho Mirage, California, US |
| Rattlesnake Mountain Observatory (defunct) | 1971 | Hanford Reach National Monument, Washington, US |
| Real Instituto y Observatorio de la Armada (Spain) | 1793 | San Fernando, Cádiz, Spain |
| Red Barn Observatory | 2006 | Ty Ty, Georgia, US |
| Red Buttes Observatory | 1994 | Laramie, Wyoming, US |
| Riley Observatory | 1974 | Naperville, Illinois, US |
| RIT Observatory | | Rochester, New York, US |
| Ritter Observatory | | Toledo, Ohio, US |
| Robert A. Schommer Observatory | | Rutgers University, New Brunswick, New Jersey, US |
| Robert Brownlee Observatory | | Lake Arrowhead, California, US |
| Robinson Observatory | | Orlando, Florida, US |
| Robotic Lunar Observatory (defunct) | 1995 | Flagstaff, Arizona, US |
| Roger Twitchell Observatory | 1972 | Paris, Maine, US |
| Rogers Observatory | 1981 | Traverse City, Michigan, US |
| Rolnick Observatory | | Westport, Connecticut, US |
| Rome Observatory | 1938 | Italy |
| Roseland Observatory | 1998 | St Stephen-in-Brannel, UK |
| Rossall School Observatory | | Rossall, UK |
| Rothney Astrophysical Observatory | 1984 | Priddis, Alberta, Canada |
| Royal Observatory, Greenwich | 1675 | Greenwich, England, UK |
| Royal Observatory, Edinburgh | 1896 | Edinburgh, Scotland, UK |
| Roque de los Muchachos Observatory | 1979 (officially inaugurated in 1985) | La Palma, Canary Islands, Spain. |
| Rosemary Hill Observatory | | Bronson, Florida, US |
| Rozhen Observatory | 1981 | Peak Rozhen, Bulgaria |
| Rutherford Observatory | 1920s | New York City, New York, US |
| San Fernando Observatory (SFO) | 1976 | Sylmar, California, US |
| Sankt Andreasberg Observatory | 2014 | Sankt Andreasberg, Germany |
| Sayan Spectrographic Cosmic Ray Complex | | Irkutsk, Russia |
| SFA Observatory | 1976 | Nacogdoches, Texas, US |
| Sagamore Hill Radio Observatory | 1963 | Hamilton, Massachusetts, US |
| Shattuck Observatory | 1854 | Hanover, New Hampshire, US |
| Sherwood Observatory | 1972 | Mansfield, UK |
| Seven Hills Observatory | 1996 | Kearney, Nebraska, US |
| Shamakhi Astrophysical Observatory | 1958 | Shamakhi, Azerbaijan |
| Shanghai Astronomical Observatory | 1962 | Shanghai, China |
| Sherzer Observatory | 1878 | Ypsilanti, Michigan, US |
| Sheshan Astronomical Observatory | 1900 | Shanghai, China |
| Siding Spring Observatory | 1924 | Siding Spring, New South Wales, Australia |
| Sidmouth Observatory | 1912 | Sidmouth, Devon, England, UK |
| Sierra Nevada Observatory | 1981 | Sierra Nevada, Spain |
| Silesian Planetarium and Astronomical Observatory | 1955 | Chorzów / Katowice, Silesia, Poland |
| Simeiz Observatory | 1906 | Simeiz, Crimea, Ukraine |
| Skalnaté Pleso Observatory | 1953 | Vysoké Tatry, Slovakia |
| Skinakas Observatory | 1984 | Crete, Greece |
| Skylab | 1973 | Low Earth orbit; re-entered in 1979 |
| Smith Observatory | 1880s | Beloit, Wisconsin, US |
| Smithsonian Astrophysical Observatory | 1890 | Cambridge, Massachusetts, US |
| Sobaeksan Optical Astronomy Observatory | 1978 | Sobaeksan, South Korea |
| Sola Fide Observatory | 1990s | Austin, Minnesota, US |
| Solar and Heliospheric Observatory (SOHO) | 1996 | Earth–Sun L1 point |
| Solar Space Telescope | 2009 | 709 km SSO; life: 3 years |
| Sommers–Bausch Observatory | 1949 | Boulder, Colorado, US |
| Sonnenborgh Observatory | 1853 | Utrecht, Netherlands |
| Sonoma State Observatory | 1976 | Rohnert Park, California, US |
| South African Astronomical Observatory Cape Town Sutherland | 1820 1972 | Observatory, Cape Town, South Africa Sutherland, Northern Cape, South Africa |
| Southern Astrophysical Research Telescope (SOAR) | 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 |
| Stellar Vista Observatory | 2019 | Kanab, Utah, US |
