List of largest optical reflecting telescopes

This list of the largest optical reflecting telescopes with objective

Objective (optics)

In an optical instrument, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. Objectives can be single lenses or mirrors, or combinations of several optical elements. They are used in microscopes, telescopes,...

diameters greater than 1.8 meters is sorted by aperture: an optical diameter that reflects light-gathering power of the reflecting telescope

Reflecting telescope

A reflecting telescope is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century as an alternative to the refracting telescope which, at that time, was a design that suffered from...

's optical assembly and resolution.

The mirrors themselves can be larger than the aperture, and telescopes may use aperture synthesis

Aperture synthesis

Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection...

achieved by interferometry

Interferometry

Interferometry refers to a family of techniques in which electromagnetic waves are superimposed in order to extract information about the waves. An instrument used to interfere waves is called an interferometer. Interferometry is an important investigative technique in the fields of astronomy,...

. Telescopes designed to be used as optical astronomical interferometer

Astronomical interferometer

An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution by means of interferometry....

s such as the Keck I and II used together as the Keck Interferometer (up to 85 meters) can reach very high resolutions, although at a narrower range of observations. When the two mirrors are on one mount, the combined mirror spacing of the Large Binocular Telescope

Large Binocular Telescope

Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

(22.8 meters) allows fuller use of the aperture synthesis.

Largest does not always equate to being the best telescopes and overall light gathering power of the optical system can be poor measure of a telescope's performance.
Space-based telescopes

Space observatory

A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects...

, such as the Hubble Space Telescope

Hubble Space Telescope

The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

, take advantage of being above the Earths atmosphere

Atmosphere

An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

to reach higher resolution and greater light gathering through longer exposure time. Location in the northern or southern hemisphere of the Earth can also limit what part of the sky an be observed.

Table of reflecting telescopes

This list is ordered by optical aperture, which has historically been a useful gauge of limiting resolution, optical area, physical size, and cost. Multiple mirror telescopes that are on the same mount, may have a working beam combiner, and can form an image are ranked by an equivalent aperture to this reported by sources. HET-style or fixed telescopes are ranked by an equivalent aperture also.

