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

NameEstablishedLocation
Abastumani Astrophysical Observatory1932Abastumani, Georgia
Abu Reyhan-e Birooni Observatory1976Shiraz University, Shiraz, Iran
Adirondack Public ObservatoryTupper Lake, New York, US
Aditya-L12023Sun-Earth L1
Adolphson Observatory2013Monmouth, Illinois, US
Airdrie Public Observatory1896Airdrie, Scotland, UK
Aker Observatory1995Safford, Arizona, US
Aldershot Observatory1906Aldershot, Hampshire, England, UK
Algonquin Radio Observatory1959Algonquin Provincial Park, Ontario, Canada
Allegheny Observatory1859Pittsburgh, Pennsylvania, US
Ametlla de Mar Observatory1992l'Ametlla de Mar, Catalonia, Spain
AMiBA2006Mauna Loa, Hawaii, US
Anderson Mesa Station1959Flagstaff, Arizona, US
Andrushivka Astronomical Observatory2001Andrushivka, Zhytomyr Oblast, Ukraine
Angell Hall Observatory1927Ann Arbor, Michigan, US
Ankara University Observatory1963Gölbaşı, Ankara, Turkey
Antarctic Muon and Neutrino Detector Array2002Antarctica
Antarctic Submillimeter Telescope and Remote Observatory1994–2005Antarctica
ANTARES2008In the Mediterranean Sea near Toulon, France
2005Overgaard, Arizona, US
Apache Point Observatory1985Sunspot, New Mexico, US
Apatity Cosmic-Ray StationApatity, Russia
Apollo Observatory1969Dayton, Ohio, US
Arcetri ObservatoryArcetri, Florence, Italy
Arecibo Observatory1963Arecibo, Puerto Rico, US
Argentine Institute of Radio Astronomy1966Berazategui Partido, Buenos Aires Province, Argentina
Armagh Observatory1790Armagh, UK
Aryabhatta Research Institute of Observational Sciences1954Nainital, Uttarakhand, India
Ashton Observatory1983Baxter, Iowa, US
Asiago Astrophysical Observatory1942Asiago, Italy
Assheton Observatory1860Lancashire, UK
ASTRON
1949Dwingeloo, Netherlands
Astron '1983–1989Highly eccentric Earth orbit
Astronomical Observatory Aurora2011Hechingen, Germany
Astronomical Observatory of Lisbon1867Lisbon, Portugal
Astronomy Centre1982Todmorden, England
Astronomy Tower of the Sorbonne1885–1909 Paris, France
Astrophysical Institute Potsdam1992Potsdam, Germany
Atacama Pathfinder Experiment (APEX)2003Llano de Chajnantor Observatory, Chile
Australia Telescope Compact Array1988Narrabri, Australia
Australian Astronomical Observatory1971Coonabarabran, Australia
Badlands Observatory2000Quinn, South Dakota, US
Baikal Deep Underwater Neutrino Telescope1993Baikal Lake, Russia
Bangladesh Astronomical Observatory2015Dhaka, Bangladesh
Baker Observatory1980Marshfield, Missouri, US
Baksan Neutrino Observatory1977Prielbrusye, Baksan Valley, Russia
Ball State University ObservatoryMuncie, Indiana, US
Barnard Observatory '1859Oxford, Mississippi, US
Bareket Observatory1990Maccabim, Israel
Barnett Observatory1960Chesterfield, England, UK
Bayfordbury Observatory1969Hertfordshire, England, UK
Behlen Observatory1972Mead, Nebraska, US
Beijing Astronomical Observatory1958Beijing, China
Beijing Ancient Observatory1442Beijing, China
Belgrade Observatory1887Belgrade, Serbia
Belogradchik Observatory1961Belogradchik, Bulgaria
Benito Loyola Observatory2024Virginia Beach, Virginia, US
Benmore Peak Observatory1996Mackenzie Basin, South Island, New Zealand
BeppoSAX '1996–2003Low Earth orbit
Bergisch Gladbach Observatory1995Bergisch Gladbach, Germany