| Stephens Memorial Observatory | 1901 | Hiram, Ohio, US |
| Steward Observatory MMT Observatory Mount Graham International Observatory Mount Lemmon Observatory | 1916 | Tucson, Arizona, US |
| Stickney Observatory | 1950s | Bennington, Vermont, US |
| Stjerneborg | 1581 | Hven, Sweden |
| Stockholm Observatory | 1749 | Stockholm, Sweden |
| Stokesville Observatory | 1970s | Virginia, US |
| Stone Observatory | 1853 | Stone, Buckinghamshire, UK |
| Stonyhurst Observatory | 1838 | Lancashire, England |
| Strasbourg Observatory | 1881 | Strasbourg, France |
| Stratospheric Observatory for Infrared Astronomy | 2006 | 14 km in Earth stratosphere |
| Stull Observatory | 1966 | Alfred, New York, US |
| Stuttgart Observatory | 1920 | Stuttgart, Germany |
| Submillimeter Array | 1987 | Mauna Kea, Hawaii, US |
| St. Thomas Observatory | 2009 | Saint Paul, Minnesota, US |
| Space Variable Objects Monitor | 2004 | Low Earth orbit |
| Sudbury Neutrino Observatory | 1999 | Sudbury, Ontario, Canada |
| Sunriver Observatory | 1990 | Sunriver, Oregon, US |
| Swift Gamma-Ray Burst Mission | 2004 | Low Earth orbit |
| Swiss Observatory Polychron and Astronomy | 2019 | Geneva, Switzerland |
| Sydney Observatory | 1858 | Sydney, Australia |
| Table Mountain Observatory | | Angeles National Forest, Wrightwood, California, US |
| Tacubaya Observatory | 1882 | Tacubaya, Mexico City, Mexico |
| Taeduk Radio Astronomy Observatory | 1986 | Taejon, South Korea |
| Tamke-Allan Observatory | 1998 | Roane County, Tennessee, US |
| Tartu Observatory | 1964 | Tartumaa, Estonia |
| Teide Observatory | 1964 | Tenerife, Canary Islands, Spain |
| Ten Acre Observatory | | Tribbey, Oklahoma, US |
| Terskol Peak Observatory | 1989 | Terskol, Kabardino-Balkaria, Russia |
| Thai National Observatory | 2013 | Doi Inthanon, Chiang Mai, Thailand |
| The Dam Observatory | 2017 | Lake Tschida, North Dakota, US |
| The Heights Observatory | 1989 | The Heights School, South Australia, Australia |
| Texas A&M Astronomical Observatory | | College Station, Texas, US |
| Theodore Jacobsen Observatory | 1895 | Seattle, Washington, US |
| Thompson Observatory | 1968 | Beloit, Wisconsin, US |
| Tien Shan Astronomical Observatory | | Almaty, Kazakhstan |
| Tuorla Observatory | 1952 | Piikkiö, Finland |
| Trieste Observatory | | Trieste, Italy |
| Troodos Observatory | 2023 | Agridia, Troodos Mountains, Cyprus |
| Trottier Observatory | 2015 | Simon Fraser University, Burnaby, Canada |
| Turin Observatory | 1759 | Pino Torinese, Italy |
| Udaipur Solar Observatory | | Udaipur, Rajasthan, India |
| Ukrainian T-shaped Radio telescope, second modification | 1972 | Shevchenkove, Ukraine |
| Ulugh Beg Observatory | 1420s | Samarkand, Uzbekistan |
| University of Alabama Observatory | 1950 | Tuscaloosa, Alabama, US |
| University of Alabama Observatory (Old) | 1849–1890s | Tuscaloosa, Alabama, US |
| University of North Alabama Observatory | | Florence, Alabama, US |
| University of Illinois Astronomical Observatory | 1896 | Urbana, Illinois, US |
| University of London Observatory | 1929 | London, England, UK |
| University of Maryland Observatory | | College Park, Maryland, US |
| University of Michigan-Dearborn Observatory | 2007 | Dearborn, Michigan, US |
| University of New Hampshire Observatory | 1985 | Durham, New Hampshire, US |
| University of Oklahoma Observatory | | Norman, Oklahoma, US |
| University of Puerto Rico at Humacao Observatory | 1985 | Humacao, Puerto Rico, US |
| University of Valencia Astronomical Observatory | 1909 | Valencia, Spain |
| Uppsala Astronomical Observatory | 1741 | Uppsala, Sweden |
| Urania (Antwerp) | | Hove, Belgium |
| Urania (Berlin) | | Berlin, Germany |
| Urania (Vienna) | 1909 | Vienna, Austria |
| Urania Observatory (Zürich) | 1907 | Zürich, Switzerland |