Name	Image	Effective aperture Aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,... m	Aper. in Inch An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...	Mirror type Telescope A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...	Nationality / Sponsors	Site	Built
Large Binocular Telescope Large Binocular Telescope Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory... (LBT)		11.9 m (8.4 m×2)	330″×2	Multiple mirror, 2	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... , Italy Italy Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and... , Germany Germany Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...	Mount Graham Internationals Obs. Mount Graham International Observatory Mount Graham International Observatory is a division of Steward Observatory the research arm for the Department of Astronomy at The University of Arizona. It is located in southeast Arizona's Pinaleno Mountains near Mount Graham.... , Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...	2004
Gran Telescopio Canarias Gran Telescopio Canarias The Gran Telescopio Canarias , also known as GranTeCan or GTC, is a reflecting telescope undertaking commissioning observations at the Roque de los Muchachos Observatory on the island of La Palma, in the Canary Islands of Spain, as of July 2009.Construction of the telescope, sited on a volcanic... (GTC)		10.4 m	410″	Segmented Segmented mirror A segmented mirror is an array of smaller mirrors designed to act as segments of a single large curved mirror. The segments can be either spherical or asymmetric . They are used as objectives for large reflecting telescopes... , 36	Spain Spain Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula... (90%), Mexico Mexico The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of... , USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	ORM Roque de los Muchachos Observatory Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands... , Canary Islands Canary Islands The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...	2006/9
Keck 1		10 m	400″	Segmented, 36	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Mauna Kea Observatory Mauna Kea Observatory The Observatories at Mauna Kea, , are an independent collection of astronomical research facilities located on the summit of Mauna Kea on the Big Island of Hawai'i, USA. The facilities are located in a special land use zone known as the "Astronomy Precinct," which is located in the Mauna Kea... , Hawaii Hawaii Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...	1993
Keck 2		10 m	400″	Segmented, 36	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Mauna Kea Observatory Mauna Kea Observatory The Observatories at Mauna Kea, , are an independent collection of astronomical research facilities located on the summit of Mauna Kea on the Big Island of Hawai'i, USA. The facilities are located in a special land use zone known as the "Astronomy Precinct," which is located in the Mauna Kea... , Hawaii Hawaii Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...	1996
Southern African Large Telescope Southern African Large Telescope The Southern African Large Telescope is a 66m2 area optical telescope with a nominally 9.2 meter aperture but up to about 11.1m x ~9.8 m diameter aperture, and designed mainly for spectroscopy. It is located close to the town of Sutherland in the semi-desert region of the Karoo, South Africa... (SALT) (11 m × 9.8 m mirror)		9.2 m	362″	Segmented, 91	South Africa South Africa The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans... , USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... , UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... , Germany Germany Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate... , Poland Poland Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north... , New Zealand New Zealand New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...	South African Astronomical Observatory South African Astronomical Observatory South African Astronomical Observatory is the national center for optical and infrared astronomy in South Africa. It was established in 1972. The observatory is run by the National Research Foundation of South Africa. The facility's function is to conduct research in astronomy and astrophysics...	2005
Hobby-Eberly Telescope Hobby-Eberly Telescope The Hobby-Eberly Telescope is a 9.2-meter aperture telescope located at the McDonald Observatory. It combines a number of features that differentiate it from most telescope designs, resulting in greatly lowered construction costs... (HET) (11 m × 9.8 m mirror)		9.2 m	362″	Segmented, 91	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... , Germany Germany Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...	McDonald Observatory McDonald Observatory The McDonald Observatory is an astronomical observatory located near the unincorporated community of Fort Davis in Jeff Davis County, Texas, United States. The facility is located on Mount Fowlkes and Mount Locke in the Davis Mountains of West Texas... , Texas Texas Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...	1997
Subaru Subaru (telescope) Subaru Telescope is the 8.2 metre flagship telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades... (JNLT)		8.2 m	323″	Single	Japan Japan Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...	Mauna Kea Observatory Mauna Kea Observatory The Observatories at Mauna Kea, , are an independent collection of astronomical research facilities located on the summit of Mauna Kea on the Big Island of Hawai'i, USA. The facilities are located in a special land use zone known as the "Astronomy Precinct," which is located in the Mauna Kea... , Hawaii Hawaii Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...	1999
VLT Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... UT1 (Antu)		8.2 m	323″	Single	ESO Countries European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	Paranal Observatory Paranal Observatory Paranal Observatory is an astronomical observatory located on Cerro Paranal at 2,635 m altitude and operated by the European Southern Observatory. The Very Large Telescope is the largest telescope on Paranal, actually composed of four separate 8.2 m telescopes... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	1998
VLT Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... UT2 (Kueyen)		8.2 m	323″	Single	ESO Countries European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	Paranal Observatory Paranal Observatory Paranal Observatory is an astronomical observatory located on Cerro Paranal at 2,635 m altitude and operated by the European Southern Observatory. The Very Large Telescope is the largest telescope on Paranal, actually composed of four separate 8.2 m telescopes... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	1999
VLT Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... UT3 (Melipal)		8.2 m	323″	Single	ESO Countries European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	Paranal Observatory Paranal Observatory Paranal Observatory is an astronomical observatory located on Cerro Paranal at 2,635 m altitude and operated by the European Southern Observatory. The Very Large Telescope is the largest telescope on Paranal, actually composed of four separate 8.2 m telescopes... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	2000
VLT Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... UT4 (Yepun)		8.2 m	323″	Single	ESO Countries European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	Paranal Observatory Paranal Observatory Paranal Observatory is an astronomical observatory located on Cerro Paranal at 2,635 m altitude and operated by the European Southern Observatory. The Very Large Telescope is the largest telescope on Paranal, actually composed of four separate 8.2 m telescopes... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	2001
Gemini North (Gillett)		8.1 m	318″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... , UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... , Canada Canada Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far... , Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area... , Argentina Argentina Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires... , Brazil Brazil Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...	Mauna Kea Obs. Mauna Kea Observatory The Observatories at Mauna Kea, , are an independent collection of astronomical research facilities located on the summit of Mauna Kea on the Big Island of Hawai'i, USA. The facilities are located in a special land use zone known as the "Astronomy Precinct," which is located in the Mauna Kea... , Hawaii Hawaii Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...	1999
Gemini South		8.1 m	318″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... , UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... , Canada Canada Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far... , Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area... , Argentina Argentina Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires... , Brazil Brazil Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...	Cerro Pachón Cerro Pachón Cerro Pachón is a mountain located close to Chilean city of Vicuña and 10 km southeast of the Cerro Tololo Inter-American Observatory, at an altitude of 2,715 m over the sea level in the foothills of the Andes. The location is exceedingly dry, making it suitable for infrared observations.... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	2001
MMT MMT Observatory The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains... (1 x 6.5 M1)		6.5 m	256″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	F. L. Whipple Obs. Fred Lawrence Whipple Observatory The Fred Lawrence Whipple Observatory is an astronomical observatory owned and operated by the Smithsonian Astrophysical Observatory and is their largest field installation outside of their main site in Cambridge, MA... , Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...	2000
Magellan 1 (Walter Baade)		6.5 m	256″	Honeycomb	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Las Campanas Obs. Las Campanas Observatory Las Campanas Observatory is an astronomical observatory owned and operated by the Carnegie Institution for Science It was established in 1969 and remains the primary observing site of that institution. The headquarters is located in La Serena, Chile and the observatory is in the southern Atacama... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	2000
Magellan 2 (Landon Clay)		6.5 m	256″	Honeycomb	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Las Campanas Obs. Las Campanas Observatory Las Campanas Observatory is an astronomical observatory owned and operated by the Carnegie Institution for Science It was established in 1969 and remains the primary observing site of that institution. The headquarters is located in La Serena, Chile and the observatory is in the southern Atacama... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	2002
BTA-6 BTA-6 The BTA-6 is a 6 m aperture optical telescope at the Special Astrophysical Observatory located in the Zelenchuksky District on the north side of the Caucasus Mountains in southern Russia...		6 m	238″	Single	USSR, Russia Russia Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...	Zelenchukskaya Zelenchukskaya The Special Astrophysical Observatory , or SAO RAS for short, is an astronomical observatory, set up in 1966 in the USSR, now operated by the Russian Academy of Sciences. Based in the Bolshoi Zelenchuk Valley of the Greater Caucasus near the village of Nizhny Arkhyz, the observatory houses the... , Caucasus Caucasus The Caucasus, also Caucas or Caucasia , is a geopolitical region at the border of Europe and Asia, and situated between the Black and the Caspian sea...	1975
Large Zenith Telescope Large Zenith Telescope The Large Zenith Telescope is a 6.0 m diameter liquid mirror telescope located in the University of British Columbia's Malcolm Knapp Research Forest, about east of Vancouver... (LZT)		6 m	236″	Liquid Liquid mirror Liquid mirror telescopes are telescopes made with a reflective liquid. The most common liquid used is mercury, but other liquids will work as well . The container for the liquid is rotating so that the liquid assumes a paraboloidal shape. A paraboloidal shape is precisely the shape needed for the...	Canada Canada Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean... , France France The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France... , USA	Maple Ridge Maple Ridge, British Columbia Maple Ridge is a District Municipality in British Columbia, located in the northeastern section of Metro Vancouver. Maple Ridge has a population of approximately 68,949.-History:... , British Columbia British Columbia British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...	2003