Berlin Observatory1711Berlin, Germany
Besançon Observatory1882Besançon, France
Beverly-Begg Observatory1922Dunedin, South Island, New Zealand
Bidston Observatory1849Bidston, England, UK
Big Bear Lake Solar Observatory1969Big Bear City, California, US
Bisdee Tier Optical Astronomy Observatory2010Bisdee Tier, Spring Hill, Tasmania, Australia
Black Moshannon Observatory '1972Pennsylvania, US
Blackett Observatory1930sWiltshire, England, UK
Blue Mesa Observatory '1967New Mexico, US
1987Boambee, [New South Wales], Australia
Bohyunsan Optical Astronomy Observatory 1996Youngchun, South Korea
BOOTES1985Spain
Bordeaux Observatory1878Floirac, France
Bosscha Observatory1923Lembang, West Java, Indonesia
Boswell Observatory '1883Crete, Nebraska, US
Bowman Observatory1940Greenwich, Connecticut, US
Boyden Observatory1889Bloemfontein, South Africa
Bradstreet Observatory1996St. Davids, Pennsylvania, US
Brackett Observatory1908Pomona College, Claremont, California, US
Bradley Observatory1950Decatur, Georgia, US
Braeside Observatory '1976Flagstaff, Arizona, US
Brera Observatory1764Milan, Italy
Bridgewater State University Observatory2012Bridgewater, Massachusetts, US
Brooks ObservatoryToledo, Ohio, US
Brooks Astronomical Observatory1964Mount Pleasant, Michigan, US
Brorfelde Observatory1953Holbæk, Denmark
Bucharest Astronomical Observatory1910Bucharest, Romania
Bucknell ObservatoryLewisburg, Pennsylvania, US
Burrell Memorial Observatory1940Berea, Ohio, US
Byurakan Observatory1946Mount Aragats, Armenia
Cagigal Observatory1888Caracas, Venezuela
Cagliari Observatory1899Cagliari, Sardinia, Italy
Calais Observatory '1857Calais, Maine, US
Calar Alto Observatory1975Almería, Spain
Caltech Submillimeter Observatory '1986Mauna Kea, Hawaii, US
Cambridge Observatory1823Cambridge, UK
Camille Flammarion Observatory1883Juvisy-sur-Orge, France
Campbelltown Rotary Observatory2000Campbelltown, NSW, Australia
Campo Imperatore Near-Earth Object Survey2001Campo Imperatore, Italy
Canopus Hill ObservatoryHobart, Tasmania, Australia
Capilla Peak Observatory1947Albuquerque, New Mexico, US
Capodimonte Observatory1812Naples, Italy
Carruthers Geocorona Observatory2025Earth–Sun L1 point
Carter Observatory1937Wellington, New Zealand
Catania Astrophysical ObservatoryCatania, Italy
Cawthron Atkinson Observatory1883Nelson, New Zealand
Celestial ObservatoryRussellville, Arkansas, US
Centennial Observatory2004Twin Falls, Idaho, US
Center for Astrophysics Harvard & Smithsonian1973Cambridge, Massachusetts, US
Cerro Armazones Observatory1995Atacama Desert, Chile
Cerro Tololo Inter-American Observatory1962Atacama Desert, Chile
Cerro Pachón Observatory2000Atacama Desert, Chile
Chabot Space & Science Center1883Oakland, California, US
Chamberlin Observatory1890Denver, Colorado, US
Changchun Astronomical ObservatoryChangchun, Jilin Province, China
Chandra X-ray Observatory1999Highly eccentric Earth orbit
Chianti Polifunctional Observatory2013San Donato in Poggio, Florence, Italy
Chico Community Observatory2001Chico, California, US
Chilbolton Observatory1967Chilbolton, UK
Cima Ekar Observing Station1966Asiago, Italy
Cincinnati Observatory1843Cincinnati, Ohio, US
City Observatory, Edinburgh1818Edinburgh, Scotland, UK
