List of largest optical telescopes historically

Telescope performance has progressed in many ways since their invention in 1608. The following tables list those steps in performance.

Table of largest optical telescopes historically by overall aperture

The following is a list of largest single mount

Telescope mount

A telescope mount is a mechanical structure which supports a telescope. Telescope mounts are designed to support the mass of the telescope and allow for accurate pointing of the instrument...

optical telescope

Optical telescope

An optical telescope is a telescope which is used to gather and focus light mainly from the visible part of the electromagnetic spectrum for directly viewing a magnified image for making a photograph, or collecting data through electronic image sensors....

s sorted by total 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,...

diameter (aperture) including 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...

and multi-mirror configurations. It is a historical list with the instruments listed in chronological succession by objective size. Diameter of the primary optics alone can be poor measure of a telescope's historical or scientific significance; for example, William Parsons, 3rd Earl of Rosse

William Parsons, 3rd Earl of Rosse

William Parsons, 3rd Earl of Rosse, Knight of the Order of St Patrick was an Irish astronomer who had several telescopes built. His 72-inch telescope "Leviathan", built 1845, was the world's largest telescope until the early 20th century.-Life:He was born in Yorkshire, England, in the city of...

's 72-inch (1.8 m) reflecting telescope

Leviathan of Parsonstown

Leviathan of Parsonstown is the unofficial name of the Rosse six foot telescope. This is a historic reflecting telescope of 72 in aperture, which was the largest telescope in the world from 1845 until the construction of the 100 in Hooker Telescope in 1917...

did not perform as well (i.e. gather as much light) as the smaller silvered glass mirror telescopes that succeeded it because of the poor performance of its speculum metal

Speculum metal

Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors...

mirror.