Hale Telescope Hale telescope The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning... (200 inch)		5.08 m	200″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Palomar Observatory Palomar Observatory Palomar Observatory is a privately owned observatory located in San Diego County, California, southeast of Pasadena's Mount Wilson Observatory, in the Palomar Mountain Range. At approximately elevation, it is owned and operated by the California Institute of Technology... , California California California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...	1948
LAMOST LAMOST The Large Sky Area Multi-Object Fibre Spectroscopic Telescope is a meridian reflecting Schmidt telescope. Its optics comprise two roughly rectangular mirrors, each made up of a number of 1.1-metre hexagonal deformable segments, providing a focal plane 1.75 metres in diameter corresponding to a... (6.67 m × 6.05 m + 5.72 m × 4.40 m corrector; effective aperture 3.6–4.9 m)		4.9 m–3.6 m	193″	Segmented (37 + 24)	PRC (China)	Beijing Astronomical Obs., Xinglong Xinglong Station (NAOC) Xinglong Station is an observatory situated south of the main peak of the Yanshan mountains in Hebei province, China. Installed are seven telescopes: a Mark-III photoelectric astrolabe; a 60cm reflector; an 85cm reflector; a 60/90cm Schmidt telescope; an 1.26m infrared telescope; and a 2.16m... , China	2008
MMT MMT Observatory The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains... (6×1.8 m) original optics		4.7 m (6×1.8 m)	186″	Segmented, 6	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	F. L. Whipple Obs. Fred Lawrence Whipple Observatory The Fred Lawrence Whipple Observatory is an astronomical observatory owned and operated by the Smithsonian Astrophysical Observatory and is their largest field installation outside of their main site in Cambridge, MA... , Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...	1979–1998
William Herschel Telescope William Herschel Telescope The William Herschel Telescope is a optical/near-infrared reflecting telescope located at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, is part of the Isaac Newton Group of Telescopes...		4.2 m	165″	Single	UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages... , Netherlands Netherlands The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders... , Spain Spain Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...	ORM Roque de los Muchachos Observatory Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands... , Canary Islands Canary Islands The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...	1987
SOAR SOAR telescope The Southern Astrophysical Research Telescope is a modern 4.1-meter-aperture optical and near-infrared telescope located on Cerro Pachón, Chile at 2,738 meters elevation...		4.1 m	161″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district... , Brazil Brazil Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...	Cerro Pachón Cerro Pachón Cerro Pachón is a mountain located close to Chilean city of Vicuña and 10 km southeast of the Cerro Tololo Inter-American Observatory, at an altitude of 2,715 m over the sea level in the foothills of the Andes. The location is exceedingly dry, making it suitable for infrared observations.... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	2002
Victor M. Blanco Telescope Victor M. Blanco Telescope The Víctor M. Blanco Telescope, also known as the Blanco 4m, is a 4m telescope located at the Cerro Tololo Inter-American Observatory, Chile. Commissioned in 1974 and completed in 1976, this telescope is similar to the Mayall 4m telescope located on Kitt Peak. In 1995 it was dedicated and named in...		4 m	157″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Cerro Tololo Inter-American Obs. Cerro Tololo Inter-American Observatory The Cerro Tololo Inter-American Observatory is a complex of astronomical telescopes and instruments located at 30.169 S, 70.804 W, approximately 80 km to the East of La Serena, Chile at an altitude of 2200 metres. The complex is part of the National Optical Astronomy Observatory along with Kitt... , Chile Chile Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...	1976
Nicholas U. Mayall 4m Nicholas U. Mayall Telescope The Nicholas U. Mayall Telescope is a four meter reflector telescope located at the Kitt Peak National Observatory and named after Nicholas U. Mayall. It saw first light on February 27, 1973. Initial observers included: D. Crawford, Nicholas Mayall, and Arthur Hoag. It was dedicated on June 20,...		4 m	149.5″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Kitt Peak National Obs. Kitt Peak National Observatory The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson... ; Arizona Arizona Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...	1973
Anglo-Australian Telescope Anglo-Australian Telescope The Anglo-Australian Telescope is a 3.9 m equatorially mounted telescope operated by the Australian Astronomical Observatory and situated at the Siding Spring Observatory, Australia at an altitude of a little over 1100 m... (AAT)		3.89 m	154″	Single	Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area... , UK United Kingdom The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...	Australian Astronomical Obs.; Siding Spring, Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...	1975
3.67m AEOS Telescope 3.67 m Advanced Electro Optical System Telescope The 3.67 m Advanced Electro Optical System Telescope is a Department of Defense telescope at Haleakala Observatory.The 3.67-meter telescope, known as the Advanced Electro-Optical System , owned by the Department of Defense, is the United States' largest optical telescope designed for tracking... (AEOS)		3.67 m	145″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Air Force Maui Optical Station; Haleakala, Hawaii	1996
Telescopio Nazionale Galileo Telescopio Nazionale Galileo The Telescopio Nazionale Galileo, or TNG, is a 3.58m Italian telescope located on the island of San Miguel de La Palma , in the Canary Islands archipelago. It is one of the largest telescopes hosted by the Roque de los Muchachos Observatory, a very important observing site in the northern hemisphere... (TNG)		3.58 m	138″	Single	Italy Italy Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...	La Palma, Canary Islands	1997
New Technology Telescope New Technology Telescope The New Technology Telescope or NTT is an Alt-Az, 3.58-metre Richey-Chretien telescope part of the European Southern Observatory and began operations in 1989. It is located in Chile at the La Silla Observatory and was an early pioneer on the use of active optics... (NTT)		3.58 m	142″	Single	ESO countries European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...	European Southern Observatory European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries... ; Cerro La Silla, Chile	1989
Canada-France-Hawaii Telescope Canada-France-Hawaii Telescope The Canada–France–Hawaii Telescope is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters , and is one of the observatories that comprise the Mauna Kea Observatory... (CFHT)		3.58 m	141″	Single	Canada Canada Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean... , France France The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France... , USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Mauna Kea Observatories, USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	1979
ESO 3.6 m Telescope	\|	3.57 m	140″	Single	ESO countries European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...	European Southern Observatory European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries... ; Cerro La Silla, Chile	1977
MPI Max Planck Institute for Astronomy The Max-Planck-Institut für Astronomie is a research institute of the Max Planck Society. It is located in Heidelberg, Baden-Württemberg, Germany near the top of the Koenigstuhl, adjacent to the historic Landessternwarte Heidelberg-Königstuhl astronomical observatory.The institute was founded in... -CAHA Calar Alto Observatory The Calar Alto Observatory is an astronomical observatory owned and operated jointly by the Max-Planck-Institut für Astronomie in Heidelberg, Germany, and the Instituto... 3.5m		3.5 m	138″	Single	West Germany West Germany West Germany is the common English, but not official, name for the Federal Republic of Germany or FRG in the period between its creation in May 1949 to German reunification on 3 October 1990.... , Spain Spain Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...	Calar Alto Obs. Calar Alto Observatory The Calar Alto Observatory is an astronomical observatory owned and operated jointly by the Max-Planck-Institut für Astronomie in Heidelberg, Germany, and the Instituto... , Spain	1984
USAF Starfire 3.5m Starfire Optical Range Starfire Optical Range is a United States Air Force research laboratory on the Kirtland Air Force Base in Albuquerque, New Mexico...		3.5 m	138″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Starfire Optical Range Starfire Optical Range Starfire Optical Range is a United States Air Force research laboratory on the Kirtland Air Force Base in Albuquerque, New Mexico... ; New Mexico	1994
WIYN Telescope WIYN Observatory The WIYN Observatory is owned and operated by the WIYN Consortium. Its telescope, a 3.5-meter instrument, is the newest and second largest telescope on Kitt Peak in Arizona...		3.5 m	138″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Kitt Peak National Obs. Kitt Peak National Observatory The Kitt Peak National Observatory is a United States astronomical observatory located on 2,096 m Kitt Peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono O'odham Nation, southwest of Tucson... , USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	1994
Space Surveillance Telescope		3.5 m	138″	Single	DARPA	White Sands Missile Range White Sands Missile Range White Sands Missile Range is a rocket range of almost in parts of five counties in southern New Mexico. The largest military installation in the United States, WSMR includes the and the WSMR Otera Mesa bombing range...	2011
Astrophysical Research Consortium (ARC)		3.48 m	137″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Apache Point Obs. Apache Point Observatory The Apache Point Observatory is located in the Sacramento Mountains in Sunspot, New Mexico 18 miles south of Cloudcroft. The observatory consists of the Astrophysical Research Consortium's 3.5-meter telescope, the Sloan Digital Sky Survey 2.5-m telescope with a 20" photometric telescope,... ; Sacramento Peak, New Mexico New Mexico New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...	1994
Shane Telescope C. Donald Shane telescope The C. Donald Shane telescope is a reflecting telescope located at the Lick Observatory in California. It was named after astronomer C. Donald Shane in 1978, who led the effort to acquire the necessary funds from the California Legislature, and who then oversaw the telescope's construction...		3.05 m	120″	Single	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Lick Observatory Lick Observatory The Lick Observatory is an astronomical observatory, owned and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, USA... ; Mt. Hamilton, California	1959
NASA-LMT NASA Orbital Debris Observatory NASA Orbital Debris Observatory or NODO was an observatory that hosted NASA-LMT, a 3 meter diameter aperture liquid metal telescope and astronomical survey funded and operated by NASA from 1995 to 2002 in New Mexico, USA. It was a zenith or transit telescope pointed straight up, that used 20... (NODO) retired		3 m	118″	Liquid Liquid mirror Liquid mirror telescopes are telescopes made with a reflective liquid. The most common liquid used is mercury, but other liquids will work as well . The container for the liquid is rotating so that the liquid assumes a paraboloidal shape. A paraboloidal shape is precisely the shape needed for the...	USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	Sacramento Peak, New Mexico, USA United States The United States of America is a federal constitutional republic comprising fifty states and a federal district...	1995–2002
See List of large optical reflecting telescopes* for continuation of list*