Clarke Observatory1897 / 1923Dunkirk, New York / Alliance, Ohio, US
Class of 1951 Observatory1997Poughkeepsie, New York, US
Cloudcroft Observatory '1962New Mexico, US
Coats Observatory1883Paisley, Scotland, UK
Coit ObservatoryBoston, Massachusetts, US
Collins Observatory2003Corning, New York, US
Collm ObservatoryLeipzig, Germany
Colombo University Observatory1920sColombo, Sri Lanka
Compton Gamma-Ray Observatory '1991–2000Low Earth orbit
ÇOMÜ Ulupınar Observatory2002Çanakkale, Turkey
Concordia College ObservatoryMoorhead, Minnesota, US
Consell Observatory1987Mallorca, Spain
Copenhagen University Observatory1861Copenhagen, Denmark
Cordell–Lorenz ObservatorySewanee, Tennessee, US
COROT2006Polar orbit
Cosmic Background Imager '1999Llano de Chajnantor Observatory, Chile
Côte d'Azur Observatory1988France
Crane ObservatoryTopeka, Kansas, US
Crawford Observatory1880Cork, Ireland
Creighton University Observatory '1886–1955Omaha, Nebraska, US
Crimean Astrophysical Observatory1945Nauchnyi, Crimea
Črni Vrh Observatory1975Idrija, Slovenia
Cupillari ObservatoryLa Plume, Pennsylvania, US
Custer Observatory1927Southold, New York, US
& Observatory2023Nicosia, Cyprus
Daniel S. Schanck Observatory '1865Rutgers University, New Brunswick, New Jersey, US
Daniel Scholl Observatory '1886–1966Lancaster, Pennsylvania, US
Daocheng Solar Radio Telescope2022Daocheng County, Garze Tibetan Autonomous Prefecture, Sichuan Province, China.
Dark Sky Observatory1981Phillips Gap, Wilkes County, North Carolina, US
Dark Matter Particle Explorer (DAMPE)2015500 km LEO
Darling's Observatory '1917Duluth, Minnesota, US
Dearborn Observatory1889Evanston, Illinois, US
Detroit Observatory1854Ann Arbor, Michigan, US
David Dunlap Observatory1935Richmond Hill, Ontario, Canada
Dome CAntarctica
Dominion Observatory1905Ottawa, Ontario, Canada
Dominion Astrophysical Observatory1918Saanich, British Columbia, Canada
Dominion Radio Astrophysical Observatory1960Kaleden, British Columbia, Canada
Dunsink Observatory1785Dublin, Ireland
Durham University Observatory1839Durham, UK
Dyer Observatory1953Brentwood, Tennessee, US
Effelsberg 100-m Radio Telescope1972Bonn, Germany
Ege University Observatory1965Kemalpaşa, İzmir, Turkey
Einstein Probe2024Low Earth orbit
Einstein Observatory '1978Low Earth orbit
Elginfield Observatory1969Middlesex Centre, Ontario, Canada
2004Sterling Hill Mining Museum, Ogdensburg, New Jersey, US
Embry-Riddle Observatory2005Daytona Beach, Florida, US
Entoto Observatory Space Science Research Center2012Mount Entoto, Ethiopia
Eskdalemuir Observatory1908Dumfries and Galloway, Scotland, UK
Euclid Telescope2023Earth–Sun Lagrangian point
European Southern Observatory
  • 1969
  • 1989
  • 2005
  • 1998
  • 1999
  • 2026
    		• Atacama Desert, Chile
    Fabra Observatory1906Barcelona, Spain
    Fan Mountain Observatory1966Albemarle County, Virginia, US
    Five-hundred-meter Aperture Spherical Radio Telescope2013Duyun, Pingtang County, Guizhou Province, China
    Félix Aguilar Observatory1965San Juan, Argentina
    Fernbank ObservatoryAtlanta, Georgia, US
    Fermi Gamma-ray Space Telescope2008Low Earth orbit
    Fick Observatory1966Boone, Iowa, US
    Five College Radio Astronomy Observatory '1976–2011New Salem, Massachusetts, US
    Flarestar ObservatorySan Gwann, Malta