| Uraniborg | 1572–1597 (demolished) | Hven, Sweden |
| Urumqi Astronomical Observatory | 1957 | Urumqi, Xinjiang, China |
| U.S. Naval Observatory (USNO) Depot of Charts and Instruments (U.S. Navy) (precursor, renamed to USNO) U.S. Naval Observatory (Flagstaff Station) | 1844 1830–1844 1955 | Washington, D.C., US Washington, D.C., US Flagstaff, Arizona, 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 (defunct) | 1819–1834 | Turku, Finland |
| Vassar College Observatory (defunct) | 1865 | Poughkeepsie, New York, US |
| Vatican Observatory Vatican Advanced Technology Telescope | 1891 1993 | Headquarters: Castel Gandolfo, Italy Mount Graham, Arizona, US |
| Veen Observatory | 1970 | Lowell, Michigan, US |
| Vega–Bray Observatory | 1990 | Benson, Arizona, US |
| Ventspils Starptautiskais Radioastronomijas Centrs | | Irbene, Latvia |
| Vernonia Peak Observatory | | Vernonia, Oregon, US |
| Very Large Array | 1980 | Socorro, New Mexico, US |
| Very Long Baseline Array | 1993 | Various locations on Earth |
| Vienna Observatory | 1753 | Vienna, Austria |
| Vilnius University Observatory | 1753 | Vilnius University, Lithuania |
| Višnjan Observatory | 1978 | Višnjan, Croatia |
| Vsetín Observatory | 1950 | Vsetín, Czech Republic |
| Warkworth Radio Observatory | 2008 | Warkworth, New Zealand |
| Warner Observatory (defunct) | 1882 | Rochester, New York, US |
| Warner and Swasey Observatory | 1919 | Cleveland, Ohio, US |
| Warren Rupp Observatory | 1985 | Mansfield, Ohio, US |
| University of Warsaw Observatory | 1825 | Warsaw, Poland |
| Washburn Observatory | 1881 | Madison, Wisconsin, US |
| Wast Hills Observatory | 1982 | Birmingham, England, UK |
| Weaver Student Observatory | 1998 | Monterey, California, US |
| Weitkamp Observatory | 1955 | Westerville, Ohio, US |
| West Mountain Observatory | 1981 | West Mountain, Utah, US |
| Whakatane Astronomical Society | 1964 | Whakatāne, New Zealand |
| Whitin Observatory | 1901 | Wellesley, Massachusetts, US |
| Widener University Observatory | 2004 | Chester, Pennsylvania, US |
| Wilder Observatory | 1903 | Amherst, Massachusetts, US |
| Willard L. Eccles Observatory | 2009 | Frisco Peak, Utah, US |
| William Brydone Jack Observatory | 1851 | Fredericton, New Brunswick, Canada |
| Williams Observatory | 1990 | Boiling Springs, North Carolina, US |
| Winer Observatory | 1983 | Sonoita, Arizona, US |
| Winfree Observatory | 1900 | Lynchburg, Virginia, US |
| Wise Observatory | 1971 | Negev, Israel |
| Witte Observatory | 1984 | Mediapolis, Iowa, US |
| WIYN Observatory | 1994 | Kitt Peak, Arizona, US |
| Wyoming Infrared Observatory | 1975 | Laramie, Wyoming, US |
| Xiangfen Astronomical Observatory | 2100 BCE | Xiangfen County, Linfen, Shanxi Province, China |
| Xinglong Station (NAOC) | | Xinglong County, Chengde, Hebei province, China |
| Xinjiang Astronomical Observatory | 1968 | Urumqi, Xinjiang, China |
| XMM-Newton | 1999 | Highly eccentric Earth orbit |
| XRISM | 2023 | Earth orbit |
| XPoSat | 2024 | Earth orbit |
| Xujiahui Astronomical Observatory | 1872 | Shanghai, China |
| Arctic Space Weather Center | | Yakutsk, Russia |
| Yale Student Observatory | | New Haven, Connecticut, US |
| Yangbajing International Cosmic-Ray Observatory | | Yangbajing Valley, Tibet, China |
| Yantra Mandir | 1724 | New Delhi, Delhi, India |
| Yerevan Cosmic-Ray Station | | Yerevan, Armenia |
| Yerkes Observatory | 1897 | Williams Bay, Wisconsin, US |
| York University Observatory | 1969 | Toronto, Ontario, Canada |
| Yuba City Astronomical Observatory | 2010 | Yuba City, California, US |
| Yunnan Astronomical Observatory | 1957 | Kunming, Yunnan, China |
| Zimmerwald Observatory | 1956 | Zimmerwald, Switzerland |
| Zadko Observatory | 2009 | Gingin, Australia |