This table does not include all the largest mirrors manufactured; the Steward Observatory

Steward Observatory

The University of Arizona's Steward Observatorys main office is located on the University's campus and is closely tied to the Department of Astronomy. Established in 1916 by its first director, Andrew Ellicott Douglass, and a $60,000 bequest made by Lavinia Steward in memory of her late husband...

Mirror Lab produced the 6.5-metre f/1.25 collimator used in the Large Optical Test and Integration Site

Large Optical Test and Integration Site

The Large Optical Test and Integration Site, or LOTIS, is a facility at the Lockheed Martin Space Systems Company in Sunnyvale, CA for testing large optical components under realistic conditions...

of Lockheed Martin

Lockheed Martin

Lockheed Martin is an American global aerospace, defense, security, and advanced technology company with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta in March 1995. It is headquartered in Bethesda, Maryland, in the Washington Metropolitan Area....

, used for vacuum optical testing of other telescopes.

Segmented

Segmented mirror

A segmented mirror is an array of smaller mirrors designed to act as segments of a single large curved mirror. The segments can be either spherical or asymmetric . They are used as objectives for large reflecting telescopes...

are also known as Mosaic mirrors. Single mirrors, also called monolithic and can be sub-categorized in types, such as solid or honeycomb.

Stem and leaf plot

The following is a modified stem and leaf plot

Stemplot

A stemplot , in statistics, is a device for presenting quantitative data in a graphical format, similar to a histogram, to assist in visualizing the shape of a distribution. They evolved from Arthur Bowley's work in the early 1900s, and are useful tools in exploratory data analysis...

of the above data. Each number on the right of the : is the effective aperture diameter (in metres) and is linked to the corresponding telescope's article.

Non-standard apertures, special, or retired telescopes have an asterisk.

11:

11.9

Large Binocular Telescope

10:

10.4

Gran Telescopio Canarias

The Gran Telescopio Canarias , also known as GranTeCan or GTC, is a reflecting telescope undertaking commissioning observations at the Roque de los Muchachos Observatory on the island of La Palma, in the Canary Islands of Spain, as of July 2009.Construction of the telescope, sited on a volcanic...

10,

*9.2

Southern African Large Telescope

The Southern African Large Telescope is a 66m2 area optical telescope with a nominally 9.2 meter aperture but up to about 11.1m x ~9.8 m diameter aperture, and designed mainly for spectroscopy. It is located close to the town of Sutherland in the semi-desert region of the Karoo, South Africa...

*9.2

Hobby-Eberly Telescope

The Hobby-Eberly Telescope is a 9.2-meter aperture telescope located at the McDonald Observatory. It combines a number of features that differentiate it from most telescope designs, resulting in greatly lowered construction costs...

8.2

Subaru (telescope)

Subaru Telescope is the 8.2 metre flagship telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades...

(8.2

Very Large Telescope

The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to...