    Foggy Bottom Observatory1951Hamilton, New York, US
    Foothill ObservatoryLos Altos Hills, California, US
    Ford Observatory1998Ithaca, New York, US
    Fox ObservatorySunrise, Florida, US
    Fox Park Public Observatory1999Potterville, Michigan, US
    Francis Marion University Observatory1982Florence, South Carolina, US
    Fred Lawrence Whipple Observatory1968Mount Hopkins, Arizona, US
    Fremont Peak Observatory1986San Juan Bautista, California, US
    Frosty Drew Observatory1980sCharlestown, Rhode Island, US
    Fuertes Observatory1917Ithaca, New York, US
    Galaxy Evolution Explorer 2003Caltech, Jet Propulsion Laboratory, California, US
    Gaocheng Astronomical Observatory1276Dengfeng, Henan, China
    Gauribidanur Radio Observatory1976Gauribidanur, Karnataka, India
    Gemini Observatory1999Southern Operations Center: La Serena, Chile; Northern Operations Center: Hilo, Hawaii, US
    George Observatory1989Brazos Bend State Park, near Houston, Texas, US
    Giant Meterwave Radio Telescope (GMRT)1995Pune, Maharashtra, India
    Gifford Observatory1912Wellington, New Zealand
    Girawali Observatory2006Pune, Maharashtra, India
    Glen D. Riley Observatory1973Naperville, Illinois, US
    Godlee Observatory1902Manchester, England, UK
    Goodsell Observatory1887Northfield, Minnesota, US
    Goethe Link Observatory1939Brooklyn, Indiana, US
    Goldendale Observatory1973Goldendale, Washington, US
    Gornergrat (HFSJG) '1967–2005Gornergrat, Switzerland
    Granat '1989–1999Highly eccentric Earth orbit
    Gran Telescopio Canarias2006Canary Islands, Spain
    Grant O. Gale Observatory1984Grinnell, Iowa, US
    Green Bank Telescope2000Green Bank, West Virginia, US
    Green Point Observatory1961Sutherland, New South Wales, Australia
    Grenfell Observatory2012Corner Brook, Newfoundland and Labrador, Canada
    Griffith Observatory1935Los Angeles, California, US
    Guillermo Haro Observatory1972Cananea, Sonora, Mexico
    Gyarah SidiAgra, Uttar Pradesh, India
    HALCA '1997–2005Elliptical Earth-centered orbit
    Haleakala ObservatoryMaui, Hawaii, US
    Halley Observatory1987Heesch, Netherlands
    Hamburg Observatory1803Hamburg, Germany
    Hat Creek Radio Observatory1950sShasta County, California, US
    Hard Labor Creek ObservatoryAtlanta, Georgia, US
    Space Hard X-Ray Modulation Telescope (HXMT)2017550 km LEO
    Hartung–Boothroyd Observatory1974Ithaca, New York, US
    Hartebeesthoek Radio Astronomy Observatory1961Gauteng, South Africa
    Hartwell House1831Hartwell, Buckinghamshire, UK
    Harvard College Observatory1839Cambridge, Massachusetts, US
    Haute-Provence Observatory1937Alpes-de-Haute-Provence, France
    Haystack Observatory1964Westford, Massachusetts, US
    Hector J Robinson Observatory1964Lincoln Park, Michigan, US
    Helium and Lead Observatory2012Sudbury, Ontario, Canada
    Helmos Observatory2007Mount Helmos, Greece
    Helsinki University Observatory1834Helsinki/Kirkkonummi, Finland
    Herrett Observatory2004Twin Falls, Idaho, US
    Herschel Space Observatory2009Earth–Sun L2 point
    Hidden Valley Observatory1960sRapid City, South Dakota, US
    Hida Observatory, Kyoto University1968Takayama, Gifu, Japan
