List of highest astronomical observatories
Introduction View showing several of the world's highest observatory sites in Chile, looking north across the Llano de Chajnantor and ALMA site, with the peaks of Cerro Toco (right center) and Cerro Chajnantor (right) rising above.This is a '''list of the highest astronomical observatories''' in the world, considering only ground-based observatories and ordered by elevation above mean sea level. The main list includes only permanent observatories with facilities constructed at a fixed location, followed by a supplementary list for temporary observatories such as transportable telescopes or instrument packages. For large observatories with numerous telescopes at a single location, only a single entry is included listing the main elevation of the observatory or of the highest operational instrument if that information is available.
History of high altitude astronomical observatories Prior to the late 19th century, almost all astronomical observatories throughout history were located at modest elevations, often close to cities and educational institutions for the simple reason of convenience. As air pollution from industrialization and light pollution from artificial lighting increased during the Industrial Revolution, astronomers sought observatory sites in remote locations with clear and dark skies, naturally drawing them towards the mountains. The first permanent mountaintop astronomical observatory was the Lick Observatory constructed from 1876 to 1887, at the modest elevation of  atop Mount Hamilton in California. The first high altitude observatory was constructed atop the  Pic du Midi de Bigorre in the French Pyrenees starting in 1878, with its first telescope and dome installed in 1904.Astronomical observations were also made from Mont Blanc in the late 1800s.A few other high altitude observatories (such as the Lowell Observatory in Arizona and Sphinx Observatory in Switzerland) were constructed through the first half of the 20th century. However, the two most important and prominent of the early 20th century observatories, Mount Wilson Observatory and Palomar Observatory, were both located on mid-elevation mountaintops of about  in southern California. The stunning successes and discoveries made there using the world's largest telescopes, the 100-inch Hooker Telescope and 200-inch Hale Telescope, spurred the move to ever higher sites for the new generation of observatories and telescopes after World War II, along with a worldwide search for locations which had the best astronomical seeing.Since the mid-20th century, an increasing number of high altitude observatory sites have been developed at locations around the world, including numerous sites in Arizona, Hawaii, Chile, and the Canary Islands. The initial wave of high-altitude sites were mostly in the  range, but astronomers soon sought even higher sites above . Among the largest, best developed, and most renowned of these high altitude sites is the Mauna Kea Observatory located near the summit of a  volcano in Hawaii, which has grown to include over a dozen major telescopes during the four decades since it was founded. In the first decade of the 21st century, there has been a new wave of observatory construction at very high altitudes above , with such observatories constructed in India, Mexico, and most notably the Atacama Desert in northern Chile, now the site of several of the world's highest observatories. The scientific benefits of these sites outweigh the numerous logistical and physiological challenges which must be overcome during the construction and operation of observatories in remote mountain locations, even in desert, polar, and tropical island sites which magnify the challenges but confer additional observational advantages.Sites at high altitude are ideal for optical astronomy and provide optimal seeing, being above a significant portion of the Earth's atmosphere with its associated weather, turbulence, and diminished clarity. In particular, sites on mountaintops within about  of the ocean often have excellent observing conditions above a stable inversion layer throughout much of the year. High altitude sites are also above most of atmosphere's water vapor, making them ideal for infrared astronomy and submillimeter astronomy as those wavelengths are strongly absorbed by water vapor. On the other hand, high altitude does not offer as significant an advantage for radio astronomy at longer wavelengths, so relatively few radio telescopes are located at such sites. At the far end of the spectrum, for the extremely short wavelengths of x-ray and gamma ray astronomy, along with high-energy cosmic rays, high altitude observations once again offers significant advantages, enough that many experiments at these wavelengths have been conducted by balloon-borne or even by space telescopes, although a number of high-altitude ground-based sites have also been used. These include the Chacaltaya Astrophysical Observatory in Bolivia, which at  was the world's highest permanent astronomical observatory from the time of its construction during the 1940s until surpassed in 2009 by the new University of Tokyo Atacama Observatory, an optical-infrared telescope on a remote  mountaintop in Chile.