8.2

Very Large Telescope

8.2

Very Large Telescope

8.2

Very Large Telescope

(8.1

Gemini Observatory

The Gemini Observatory is an astronomical observatory consisting of two telescopes at sites in Hawai‘i and Chile. Together, the twin Gemini telescopes provide almost complete coverage of both the northern and southern skies...

8.1

Gemini Observatory

)

6.5

MMT Observatory

The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains...

(6.5

Magellan telescopes

The Magellan Telescopes are a pair of 6.5 m diameter optical telescopes located at Las Campanas Observatory in Chile. The two telescopes are named after the astronomer Walter Baade and the philanthropist Landon T...

6.5

Magellan telescopes

BTA-6

The BTA-6 is a 6 m aperture optical telescope at the Special Astrophysical Observatory located in the Zelenchuksky District on the north side of the Caucasus Mountains in southern Russia...

Large Zenith Telescope

The Large Zenith Telescope is a 6.0 m diameter liquid mirror telescope located in the University of British Columbia's Malcolm Knapp Research Forest, about east of Vancouver...

5.08

Hale telescope

The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning...

*4.9

LAMOST

The Large Sky Area Multi-Object Fibre Spectroscopic Telescope is a meridian reflecting Schmidt telescope. Its optics comprise two roughly rectangular mirrors, each made up of a number of 1.1-metre hexagonal deformable segments, providing a focal plane 1.75 metres in diameter corresponding to a...

*4.7

MMT Observatory

4.2

William Herschel Telescope

The William Herschel Telescope is a optical/near-infrared reflecting telescope located at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, is part of the Isaac Newton Group of Telescopes...

4.1,

4.1

VISTA (telescope)

The VISTA is a reflecting telescope with a 4.1 metre mirror, located at the Paranal Observatory in Chile. It is operated by the European Southern Observatory and saw first light in December 2009...

Nicholas U. Mayall Telescope

The Nicholas U. Mayall Telescope is a four meter reflector telescope located at the Kitt Peak National Observatory and named after Nicholas U. Mayall. It saw first light on February 27, 1973. Initial observers included: D. Crawford, Nicholas Mayall, and Arthur Hoag. It was dedicated on June 20,...

Victor M. Blanco Telescope

The Víctor M. Blanco Telescope, also known as the Blanco 4m, is a 4m telescope located at the Cerro Tololo Inter-American Observatory, Chile. Commissioned in 1974 and completed in 1976, this telescope is similar to the Mayall 4m telescope located on Kitt Peak. In 1995 it was dedicated and named in...

3.89

Anglo-Australian Telescope

The Anglo-Australian Telescope is a 3.9 m equatorially mounted telescope operated by the Australian Astronomical Observatory and situated at the Siding Spring Observatory, Australia at an altitude of a little over 1100 m...

3.8

United Kingdom Infrared Telescope

UKIRT, the United Kingdom Infra-Red Telescope, is a 3.8 metre infrared reflecting telescope, the largest dedicated infrared telescope in the world. It is operated by the Joint Astronomy Centre in Hilo and located on Mauna Kea, Hawai'i as part of Mauna Kea Observatory...

3.67

3.67 m Advanced Electro Optical System Telescope

The 3.67 m Advanced Electro Optical System Telescope is a Department of Defense telescope at Haleakala Observatory.The 3.67-meter telescope, known as the Advanced Electro-Optical System , owned by the Department of Defense, is the United States' largest optical telescope designed for tracking...

3.58

Telescopio Nazionale Galileo

The Telescopio Nazionale Galileo, or TNG, is a 3.58m Italian telescope located on the island of San Miguel de La Palma , in the Canary Islands archipelago. It is one of the largest telescopes hosted by the Roque de los Muchachos Observatory, a very important observing site in the northern hemisphere...

3.58

New Technology Telescope

The New Technology Telescope or NTT is an Alt-Az, 3.58-metre Richey-Chretien telescope part of the European Southern Observatory and began operations in 1989. It is located in Chile at the La Silla Observatory and was an early pioneer on the use of active optics...

3.58

Canada-France-Hawaii Telescope

The Canada–France–Hawaii Telescope is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters , and is one of the observatories that comprise the Mauna Kea Observatory...

3.57,

3.5,

3.5

Starfire Optical Range

Starfire Optical Range is a United States Air Force research laboratory on the Kirtland Air Force Base in Albuquerque, New Mexico...

3.5

WIYN Observatory

The WIYN Observatory is owned and operated by the WIYN Consortium. Its telescope, a 3.5-meter instrument, is the newest and second largest telescope on Kitt Peak in Arizona...

*3.5

Herschel Space Observatory

The Herschel Space Observatory is a European Space Agency space observatory sensitive to the far infrared and submillimetre wavebands. It is the largest space telescope ever launched, carrying a single mirror of in diameter....

3.48,

3.05

C. Donald Shane telescope

The C. Donald Shane telescope is a reflecting telescope located at the Lick Observatory in California. It was named after astronomer C. Donald Shane in 1978, who led the effort to acquire the necessary funds from the California Legislature, and who then oversaw the telescope's construction...