    Heyden Observatory, Georgetown University1844Washington, D.C., US
    High Altitude Water Cherenkov Observatory2015Sierra Negra, Puebla, Mexico
    High Energy Stereoscopic System2002Khomas Region, Namibia
    Highland Road Park Observatory1997Baton Rouge, Louisiana, US
    Hinode2006Low Earth orbit
    Hirsch Observatory1942Troy, New York, US
    Hobbs Observatory1974Fall Creek, Wisconsin, US
    Hoher List Observatory1954Daun, Germany
    Holcomb Observatory and Planetarium1954Indianapolis, Indiana, US
    Hong Kong Observatory1883Tsim Sha Tsui, Kowloon, Hong Kong
    Hoober Observatory1993Rotherham, UK
    Hopkins Observatory1838Williamstown, Massachusetts, US
    Howell ObservatoryStarkville, Mississippi, US
    Hradec Králové Observatory1961Hradec Králové, Czech Republic
    Huairou Solar Observing StationBeijing, China
    Hubble Space Telescope1990Low Earth orbit
    Huggins Observatory defunct1856London, England, UK
    Hume Cronyn Memorial Observatory1940London, Ontario, Canada
    Hyde Memorial Observatory1977Lincoln, Nebraska, US
    IceCube Neutrino Observatory2010Amundsen–Scott South Pole Station, Antarctica
    Indian Astronomical Observatory2001Hanle, Ladakh, India
    2008Humble, Texas, US
    Instituto de Astrofísica de Canarias1975Canary Islands, Spain
    INTEGRAL2002Highly eccentric Earth orbit
    Infrared Astronomical Satellite (IRAS) 'January–November 1983Earth orbit
    Infrared Space Observatory (ISO) '1995–1998Earth orbit
    Innsbruck ObservatoryInnsbruck, Austria
    IRAM 30m telescope1984Pico Veleta, Spain
    IRAM Plateau de Bure Interferometer1988Gap, Hautes-Alpes, France
    Iranian National Observatory2017Mount Gargash, Iran
    Isaac Newton Group of Telescopes1979La Palma, Spain
    Isaac Roberts' Observatory '1890Crowborough, UK
    Iso-Heikkilä Observatory '1935 Turku, Finland
    Constantinople Observatory of Taqi ad-Din1577Constantinople, Turkey
    Istanbul University Observatory1936Istanbul, Turkey
    Istituto Ricerche Solari Locarno, IRSOL1960Locarno, Switzerland
    IXPE2021Earth orbit
    Jack C. Davis Observatory2002Carson City, Nevada, US
    Astronomical Observatory of the Jagiellonian University1792Kraków, Poland
    James Clerk Maxwell Telescope1987Mauna Kea, Hawaii, US
    James Gregory Telescope1962St. Andrews, UK
    James Webb Space Telescope2021Earth–Sun Lagrangian point
    James Wylie Shepherd Observatory2009Montevallo, Alabama, US
    Jakarta Observatory1968Jakarta, Indonesia
    Jantar Mantar1727Jaipur, Rajasthan, India
    Jena Observatory1962Jena, Germany
    Jewett Observatory1953Pullman, Washington, US
    Jodrell Bank Observatory1945Cheshire, England, UK
    JAC Johor Astronomy2014Johor, Malaysia
    Jones Observatory1936Chattanooga, Tennessee, US
    Jordan Hall of Science2006Notre Dame, Indiana, US
    Judson B. Coit ObservatoryBoston, Massachusetts, US
    KAIRA2011Kilpisjarvi, Finland
    Khajeh Nasiredin Observatory~1980Tabriz University, Tabriz, Iran
    Kamioka Observatory1983Hida, Gifu, Japan
    Kanzelhoehe Solar Observatory1943Villach, Austria
    Karl Schwarzschild Observatory1960Jena, Germany
    Keck Observatory1993Mauna Kea, Hawaii, US
    Keeble Observatory1963Ashland, Virginia, US
    Keele 1962Keele University, England, UK