Name	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...	Type	Built by	Location	Year
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″	Reflector 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... - 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(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	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... , 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...	2009
Keck 1	10 m	400″	Reflector 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... - 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	USA	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	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	238″	Reflector 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...	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...	1976
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″	Reflector 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...	USA	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	1948
Hooker 100-Inch Telescope Mount Wilson Observatory The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles...	2.54 m	100″	Reflector 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...	USA	Mt. Wilson Observatory; California	1917
Leviathan of Parsonstown Leviathan of Parsonstown Leviathan of Parsonstown is the unofficial name of the Rosse six foot telescope. This is a historic reflecting telescope of 72 in aperture, which was the largest telescope in the world from 1845 until the construction of the 100 in Hooker Telescope in 1917...	1.83 m	72″	Reflector 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... - metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors...	William Parsons William Parsons, 3rd Earl of Rosse William Parsons, 3rd Earl of Rosse, Knight of the Order of St Patrick was an Irish astronomer who had several telescopes built. His 72-inch telescope "Leviathan", built 1845, was the world's largest telescope until the early 20th century.-Life:He was born in Yorkshire, England, in the city of...	Birr Castle Birr Castle Birr Castle is a large castle in the town of Birr in County Offaly, Ireland. It is the home of the seventh Earl of Rosse, and as such the residential areas of the castle are not open to the public, though the grounds and gardens of the demesne are publicly accessible.-Ireland's Historic Science... ; Ireland Ireland Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...	1845
Herschel 40-foot 40-foot telescope William Herschel's 40-foot telescope, also known as the Great Forty-Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a 120 cm diameter primary mirror with a 12 m long focal length . It was the largest telescope in... (126 cm d.)	1.26 m	49.5″	Reflector 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... - metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors...	William Herschel William Herschel Sir Frederick William Herschel, KH, FRS, German: Friedrich Wilhelm Herschel was a German-born British astronomer, technical expert, and composer. Born in Hanover, Wilhelm first followed his father into the Military Band of Hanover, but emigrated to Britain at age 19...	Observatory House Observatory House Observatory House was an observatory in Slough, England. It was built, run and used by the astronomer William Herschel, and his sister Caroline. The famous '40-foot telescope' - at that time the largest in the world - was housed there in the late 18th century and early 19th century.The main house... ; England	1789–1815
Rev John Michell's Gregorian reflector	75 cm	29.5″	Reflector 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... - Gregorian Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	John Michell John Michell John Michell was an English natural philosopher and geologist whose work spanned a wide range of subjects from astronomy to geology, optics, and gravitation. He was both a theorist and an experimenter....	Yorkshire Yorkshire Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform... , Great Britain	1780–1789
Father Noel's Gregorian reflector	60 cm	23.5″	Reflector 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... - Gregorian Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	Father Noel	Paris, France	1761
James Short's Gregorian reflector	50 cm	19.5"	Reflector 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... - Gregorian Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	James Short	Scotland Scotland Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...	1750
James Short's Gregorian reflector	38 cm	14″	Reflector 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... - Gregorian Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	James Short	Scotland Scotland Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...	1734
Christiaan Huygens 210 foot refractor	22 cm	8.5"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - Aerial telescope Aerial telescope An aerial telescope is a type of very-long-focal-length refracting telescope built in the second half of the 17th century that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held...	Christiaan Huygens	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...	1686
Christiaan Huygens 170 foot refractor	20 cm	8"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - Aerial telescope Aerial telescope An aerial telescope is a type of very-long-focal-length refracting telescope built in the second half of the 17th century that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held...	Christiaan Huygens	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...	1686
Christiaan Huygens 210 foot refractor	19 cm	7.5"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - Aerial telescope Aerial telescope An aerial telescope is a type of very-long-focal-length refracting telescope built in the second half of the 17th century that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held...	Christiaan Huygens	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...	1686
Hooke's reflector	18 cm	7″	Reflector 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...	Robert Hooke Robert Hooke Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...	Great Britain	16??
Hevelius refractor	12 cm	4.7″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Johannes Hevelius Johannes Hevelius Johannes Hevelius Some sources refer to Hevelius as Polish:Some sources refer to Hevelius as German:Encyplopedia Britannica of the Royal Society was a councilor and mayor of Danzig , Pomeranian Voivodeship, in the Polish-Lithuanian Commonwealth...	Gdańsk Gdansk Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the... (Danzig), 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...	1645
Hevelius Scheiner's helioscope	6 cm	2.3″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Johannes Hevelius Johannes Hevelius Johannes Hevelius Some sources refer to Hevelius as Polish:Some sources refer to Hevelius as German:Encyplopedia Britannica of the Royal Society was a councilor and mayor of Danzig , Pomeranian Voivodeship, in the Polish-Lithuanian Commonwealth...	Gdańsk Gdansk Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the... (Danzig), 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...	1638
Galileo's 1620 telescope	3.8 cm	1.5″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Galileo Galilei Galileo Galilei Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...	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...	1638
Galileo's 1612 telescope	2.6 cm	1″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Galileo Galilei Galileo Galilei Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...	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...	1612
Galileo's 1609 telescope	1.5 cm	.62″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Galileo Galilei Galileo Galilei Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...	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...	1609
Hans Lippershey's telescope	? cm	.?″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Hans Lippershey Hans Lippershey Hans Lippershey , also known as Johann Lippershey or Lipperhey, was a German-Dutch lensmaker commonly associated with the invention of the telescope, although it is unclear if he was the first to build one.-Biography:...	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...	1608

Table of optical telescope progression historically

Chronological list of optical telescopes by historical significance, not overall size.