Highest permanent observatories Permanent observatories above 3,000 m: Observatory Name Elevation Observatory Site Location Coordinates Established Type of Observatory Major Instruments University of Tokyo Atacama Observatory (TAO)  Cerro Chajnantor Atacama Desert, Chile  2009 Optical, infrared Chacaltaya Astrophysical Observatory  Chacaltaya Andes, Bolivia  1946 Cosmic ray, gamma ray James Ax Observatory  Cerro Toco Atacama Desert, Chile  2011 Microwave POLARBEAR Atacama Cosmology Telescope  Cerro Toco Atacama Desert, Chile  2007 Microwave Llano de Chajnantor Observatory  Llano de Chajnantor Atacama Desert, Chile  1999 Millimeter wave, submillimeter ALMA, APEX, QUIET Shiquanhe Observatory (NAOC Ali Observatory)   Shiquanhe, Ngari Plateau Tibet Autonomous Region, China  2011 Optical Large Latin American Millimeter Array (LLAMA)  Alto de Chorillos Salta, Argentina  Under Construction Submillimeter LLAMA,  QUBIC Llano de Chajnantor Observatory  Pampa La Bola Atacama Desert, Chile  2002 Submillimeter ASTE, NANTEN2 Large Millimeter Telescope Alfonso Serrano  Sierra Negra Puebla, Mexico  2006 Microwave Indian Astronomical Observatory  Mount Saraswati Hanle, Ladakh, India  2001 Infrared, gamma ray, Optical Himalayan Chandra Telescope, HAGAR Meyer–Womble Observatory  Mount Blue Sky Colorado, United States  1996 Optical, Infrared Yangbajing International Cosmic Ray Observatory  Yangbajain Tibet Autonomous Region, China  1990 Cosmic ray Mauna Kea Observatory  Mauna Kea Hawaii, United States  1967 Optical, infrared, submillimeter Keck, UKIRT, Gemini North, Subaru, JCMT, CSO, SMA, CFHT High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory    Sierra Negra Puebla, Mexico  2013 Gamma ray Barcroft Observatory  White Mountain Peak California, United States  1976 Infrared, millimeter wave Very Long Baseline Array (VLBA), Mauna Kea Site  Mauna Kea Hawaii, United States  1986 Radio telescope Llano del Hato National Astronomical Observatory  Llano del Hato Andes, Venezuela  1970s Optical telescope 1-m Askania Schmidt camera, a 65-cm Zeiss refractor, a 1-m Zeiss reflector and a 50-cm Askania double astrograph Iranian National Observatory  Mount Gargash Isfahan, Iran  2010s Optical telescope  Under Construction Sphinx Observatory  Jungfraujoch Bernese Alps, Switzerland  1937 Optical telescope Mauna Loa Observatory  Mauna Loa Hawaii, United States  1957 Optical, millimeter wave Mauna Loa Solar Observatory, AMiBA Observatorio Astronómico de Moquegua  Cambrune Moquegua, Peru  2022 Optical 1m optical telescope in Astroshell dome Magdalena Ridge Observatory  South Baldy New Mexico, United States  1999 Optical, infrared Mount Graham International Observatory  Mount Graham Arizona, United States  1993 Optical, submillimeter LBT, HHST, VATT Gornergrat Observatory  Gornergrat Pennine Alps, Switzerland  1967 Infrared, submillimeter Gornergrat Infrared Telescope, KOSMA Peak Terskol Observatory  Peak Terskol North Caucasus, Russia  1980 Optical 2-m Ritchey-Chretien-Coude Zeiss since 1995, 60-cm Zeiss reflector European Extremely Large Telescope  Cerro Armazones Atacama Desert, Chile   Not completed Optical, near infrared  Haleakala Observatory  Haleakala Hawaii, United States  1964 Optical, millimeter wave Pan-STARRS, LCOGT Faulkes Telescope North, AEOS Notre Dame University–Louaize Observatory  Mount Lebanon Peak Al-Znanir, Lebanon  Not completed Optical telescope  Under Construction