    Kennon Observatory1939Oxford, Mississippi, US
    Kepler Space Observatory2009Earth-trailing heliocentric orbit
    Kevola Observatory1963Kevola, Finland
    Kielder Observatory2008Kielder Forest, Northumberland, England, UK
    King's Observatory '1769Greater London, England, UK
    Kirkwood Observatory1901Bloomington, Indiana, US
    Kiso Observatory1974Mount Ontake, Japan
    Kitami Observatory1987Hokkaidō, Japan
    Kitt Peak National Observatory1958Tucson, Arizona, US
    Kleť Observatory1957České Budějovice, Czech Republic
    Kodaikanal Solar Observatory1899Palani, Tamil Nadu, India
    Konkoly Observatory1871Budapest, Hungary
    Kopernik Observatory & Science Center1974Vestal, New York, US
    KOSMA observatory1985–2010Gornergrat, Switzerland
    Kottamia Astronomical Observatory1964Cairo Governorate, Egypt
    Kryoneri Observatory1972Mount Kyllini, Greece
    Kuffner observatory1884Vienna, Austria
    Kuiper Airborne Observatory 197414 km in the stratosphere
    Kwasan Observatory, Kyoto University1929Kyoto, Japan
    Kvistaberg Observatory1948Bro, Sweden
    Kyung Hee Observatory1992Seoul, South Korea
    Laboratoire d'Astrophysique de Grenoble2001Grenoble, France
    Observatorio de La Cañada 2002Ávila, Spain
    Ladd Observatory1891Providence, Rhode Island, US
    Lake Afton Public Observatory1979Wichita, Kansas, US
    Lamont–Hussey Observatory '1928Bloemfontein, South Africa
    Landessternwarte Heidelberg-Königstuhl1898Königstuhl, Heidelberg, Germany
    Landolt Astronomical Observatory1939Baton Rouge, Louisiana, US
    La Plata Astronomical Observatory1883La Plata, Argentina
    La Silla Observatory1969Atacama Desert, Chile
    Large Binocular Telescope Observatory2005Mount Graham, Arizona, US
    Large High Altitude Air Shower Observatory (LHAASO)2019Daocheng County, Sichuan, China
    Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST)2009Xinglong Station, Hebei, China
    Large Millimeter Telescope2011Sierra Negra, Puebla, Mexico
    Las Brisas Observatory1979Colorado, US
    Las Campanas ObservatoryLa Serena, Chile
    Langkawi National Observatory2012Langkawi Island, Malaysia
    Las Cumbres Observatory Global Telescope2005Global network
    Laws Observatory1880Columbia, Missouri, US
    Leander McCormick Observatory1885Mount Jefferson, Charlottesville, Virginia, US
    Lee Observatory1873American University of Beirut, Beirut, Lebanon
    Leiden Observatory1633Leiden University, Leiden, Netherlands
    Leipzig ObservatoryLeipzig, Germany
    Leoncito Astronomical Complex1986Calingasta, San Juan, Argentina
    Levenhagen ObservatorySeattle, Washington, US
    Lick Observatory1881Mount Hamilton, San Jose, California, US
    LightBuckets 2007Rodeo, New Mexico, US
    [LIGO|][Hanford Site|] & [Livingston, Louisiana|], US
    Lindheimer Astrophysical Research Center '1966–1995Evanston, Illinois, US
    Llano de Chajnantor Observatory2005Atacama Desert, Chile
    Llano del Hato National Astronomical Observatory1975Mérida, Venezuela
    Lockyer Technology Centre2010Sidmouth, Devon, England, UK
    Long Wavelength Array2010Socorro, New Mexico, US
    Longa Vista Observatory2010Itatiba, SP, Brazil
    Lowell Observatory
  • 1959
    		• Flagstaff, Arizona, US