*3,

Same table in inches

460:	469 Large Binocular Telescope Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...
410:	410 Gran Telescopio Canarias The Gran Telescopio Canarias , also known as GranTeCan or GTC, is a reflecting telescope undertaking commissioning observations at the Roque de los Muchachos Observatory on the island of La Palma, in the Canary Islands of Spain, as of July 2009.Construction of the telescope, sited on a volcanic...
400:	400,	400
360:	*362 Southern African Large Telescope The Southern African Large Telescope is a 66m2 area optical telescope with a nominally 9.2 meter aperture but up to about 11.1m x ~9.8 m diameter aperture, and designed mainly for spectroscopy. It is located close to the town of Sutherland in the semi-desert region of the Karoo, South Africa... ,	*362 Hobby-Eberly Telescope The Hobby-Eberly Telescope is a 9.2-meter aperture telescope located at the McDonald Observatory. It combines a number of features that differentiate it from most telescope designs, resulting in greatly lowered construction costs...
320:	323 Subaru (telescope) Subaru Telescope is the 8.2 metre flagship telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades... ,	(323 Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... ,	323 Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... ,	323 Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... ,	323 Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to... )
310:	(318 Gemini Observatory The Gemini Observatory is an astronomical observatory consisting of two telescopes at sites in Hawai‘i and Chile. Together, the twin Gemini telescopes provide almost complete coverage of both the northern and southern skies... ,	318 Gemini Observatory The Gemini Observatory is an astronomical observatory consisting of two telescopes at sites in Hawai‘i and Chile. Together, the twin Gemini telescopes provide almost complete coverage of both the northern and southern skies... )
250:	256 MMT Observatory The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains... ,	(256 Magellan telescopes The Magellan Telescopes are a pair of 6.5 m diameter optical telescopes located at Las Campanas Observatory in Chile. The two telescopes are named after the astronomer Walter Baade and the philanthropist Landon T... ,	256 Magellan telescopes The Magellan Telescopes are a pair of 6.5 m diameter optical telescopes located at Las Campanas Observatory in Chile. The two telescopes are named after the astronomer Walter Baade and the philanthropist Landon T... )
230:	238 BTA-6 The BTA-6 is a 6 m aperture optical telescope at the Special Astrophysical Observatory located in the Zelenchuksky District on the north side of the Caucasus Mountains in southern Russia... ,	*236 Large Zenith Telescope The Large Zenith Telescope is a 6.0 m diameter liquid mirror telescope located in the University of British Columbia's Malcolm Knapp Research Forest, about east of Vancouver...
200:	200 Hale telescope The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning...
190:	*193 LAMOST The Large Sky Area Multi-Object Fibre Spectroscopic Telescope is a meridian reflecting Schmidt telescope. Its optics comprise two roughly rectangular mirrors, each made up of a number of 1.1-metre hexagonal deformable segments, providing a focal plane 1.75 metres in diameter corresponding to a...
180:	*186 MMT Observatory The MMT Observatory is an astronomical observatory on the site of Fred Lawrence Whipple Observatory . The Whipple observatory complex is located on Mount Hopkins, Arizona, USA in the Santa Rita Mountains...
160:	165 William Herschel Telescope The William Herschel Telescope is a optical/near-infrared reflecting telescope located at the Observatorio del Roque de los Muchachos on the island of La Palma in the Canary Islands, Spain. The telescope, which is named after William Herschel, is part of the Isaac Newton Group of Telescopes... ,	161,	161 VISTA (telescope) The VISTA is a reflecting telescope with a 4.1 metre mirror, located at the Paranal Observatory in Chile. It is operated by the European Southern Observatory and saw first light in December 2009...
150:	158 Nicholas U. Mayall Telescope The Nicholas U. Mayall Telescope is a four meter reflector telescope located at the Kitt Peak National Observatory and named after Nicholas U. Mayall. It saw first light on February 27, 1973. Initial observers included: D. Crawford, Nicholas Mayall, and Arthur Hoag. It was dedicated on June 20,... ,	157 Victor M. Blanco Telescope The Víctor M. Blanco Telescope, also known as the Blanco 4m, is a 4m telescope located at the Cerro Tololo Inter-American Observatory, Chile. Commissioned in 1974 and completed in 1976, this telescope is similar to the Mayall 4m telescope located on Kitt Peak. In 1995 it was dedicated and named in... ,	154 Anglo-Australian Telescope The Anglo-Australian Telescope is a 3.9 m equatorially mounted telescope operated by the Australian Astronomical Observatory and situated at the Siding Spring Observatory, Australia at an altitude of a little over 1100 m... ,	150 United Kingdom Infrared Telescope UKIRT, the United Kingdom Infra-Red Telescope, is a 3.8 metre infrared reflecting telescope, the largest dedicated infrared telescope in the world. It is operated by the Joint Astronomy Centre in Hilo and located on Mauna Kea, Hawai'i as part of Mauna Kea Observatory...
140:	145 3.67 m Advanced Electro Optical System Telescope The 3.67 m Advanced Electro Optical System Telescope is a Department of Defense telescope at Haleakala Observatory.The 3.67-meter telescope, known as the Advanced Electro-Optical System , owned by the Department of Defense, is the United States' largest optical telescope designed for tracking... ,	138 Telescopio Nazionale Galileo The Telescopio Nazionale Galileo, or TNG, is a 3.58m Italian telescope located on the island of San Miguel de La Palma , in the Canary Islands archipelago. It is one of the largest telescopes hosted by the Roque de los Muchachos Observatory, a very important observing site in the northern hemisphere... ,	142 New Technology Telescope The New Technology Telescope or NTT is an Alt-Az, 3.58-metre Richey-Chretien telescope part of the European Southern Observatory and began operations in 1989. It is located in Chile at the La Silla Observatory and was an early pioneer on the use of active optics... ,	141 Canada-France-Hawaii Telescope The Canada–France–Hawaii Telescope is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters , and is one of the observatories that comprise the Mauna Kea Observatory... ,	140
130:	138,	138 Starfire Optical Range Starfire Optical Range is a United States Air Force research laboratory on the Kirtland Air Force Base in Albuquerque, New Mexico... ,	138 WIYN Observatory The WIYN Observatory is owned and operated by the WIYN Consortium. Its telescope, a 3.5-meter instrument, is the newest and second largest telescope on Kitt Peak in Arizona... ,	*138 Herschel Space Observatory The Herschel Space Observatory is a European Space Agency space observatory sensitive to the far infrared and submillimetre wavebands. It is the largest space telescope ever launched, carrying a single mirror of in diameter.... ,	137
120:	120 C. Donald Shane telescope The C. Donald Shane telescope is a reflecting telescope located at the Lick Observatory in California. It was named after astronomer C. Donald Shane in 1978, who led the effort to acquire the necessary funds from the California Legislature, and who then oversaw the telescope's construction...
110:	*118,	*118

Top telescope 2010

The very largest telescopes are multi-telescope interferometers, and may have longer baselines.
However, these astronomical interferometers are less flexible in use, and many interferometers cannot form images or see faint objects despite their high peak angular resolution.