Name	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...	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,...	Significance	Site	Built
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″	Reflector 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... - 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	Worlds largest 2009	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... , Spain	2009
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 x 2 (22.8 m LBTI)	464.5″	glass mirror reflector 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... - Multi-mirror (2)	Worlds largest 2008 with Beam Combiner	Mount Graham International Observatory 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...
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...	9.2 m	362″	Reflector 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... - 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... ,91	First HET	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... , USA	1997
Keck 1	10 m	400″	Reflector 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... - 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	Worlds largest 1993	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	1993
Hubble 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... (HST)	2.4 m	94″	glass mirror reflector 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...	Largest Visible-light space based telescope	Low Earth orbit Low Earth orbit A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km... NASA NASA The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research... +ESA	1990
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″	glass mirror reflector 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...	Worlds largest 1976	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...	1976
McMath-Pierce Solar Telescope McMath-Pierce Solar Telescope The McMath-Pierce Solar Telescope is a 1.6-m f/54 reflecting solar telescope at Kitt Peak National Observatory in Arizona, USA. The building was designed by Myron Goldsmith and built in 1962. It is the largest telescope of its kind in the world and is named for astronomers Robert McMath and Keith...	1.61 m	63″	glass mirror reflector 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...	Largest solar telescope	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	1962
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″	glass mirror reflector 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...	Worlds largest 1948	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	1948
Samuel Oschin telescope Samuel Oschin telescope The Samuel Oschin telescope is a 48-inch aperture Schmidt camera at the Palomar Observatory in northern San Diego County, California. It consists of a 49.75-inch Schmidt corrector plate and a 72-inch mirror. The instrument is strictly a camera; there is no provision for an eyepiece to look...	1.22 m	48″	glass mirror reflector 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... - Schmidt camera Schmidt camera A Schmidt camera, also referred to as the Schmidt telescope, is a catadioptric astrophotographic telescope designed to provide wide fields of view with limited aberrations. Other similar designs are the Wright Camera and Lurie-Houghton telescope....	Worlds largest Schmidt camera 1948	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	1948
George Ritchey 40-inch (1 m)	102 cm	40″	glass mirror reflector 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...	First large Ritchey-Chrétien	Flagstaff Flagstaff Station United States Naval Observatory Flagstaff StationFlagstaff *Flagstaff railway station, Melbourne, AustraliaFlagstaff station can also be Television and Radio stations in and around Flagstaff, Arizona USA:... , Arizona (Washington, D.C. until 1955)	1934
Plaskett telescope	1.83 m	72″	glass mirror reflector 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...	designed as worlds largest but beaten by Hooker 100-Inch	Dominion Astrophysical Observatory Dominion Astrophysical Observatory The Dominion Astrophysical Observatory, located on Observatory Hill, in Saanich, British Columbia, was completed in 1918 by the Canadian government. Proposed and designed by John S... , Canada	1918
Hooker 100-Inch Telescope Mount Wilson Observatory The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles...	2.54 m	100″	glass mirror reflector 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...	Worlds largest 1917	Mt. Wilson Observatory; California	1917
Hale 60-Inch Telescope Mount Wilson Observatory The Mount Wilson Observatory is an astronomical observatory in Los Angeles County, California, United States. The MWO is located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles...	1.524 m	60″	glass mirror reflector 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...	the first of the "modern" large research reflectors, designed and located for precision imaging.	Mt. Wilson Observatory; California	1908
Great Paris Exhibition Telescope of 1900 Great Paris Exhibition Telescope of 1900 The Great Paris Exhibition Telescope of 1900, with an objective lens of 1.25 m in diameter, was the largest refracting telescope ever constructed. It was built as the centerpiece of the Paris Universal Exhibition of 1900. Its construction was instigated in 1892 by François Deloncle , a member of...	125 cm	49.21"	refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - achromat	largest refractor ever built, scraped after Exhibition.	Exposition Universelle (1900) Exposition Universelle (1900) The Exposition Universelle of 1900 was a world's fair held in Paris, France, from April 15 to November 12, 1900, to celebrate the achievements of the past century and to accelerate development into the next...	1900–1901