Highest temporary observatories Temporary observatories above 3,000 m: Observatory Name Elevation Observatory Site Location Coordinates Established Type of Observatory Major Instruments Receiver Lab Telescope  Cerro Sairecabur Atacama Desert, Chile  2002 Submillimeter, 1–2 THz PLATO (PLATeau Observatory)  Dome A East Antarctic Ice Sheet, Antarctica  2008 Optical, submillimeter Concordia Station  Dome C East Antarctic Ice Sheet, Antarctica  2005 Optical, infrared, submillimeter
Other important high altitude observatories This is a selected list of the most important and notable high altitude observatories between 1700 and 3000 m; it is not intended to list all of the numerous observatories worldwide in this elevation range: Observatory Name Elevation Observatory Site Location Coordinates Established Type of Observatory Major InstrumentsSierra Nevada Observatory  Sierra Nevada Granada, Spain  1981 Optical Pic du Midi Observatory  Pic du Midi de Bigorre Pyrenees, France  1878 Optical, solar Bernard Lyot Telescope Amundsen-Scott South Pole Station /Martin A. Pomerantz Observatory  South Pole East Antarctic Ice Sheet, Antarctica  1994 Microwave, millimeter, neutrino, submillimeter SPT, AMANDA, IceCube, QUaD Cerro Armazones Observatory  Cerro Armazones Atacama Desert, Chile  1995 Optical telescope Hexapod-Telescope National Astronomical Observatory (Mexico)  Sierra de San Pedro Mártir Baja California, Mexico  1967 Optical telescope Apache Point Observatory  Sacramento Peak New Mexico, United States  1984 Optical, solar SDSS, Dunn Solar Telescope Cerro Pachón  Cerro Pachón Atacama Desert, Chile  2000 Optical, infrared Gemini South, SOAR National Astronomical Observatory (Colombia)  Metropolitan Area of Bogotá Bogotá, Colombia  1803 Optical telescope Paranal Observatory  Cerro Paranal Atacama Desert, Chile  1999 Optical, infrared VLT, VISTA Fred Lawrence Whipple Observatory  Mount Hopkins Arizona, United States  1966 Optical, gamma ray MMT, VERITAS Roque de los Muchachos Observatory  Roque de los Muchachos La Palma, Canary Islands  1979 Optical, infrared, solar, gamma ray MAGIC, GTC, WHT, TNG, NOT, INT Teide Observatory  Pico del Teide Tenerife, Canary Islands  1964 Optical, solar, microwave VTT, BRT, OGS, VSA La Silla Observatory  La Silla Atacama Desert, Chile  1969 Optical telescope NTT, ESO Las Campanas Observatory  Cerro Las Campanas Atacama Desert, Chile  1971 Optical telescope Magellan Telescopes, GMT Lowell Observatory  Flagstaff Arizona, United States  1894 Optical telescope Cerro Tololo Inter-American Observatory  Cerro Tololo Atacama Desert, Chile  1967 Optical telescope Victor M. Blanco Telescope Calar Alto Observatory  Calar Alto Almería, Spain  1975 Optical telescope Very Large Array  Plains of San Agustin New Mexico, United States  1975 Radio telescope Kitt Peak National Observatory  Kitt Peak Arizona, United States  1960 Optical, solar, radio telescope Mayall, WIYN, McMath-Pierce, VLBA Special Astrophysical Observatoryof the Russian Academy of Science  Mount Pastukhov Caucasus Mountains, Russia  1966 Optical telescope BTA-6 Yunnan Astronomical Observatory  rural Kunming, Yunnan, China rural Kunming, Yunnan, China  1972 Optical telescope, Radio, Solar, Infrared Lijiang 2.4m telescope, Fuxian Lake 1m solar tower, ynao 1m telescope, 10m radio telescope. Mount Wilson Observatory  Mount Wilson California, United States  1908 Optical, solar Hale Telescope (60"), Hooker Telescope (100") Palomar Observatory  Palomar Mountain California, United States  1936 Optical telescope Hale Telescope (200"), Samuel Oschin telescope
See also * List of telescope types* Lists of telescopes* List of astronomical observatories* Observational astronomy
References Note: References for most elevations can be found in the linked main article for each observatory. ; Citations; Bibliography* * *