    Lucknow Observatory1832–1848Lucknow, India
    Lulin Observatory1999Mount Lulin, Taiwan
    Lund Observatory1749Lund, Sweden
    Luoxue Mountain Cosmic Rays Research Center1953Luoxue Mountain, Yunnan Province, China
    Lyon Observatory1878Saint-Genis-Laval, France
    Macalester College ObservatorySaint Paul, Minnesota, US
    Macfarlane Observatory defunct1757Glasgow, Scotland, UK
    Magdalena Ridge Observatory
  • Magdalena Ridge Observatory Single Telescope
  • Magdalena Ridge Observatory Interferometer
    		• 2006
  • 2008
  • Under construction
    		• Socorro County, New Mexico, US
    Mallorca Observatory1991Mallorca, Spain
    Malakoff Tower1845Recife, Brazil
    Manastash Ridge Observatory1972Ellensburg, Washington, US
    Manuel Foster Observatory '1903Santiago, Chile
    Maragheh Observatory1259Maragheh, Iran
    Margaret M. Jacoby Observatory1978Warwick, Rhode Island, US
    Maria Mitchell Observatory1908Nantucket, Massachusetts, US
    Marina Towers Observatory '1989Maritime Quarter, Swansea, Wales, UK
    Markree Observatory '1837County Sligo, Ireland
    Marseille ObservatoryMarseille, France
    Martz ObservatoryChautauqua County, New York, US
    Mauna Kea Observatory1967Mauna Kea, Hawaii, US
    Mauna Loa Solar ObservatoryHawaii, US
    Maynard F. Jordan Observatory1901Orono, Maine, US
    McDonald ObservatoryDavis Mountains, Texas, US
    McKim Observatory1884Greencastle, Indiana, US
    McMath–Hulbert Solar Observatory1930Lake Angelus, Michigan, US
    MDM ObservatoryKitt Peak, Arizona, US
    Mead Observatory2001Columbus, Georgia, US
    Medicina Radio Observatory1965Medicina, Bologna, Italy
    Mees ObservatoryRochester, New York, US
    Mehalso ObservatoryErie, Pennsylvania, US
    Melbourne Observatory1862Melbourne, Victoria, Australia
    Melton Memorial Observatory1928Columbia, South Carolina, US
    Mendenhall Observatory2002Stillwater, Oklahoma, US
    Menke Observatory1994Davenport, Iowa, US
    Metsähovi Observatory1966Kirkkonummi, Finland
    Meudon Observatory1876Meudon, France
    Meyer–Womble Observatory1996Mount Evans, Colorado, US
    Michigan State University Observatory1969East Lansing, Michigan, US
    Observatoire Midi-Pyrénées
  • Pyrenees, France
  • Toulouse, France
    • Milagro1999Los Alamos, New Mexico, US
    Miller Observatory1976Maiden, North Carolina, US
    Mills Observatory1938Dundee, Scotland, UK
    2018Sebastian, Florida, US
    MMT Observatory1979Mount Hopkins, Arizona, US
    Modine-Benstead Observatory1963Union Grove, Wisconsin, US
    Modra Observatory1988Modra, Slovakia
    Mohr Observatory '1765–1780Jakarta, Indonesia
    Moletai Astronomical Observatory1969Moletai, Lithuania
    Molonglo Observatory Synthesis Telescope 1960Bungendore, New South Wales, Australia
    Mont Mégantic Observatory1978Mont Mégantic, Québec, Canada
    Monterey Institute for Research in Astronomy1972
    		Chews Ridge, California &
    Monterey, California, US
    Montevideo National ObservatoryMontevideo, Uruguay,
    Moore Observatory1978Oldham County, Kentucky, US
    Morgan–Monroe Observatory1966Morgan–Monroe State Forest, Indiana, US
    Morris Observatory1973North Manchester, Indiana, US
    Morrison ObservatoryFayette, Missouri, US