A.A. Common Andrew Ainslie Common Andrew Ainslie Common FRS was an English amateur astronomer best known for his pioneering work in astrophotography.-Biography:... 's 60-inch Ealing reflector	1.524 m	60″	glass mirror reflector 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...	Worlds largest glass mirror reflector 1889, sold to Harvard 1904, moved to South Africa 1920s (Boyden Observatory Boyden Observatory Boyden Observatory is a South African astronomical research observatory and science education centre.-History:The observatory was originally founded in 1889 by the Harvard University at Mount Hardvard near Lima, Peru, but relocated to Arequipa, Peru in October 1890.Significant work done at Arequipa... ) where it was largest telescope in the southern hemisphere.	Ealing Ealing Ealing is a suburban area of west London, England and the administrative centre of the London Borough of Ealing. It is located west of Charing Cross and around from the City of London. It is one of the major metropolitan centres identified in the London Plan. It was historically a rural village... , Harvard College Observatory Harvard College Observatory The Harvard College Observatory is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839... , Boyden Observatory Boyden Observatory Boyden Observatory is a South African astronomical research observatory and science education centre.-History:The observatory was originally founded in 1889 by the Harvard University at Mount Hardvard near Lima, Peru, but relocated to Arequipa, Peru in October 1890.Significant work done at Arequipa...	1889
Yerkes Refractor	102 cm	40″	refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - achromat	largest operational refractor	Yerkes Observatory Yerkes Observatory Yerkes Observatory is an astronomical observatory operated by the University of Chicago in Williams Bay, Wisconsin. The observatory, which calls itself "the birthplace of modern astrophysics," was founded in 1897 by George Ellery Hale and financed by Charles T. Yerkes... , USA	1897
A.A. Common's 36 inch Ealing reflector	91.4 cm	36″	glass mirror reflector 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...	First to prove fainter than naked eye astrophotography Astrophotography Astrophotography is a specialized type of photography that entails recording images of astronomical objects and large areas of the night sky. The first photographs of an astronomical object were taken in the 1840s, but it was not until the late 19th century that advances in technology allowed for... , sold, became Crossley Reflector Crossley telescope The Crossley telescope is an reflecting telescope located at Lick Observatory in the U.S. state of California.-History:Given to the observatory in 1895 by British politician Edward Crossley, it was rebuilt from the ground up as it was on a very flimsy mounting. It is still being used today in the...	A.A. Common Reflector, Britain / 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... , USA	1879
Great Melbourne Telescope Great Melbourne Telescope The Great Melbourne Telescope was built by Thomas Grubb in Dublin, Ireland in 1868, and installed at the Melbourne Observatory in Melbourne, Australia in 1869.The telescope had a speculum primary mirror, and was mounted on an equatorial mounting...	1.22 m	48″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...	Last large reflector with a speculum metal mirror, worlds largest equatorially mounted telescope for several decades.	Melbourne Observatory Melbourne Observatory Melbourne Observatory was founded in 1862 to serve as a scientific research institution for the rapidly growing city of Melbourne, the capital of the colony of Victoria. The observatory was tasked by the Victorian government with maintaining an accurate time reference for the colony through... , Australia	1868–1889
William Lassell 48-inch	1.22 m	48″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...		Malta Malta Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...	1861–1865
Leviathan of Parsonstown Leviathan of Parsonstown Leviathan of Parsonstown is the unofficial name of the Rosse six foot telescope. This is a historic reflecting telescope of 72 in aperture, which was the largest telescope in the world from 1845 until the construction of the 100 in Hooker Telescope in 1917...	1.83 m	72″	metal Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... - speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...	Worlds largest 1845	Birr Castle Birr Castle Birr Castle is a large castle in the town of Birr in County Offaly, Ireland. It is the home of the seventh Earl of Rosse, and as such the residential areas of the castle are not open to the public, though the grounds and gardens of the demesne are publicly accessible.-Ireland's Historic Science... ; Ireland Ireland Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...	1845–1908
William Lassell 24-inch	61 cm	24″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...		Liverpool Liverpool Liverpool is a city and metropolitan borough of Merseyside, England, along the eastern side of the Mersey Estuary. It was founded as a borough in 1207 and was granted city status in 1880... , England	1845
Great Dorpat Refractor (Fraunhofer) Dorpat/Tartu Observatory Tartu Observatory The Tartu Observatory is the largest astronomical observatory in Estonia. It is located on the Tõravere hill, about 20 km south-west of Tartu in Nõo Parish, Tartu County...	24 cm	9.6″	refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - achromat	"..the first modern, achromatic, refracting telescope."	Dorpat, Governorate of Estonia Governorate of Estonia The Governorate of Estonia or Estland, also known as the Government of Estonia or Province of Estonia, was a governorate of the Russian Empire in what is now northern Estonia.-Historical overview:...	1824
Rosse 36-inch Telescope	91.4 cm	36″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...		Birr Castle Birr Castle Birr Castle is a large castle in the town of Birr in County Offaly, Ireland. It is the home of the seventh Earl of Rosse, and as such the residential areas of the castle are not open to the public, though the grounds and gardens of the demesne are publicly accessible.-Ireland's Historic Science... ; Ireland Ireland Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...	1826
Herschel 40-foot 40-foot telescope William Herschel's 40-foot telescope, also known as the Great Forty-Foot telescope, was a reflecting telescope constructed between 1785 and 1789 at Observatory House in Slough, England. It used a 120 cm diameter primary mirror with a 12 m long focal length . It was the largest telescope in... (126 cm d.)	1.26 m	49.5″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...	Worlds largest 1789	Observatory House Observatory House Observatory House was an observatory in Slough, England. It was built, run and used by the astronomer William Herschel, and his sister Caroline. The famous '40-foot telescope' - at that time the largest in the world - was housed there in the late 18th century and early 19th century.The main house... ; England	1789–1815