The largest telescope during the first decade of the 21st century could be either the Gran Telescopio Canarias

Gran Telescopio Canarias

(one 10.4 diameter mirror), the Large Binocular Telescope

Large Binocular Telescope

(two 8.4 diameter mirrors on a binocular mount), or the Very Large Telescope

Very Large Telescope

(with four 8.2 m telescopes, four 1.8 m auxiliary telescopes, and a 2.61 m Survey Telescope

VLT Survey Telescope

The VLT Survey Telescope is the latest telescope to be added to ESO’s Paranal Observatory in the Atacama Desert of northern Chile. It is housed in an enclosure immediately adjacent to the four Very Large Telescope Unit Telescopes on the summit of Cerro Paranal. The VST is a wide-field survey...

). However, as these were still coming online in the period, the two 10 meter Keck Telescopes

Keck telescopes

The W. M. Keck Observatory is a two-telescope astronomical observatory at an elevation of near the summit of Mauna Kea in Hawai'i. The primary mirrors of each of the two telescopes are in diameter, making them the second largest optical telescopes in the world, slightly behind the Gran Telescopio...

(with 85 m aperture synthesis) were possibly the largest in full scientific operation.

Note other wavelengths of telescopes can be much larger physically, such as the 305 m aperture Arecibo radio telescope

Arecibo Observatory

The Arecibo Observatory is a radio telescope near the city of Arecibo in Puerto Rico. It is operated by SRI International under cooperative agreement with the National Science Foundation...

, but since radio wavelengths are also larger, this does not necessarily translate into brighter or higher resolution images.

Name	Out	In	aperture (m)	equiv. Area (m)	Area (m²)	Mirrors	Note	Altitude
Gran Telescopio Canarias Gran Telescopio Canarias The Gran Telescopio Canarias , also known as GranTeCan or GTC, is a reflecting telescope undertaking commissioning observations at the Roque de los Muchachos Observatory on the island of La Palma, in the Canary Islands of Spain, as of July 2009.Construction of the telescope, sited on a volcanic... (GTC)			10.4	10.4	74 m²	36 x 1.9 m hexagonal segments for M1	Commissioned 2009; Largest single mirror	2267 m
Southern African Large Telescope Southern African Large Telescope The Southern African Large Telescope is a 66m2 area optical telescope with a nominally 9.2 meter aperture but up to about 11.1m x ~9.8 m diameter aperture, and designed mainly for spectroscopy. It is located close to the town of Sutherland in the semi-desert region of the Karoo, South Africa... (SALT)			11 (max.)	9.2	66–45 m²	92 x 1 m hexagon; 11 x 9.8 m mirror	HET Hobby-Eberly Telescope The Hobby-Eberly Telescope is a 9.2-meter aperture telescope located at the McDonald Observatory. It combines a number of features that differentiate it from most telescope designs, resulting in greatly lowered construction costs... twin but larger optically. Spherical M1 w/ fixed mirror; spectroscopy (see here)	1783 m
Keck 1 & 2			10 m each	10 m	76 m² each	36 x 1.8 m hexagons M1 mirrors each	largest twin telescopes 152 m² total optical area	4145 m
VLT 1,2,3, & 4 Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to...			8.2 m each	8.2	53 m² each	1 x 8.2 m M1 each	Largest quadruplet telescope 210 m² total optical area	2635 m
Large Binocular Telescope Large Binocular Telescope Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory... (LBT)			8.4 m each	11.7	111 m² (both sides)	2 x 8.4 m M1 mirrors; 1 mount	Largest Binocular; largest non-segmented mirrors; 22.8 m aperture planned	3221 m

Largest telescopes with interferometer mode, and two image-forming interferometer arrays.

Name	Longest baseline (m)	Mirrors	Area	Equiv.	Note
VLTI	200	4 x 8.2 m (VLT 1,2,3, & 4)	210 m²	16	Behind schedule
Keck Interferometer	85	2 x 10 m (Keck 1 & 2)	152 m²
LBT (LBTI)	22.8*	2 x 8.4	110 m²	11.9	One telescope mount*; Fizeau & Amplitude Interferometry
CHARA array CHARA array The CHARA Array is an optical astronomical interferometer operated by The Center for High Angular Resolution Astronomy of the Georgia State University . CHARA is the World's highest angular resolution telescope at near-infrared wavelengths...	330	6 x 1 m	2.45 m²
NPOI Navy Prototype Optical Interferometer The Navy Prototype Optical Interferometer , is an astronomical interferometer operated by the United States Naval Observatory Flagstaff Station, in collaboration with the Naval Research Laboratory and The Lowell Observatory...	437	6 siderostats (visible)	Sparse Aperture		Optically resolved Mizar (star) Mizar (star) The Mizar–Alcor stellar sextuple system consists of the quadruple system Mizar and the binary system Alcor.- Description :Mizar is a quadruple system of two binary stars in the constellation Ursa Major and is the second star from the end of the Big Dipper's handle. Its apparent magnitude is 2.23...

*Baseline does not reduce with viewing angle

Top telescope 2000

Name	Out	In	aperture (m)	Area (m²)	Mirrors	Note	Altitude
Keck 1 & 2			10 m each	76 m² each	36 x 1.8 m hexagons M1 mirrors each	largest twin telescopes, largest aperture mirrors, 152 m² total optical area	4145 m
Hobby-Eberly Telescope Hobby-Eberly Telescope The Hobby-Eberly Telescope is a 9.2-meter aperture telescope located at the McDonald Observatory. It combines a number of features that differentiate it from most telescope designs, resulting in greatly lowered construction costs... (HET)			9.2 (max.)	66–45 m²	92 x 1 m hexagon; 11 x 9.8 m mirror	Spherical M1 w/ fixed mirror; spectroscopy	2030 m
Subaru Telescope Subaru (telescope) Subaru Telescope is the 8.2 metre flagship telescope of the National Astronomical Observatory of Japan, located at the Mauna Kea Observatory on Hawaii. It is named after the open star cluster known in English as the Pleiades...			8.2	53 m²	1 x 8.3 m M1	Largest single piece mirror (tied with the 4 VLT)	4145 m
VLT 1,2,3, & 4 Very Large Telescope The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. The VLT consists of four individual telescopes, each with a primary mirror 8.2m across, which are generally used separately but can be used together to...			8.2 m each	53 m² each	1 x 8.2 m M1	Largest quadruplet telescope; largest single piece mirrors (tied with Subaru)	2635 m