    Moscow Cosmic-Ray StationTroitsk, Russia
    Mount Stony Brook Observatory1968Stony Brook, New York, US
    Mounds ObservatoryTulsa, Oklahoma, US
    Mount Abu InfraRed Observatory1995Mount Abu, Rajasthan, India
    Mount Burnett Observatory1972Mount Burnett, Victoria, Australia
    Mount Cuba Astronomical ObservatoryGreenville, Delaware, US
    Mount Graham International Observatory1993Mount Graham, Arizona, US
    Mount John University Observatory1965Lake Tekapo, South Island, New Zealand
    Mount Laguna Observatory1968San Diego, California, US
    Mount Lemmon ObservatoryTucson, Arizona, US
    Mount Pleasant Radio ObservatoryTasmania, Australia
    Mount Stromlo Observatory1911Canberra, Australia
    Mount Suhora Observatory1987Gorce Mountains, Poland
    Mount Wilson Observatory1904Mount Wilson, Los Angeles County, California, US
    Mountain Skies Observatory1997Lyman, Wyoming, US
    Mullard Radio Astronomy Observatory1957Cambridge, England, UK
    Murchison Radio-astronomy Observatory2012Murchison, Western Australia, Australia
    Mykolaiv Astronomical Observatory1821Mykolaiv, Mykolaiv Oblast, Ukraine
    Nachi-Katsuura ObservatoryNachikatsuura, Wakayama, Japan
    Nançay Radio Telescope1965Nançay, France
    Nanjing Astronomical Instruments Research Centre1958Nanjing, Jiangsu Province, China
    National Astronomical Observatory (Colombia)1803Bogotá, Colombia
    National Astronomical Observatory of Japan1988Headquarters: Mitaka, Tokyo, Japan
    National Astronomical Observatory (Mexico)1967Sierra San Pedro Mártir, Baja California, Mexico
    National Observatory (Brazil)1827Rio de Janeiro, Brazil
    National Observatory of Athens1842Athens, Greece
    National Optical Astronomy Observatory
    • 1820
    • 1972
    		Observatory, Cape Town, South Africa
  • Sutherland, Northern Cape, South Africa
    • Southern Astrophysical Research Telescope (SOAR)2004Cerro Pachón, Chile
    South Pole Telescope2007Antarctica
    Spanish National Observatory1790Madrid, Spain
    Special Astrophysical Observatory of the Russian Academy of Sciences1966Zelenchukskaya, near Arkhyz, Caucasus Mountains, Russia
    Sperry Observatory1967Cranford, New Jersey, US
    SPHEREx2025Sun-synchronous Earth orbit
    Spitzer Space Telescope2003Heliocentric orbit
    Springfield Observatory1968Springfield, Massachusetts, US
    Sproul Observatory1911Swarthmore, Pennsylvania, US
    Stardome Observatory1967Auckland, North Island, New Zealand
    Starkenburg Observatory1970Heppenheim, Germany
    Štefánik's Observatory1928Prague, Czech Republic
    Stellafane Observatory1920Springfield, Vermont, US
    2019Kanab, Utah, US
    1901Hiram, Ohio, US
    Steward Observatory
  • 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 Observatory1881Rio de Janeiro, Brazil
    Vainu Bappu Observatory1968Kavalur, Tamil Nadu, India
    Astronomical observatory of Aosta Valley2003Nus, Aosta Valley, Italy
    Van Vleck Observatory1914Middletown, Connecticut, US
    Vanderbilt University ObservatoryNashville, Tennessee, US
    Vartiovuori Observatory '1819–1834Turku, Finland
    Vassar College Observatory '1865Poughkeepsie, New York, US
    Vatican Observatory
  • 1993
    		• Headquarters: Castel Gandolfo, Italy