Herschel 20-foot (47.5 cm d.)	47.5 cm	18.5″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...		Observatory House Observatory House Observatory House was an observatory in Slough, England. It was built, run and used by the astronomer William Herschel, and his sister Caroline. The famous '40-foot telescope' - at that time the largest in the world - was housed there in the late 18th century and early 19th century.The main house... ; England	1782
Rev John Michell's Gregorian reflector	75 cm	29.5″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... - Gregorian reflector Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	Worlds largest 1780	Yorkshire Yorkshire Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform... , Great Britain	1780–1789
Dollond Peter Dollond Peter Dollond was an English maker of optical instruments, the son of John Dollond. He is known for his successful optics business, and for the invention of the apochromat.-Biography:... Apochromatic Triplet	9.53 cm	3.75″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - apochromat	First apochromatic triplet	England	1763
Father Noel's Gregorian reflector	60 cm	23.5″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... - Gregorian reflector Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	Worlds largest 1761	Paris, France	1761
James Short's Gregorian reflector	50 cm	19.5"	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... - Gregorian reflector Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	Worlds largest 1750	Scotland Scotland Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...	1750
James Short's Gregorian reflector	38 cm	14″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... - Gregorian reflector Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	Worlds largest 1734	Scotland Scotland Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...	1734
Chester Moore Hall Chester Moore Hall Chester Moore Hall was a British lawyer and inventor who produced the first achromatic lenses in 1729 or 1733 .... 's Doublet	6.4 cm	2.5"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - achromat	First achromatic doublet	Great Britain	1733
Hadley's Reflector	15 cm	6″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...	First parabolic newtonian	Great Britain	1721
Christiaan Huygens 210 foot refractor	22 cm	8.5"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - Aerial telescope Aerial telescope An aerial telescope is a type of very-long-focal-length refracting telescope built in the second half of the 17th century that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held...	Worlds largest 1686	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...	1686
Christiaan Huygens 170 foot refractor	20 cm	8"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - Aerial telescope Aerial telescope An aerial telescope is a type of very-long-focal-length refracting telescope built in the second half of the 17th century that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held...	Worlds largest 1689	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...	1686
Christiaan Huygens 210 foot refractor	19 cm	7.5"	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses... - Aerial telescope Aerial telescope An aerial telescope is a type of very-long-focal-length refracting telescope built in the second half of the 17th century that did not use a tube. Instead, the objective was mounted on a pole, tree, tower, building or other structure on a swivel ball-joint. The observer stood on the ground and held...	Worlds largest 1686	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...	1686
Hooke's reflector	18 cm	7″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... - Gregorian reflector Gregorian telescope The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer James Gregory in the 17th century, and first built in 1673 by Robert Hooke...	First Gregorian	Great Britain	1674
Newton's Reflector Newton's Reflector The first reflecting telescope built by Sir Isaac Newton in 1668 is a landmark in the history of telescopes, being the first known successful reflecting telescope. It was the prototype for a design that later came to be called a newtonian telescope....	3.3 cm	1.3″	speculum metal mirror Speculum metal Speculum metal is a mixture of around two-thirds copper and one-third tin making a white brittle alloy that can be polished to make a highly reflective surface. It is used primarily to make different kinds of mirrors including early reflecting telescope optical mirrors... reflector 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...	First reflecting telescope	England (mobile)	1668
Hevelius refractor	12 cm	4.7″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Worlds largest 1645	Gdańsk Gdansk Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the... (Danzig), 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...	1645
Hevelius Scheiner's helioscope	6 cm	2.3″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Worlds largest 1638 & First Equatorial Equatorial mount An equatorial mount is a mount for instruments that follows the rotation of the sky by having one rotational axis parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras...	Gdańsk Gdansk Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the... (Danzig), 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...	1638
Galileo's 1620 telescope	3.8 cm	1.5″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Worlds largest 1638	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...	1638
Galileo's 1612 telescope	2.6 cm	1″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Worlds largest 1612	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...	1612
Galileo's 1609 telescope	1.5 cm	.62″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Worlds largest 1609	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...	1609
Hans Lippershey's telescope	? cm	.?″	Refractor Refracting telescope A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...	Worlds first recorded telescope	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...	1608

Legend

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Table of largest optical telescopes historically by overall aperture

Table of optical telescope progression historically

See also

External links