Chronologically

Years Largest	Name	Out	In	aperture (m)	Area (m²)	M1 Mirror	Note	Altitude
2009–Present	Gran Telescopio Canarias Gran Telescopio Canarias The Gran Telescopio Canarias , also known as GranTeCan or GTC, is a reflecting telescope undertaking commissioning observations at the Roque de los Muchachos Observatory on the island of La Palma, in the Canary Islands of Spain, as of July 2009.Construction of the telescope, sited on a volcanic...			10.4 m	74 m²	36 x 1.9 m hexagons M1 mirror	Segmented mirror	2267 m
1993–2009	Keck 1			10 m	76 m²	36 x 1.8 m hexagons M1 mirror	Segmented mirror, M1 f/1.75	4145 m
1976–1993	BTA-6 BTA-6 The BTA-6 is a 6 m aperture optical telescope at the Special Astrophysical Observatory located in the Zelenchuksky District on the north side of the Caucasus Mountains in southern Russia...			6 m	26 m²	605 cm f/4 M1 mirror	Mirror replaced twice	2070 m
1948–1976	Hale (200 inch) Hale telescope The Hale Telescope is a , 3.3 reflecting telescope at the Palomar Observatory in California, named after astronomer George Ellery Hale. With funding from the Rockefeller Foundation, he orchestrated the planning, design, and construction of the observatory, but did not live to see its commissioning...			5.1 m	m²	508 cm f/3.3 M1 mirror	Art deco Art Deco Art deco , or deco, is an eclectic artistic and design style that began in Paris in the 1920s and flourished internationally throughout the 1930s, into the World War II era. The style influenced all areas of design, including architecture and interior design, industrial design, fashion and... dome	1713 m
1917–1948	Hooker (100 inch)			2.54 m	m²		also used for 1st optical interferometer	1742 m

For earlier top telescopes see List of largest optical telescopes historically

Plans

Below are selected telescopes that are still in the conceptual/proposed stage or still under construction.

Under construction or planned construction

European Extremely Large Telescope 42 m (140 ft)
Thirty Meter Telescope
Thirty meter telescope
The Thirty Metre Telescope is a proposed ground-based large segmented mirror reflecting telescope to be built on Mauna Kea in Hawaii. The telescope is designed for observations from the near-ultraviolet to the mid-infrared . An adaptive optics system would correct for image blur caused by the...

30 m
Giant Magellan Telescope
Giant Magellan Telescope
The Giant Magellan Telescope is a ground-based extremely large telescope planned for completion in 2018. It will consist of seven diameter primary segments, with the resolving power of a primary mirror and collecting area equivalent to one...

7×8.4 m mirrors = 24.5 m aperture (21.4 m equivalent area)
Large Synoptic Survey Telescope
Large Synoptic Survey Telescope
The Large Synoptic Survey Telescope is a planned wide-field "survey" reflecting telescope that will photograph the available sky every three nights. The LSST is currently in its design and development phase and will achieve engineering first light four years after construction starts...

8.4 m (2015 first light planned)
James Webb Space Telescope
James Webb Space Telescope
The James Webb Space Telescope , previously known as Next Generation Space Telescope , is a planned next-generation space telescope, optimized for observations in the infrared. The main technical features are a large and very cold 6.5 meter diameter mirror, an observing position far from Earth,...

6.5 m (2015 launch planned)
Discovery Channel Telescope
Discovery Channel Telescope
The Discovery Channel Telescope is a 4.3-meter aperture telescope being built by Lowell Observatory in Flagstaff, Arizona and will be the fifth largest telescope in the continental United States once completed in 2012. The DCT is currently under construction at a dark sky site on the Coconino...

4.3 m (M1 mirror installed)
Automated Planet Finder
Automated Planet Finder
The Automated Planet Finder Telescope is a fully automated 2.4-meter optical telescope under construction at Lick Observatory designed to search for extrasolar planets in the range of five to twenty times the mass of the Earth. The instrument will examine 25 stars per night. Over a decade, the...

2.4 m (almost complete)
Pan-STARRS
Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System is a planned array of astronomical cameras and telescopes and computing facility that will survey the sky on a continual basis, including accurate astrometry and photometry of detected objects...

4 x 1.8 m (1 online)
Magdalena Ridge Observatory Telescope Array 10 x 1.4 m
Thai National Telescope Project 2.4 m
Advanced Technology Solar Telescope
Advanced Technology Solar Telescope
The Advanced Technology Solar Telescope is a large domed solar telescope facility that is planned to be built by the National Solar Observatory atop the Haleakala volcano on the Pacific island of Maui. The site was selected for its clear daytime atmospheric seeing conditions, which will enable...

4 m (see also list of solar telescopes)
International Liquid Mirror Telescope 4 m

Proposed or planned

ALPACA telescope, 8 m liquid mirror
Advanced Technology Large-Aperture Space Telescope
Advanced Technology Large-Aperture Space Telescope
The Advanced Technology Large-Aperture Space Telescope is an 8 to 16.8-meter UV-optical-NIR space telescope proposed by Space Telescope Science Institute, the science operations center for the Hubble Space Telescope...

(ATLAST), 8-15m space telescope

Formerly proposed or planned

Overwhelmingly Large Telescope
Overwhelmingly Large Telescope
The Overwhelmingly Large Telescope is a conceptual design by the European Southern Observatory organization for an extremely large telescope, which was intended to have a single aperture of 100 meters in diameter...

60-100 m study concluded
Euro 50 50 m study concluded
Large Atacama Telescope
Hubble Origins Probe
Hubble Origins Probe
The Hubble Origins Probe is an orbital telescope proposed by an international team led by Johns Hopkins University astronomers. The proposed telescope would make use of designs from the Hubble Space Telescope , and instruments that were intended for the planned 4th HST servicing mission, as well...

study concluded

External links

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Table of reflecting telescopes

Stem and leaf plot

Top telescope 2010

Top telescope 2000

Chronologically

Plans

See also

Further reading

External links