Large Telescopes

Operational

Aperture (meters)	Name	Location	Latitude; Longitude Altitude	Comments
10.4	Gran Telescopio Canarias	La Palma, Canary Islands, Spain	28 46 N; 17 53 W 2400 m	Observatorio del Roque de los Muchachos; segmented mirror based on Keck
10	Keck	Mauna Kea, Hawaii	19 50 N; 155 28 W 4123 m	each mirror composed of 36 segmentsoperated separately or in tandem as the Keck Interferometer
	Keck II
~10	SALT	South African Astronomical Observatory	32 23 S; 20 49 E; 1759 m	based on the HET design
9.2	Hobby-Eberly	Mt. Fowlkes, Texas	30 40 N; 104 1 W 2072 m	very inexpensive: spherical segmented mirror; fixed elevation; spectroscopy only
8.4	Large Binocular Telescope	Mt. Graham, Arizona	32 42 N; 109 53 W 3170 m	a pair of 8.4-m mirrors on one mount giving the light gathering of an 11.8m and eventually the resolution of a 23-m
8.3	Subaru	Mauna Kea, Hawaii	19 50 N; 155 28 W 4100 m	NAOJ
8.2	Antu	Cerro Paranal, Chile	24 38 S; 70 24 W 2635m	operated separately or as units of the VLT Interferometer
	Kueyen
	Melipal
	Yepun
8.1	Gillett	Mauna Kea, Hawaii	1950 N; 155 28 W 4100 m	aka Gemini North
	GeminiSouth	Cerro Pachon, Chile	30 20 S;70 59 W (approx) 2737 m	twin of Gemini North
6.5	MMT	Mt. Hopkins, Arizona	31 41 N; 110 53 W 2600 m
	San Pedro Mārtir Observatory	Arizona		To be completed in 2017
	Lockheed Martin Corp	Sunnyvale, CA
	Walter Baade	La Serena, Chile	29 00.2 S; 4 42 48 W 2282 m	aka Magellan I;Las Campanas Obs.
	Landon Clay			aka Magellan II
6	Bolshoi Teleskop Azimutalnyi	Nizhny Arkhyz, Russia	43 39 N; 41 26 E 2070m	Large Altazimuth Telescope
	LZT	British Columbia, Canada	49.28 N; 122.57 W 395m	Liquid mirror, points only at the zenith; UBC
5	Hale	Palomar Mountain, California	33 21 N; 116 52 W 1900 m
4.2	William Herschel	La Palma, Canary Islands, Spain	28 46 N; 17 53 W 2400 m	Observatorio del Roque de los Muchachos
	SOAR	Cerro Pachon, Chile	70 44 W; 30 14 S 2738 m	Brazil/USA; CTIO
	LAMOST	Xinglong Station, China	105 50 E ? , 40 23 N 950 m	Beijing Astronomical Observatory; wide field spectroscopy
4	Victor Blanco	Cerro Tololo, Chile	30 10 S;70 49 W 2200 m	CTIO
	Vista	Cerro Paranal, Chile	24 36 S; 70 23 W 2635m	wide field survey scope
3.9	Anglo-Australian	Coonabarabran, NSW, Australia	31 17 S;149 04 E	Siding Spring Obs.
3.8	Mayall	Kitt Peak, Arizona	31 57 N; 111 37 W 2100 m	NOAO
	UKIRT	Mauna Kea, Hawaii	19 50 N; 155 28 W 4200 m	dedicated to infrared
3.7	AEOS	Maui, Hawaii	20 42 30 N; 156 15 29 W 3058 m	mostly military
3.6	"360"	Cerro La Silla, Chile	29 15 S; 70 44 W 2400 m	European Southern Obs.
	Canada-France-Hawaii	Mauna Kea, Hawaii	19 50 N; 155 28 W 4200 m
	Telescopio Nazionale Galileo	La Palma, Canary Islands, Spain	28 45 N; 17 53 W 2387 m	Italian
3.5	MPI-CAHA	Calar Alto, Spain	37 13 N; 2 33 W 2200 m
	New Technology	Cerro La Silla, Chile	29 15 S; 70 44 W 2400 m	European Southern Obs.
	ARC	Apache Point, New Mexico	32 47 N; 105 49 W 2788 m	mostly remote controlled
	WIYN	Kitt Peak, Arizona	31 57 N; 111 37 W 2100 m	Wisconsin, Indiana, Yale, NOAO
	Starfire	Kirtland AFB, New Mexico	1900 m	military
3	Shane	Mount Hamilton, California	37 21 N; 121 38 W 1300 m	Lick Observatory
	NASA IRTF	Mauna Kea, Hawaii	19 50 N; 155 28 W 4160 m	infrared
2.7	Harlan Smith	Mt. Locke, Texas	30 40 N; 104 1 W 2100 m	McDonald Obs.; see also
2.6	BAO	Byurakan, Armenia	40 20N; 44 17 E 1405 m	Byurakan Astrophysical Observatory
	Shajn	Crimea, Ukraine	44 44 N; 34 E 600 m	Crimean Astrophysical Observatory
2.5	J-PAS	Sierra de Javalambre, Spain		1.2 Giga-pixel camera
	Hooker	Mt. Wilson, California	34 13N; 118 4 W 1700 m	built in 1917
	Isaac Newton	La Palma, Canary Islands, Spain	28 45 N; 17 53 W 2382 m	Crimean Astrophysical Observatory
	Nordic Optical
	du Pont	La Serena, Chile	29 00.2 S; 4 42 48 W 2282 m	Las Campanas Obs.
	Sloan Digital Sky Survey	Apache Point, New Mexico	32 47 N; 105 49 W 2788 m	huge wide-field detector
2.45	CHARA	Mt. Wilson, California	34 13N; 118 4 W 1700 m	interferometer using 6 1-m scopes
2.4	Hiltner	Kitt Peak, Arizona	31 57 N; 111 37 W 2100 m	MDM Observatory
	Lijiang	Lijiang City, China	26 52 N; 100 14 E 3250 m	Yunnan Observatory(near Dayan)
	Hubble Space Telescope	Low Earth orbit!	varies 600km
2.3	WIRO	Jelm Mtn., Wyoming	41 03 N; 106 00 W 2900 m	infrared
	ANU	Coonabarabran, NSW, Australia	31 17 S;149 04 E	Siding Spring Obs.
	Bok	Kitt Peak, Arizona	31 57 N; 111 37 W 2100 m	Steward Obs
	Vainu Bappu	Kavalur, India	12 34 N; 78 50 E 700 m	Indian Institude of Astrophysics
	Aristarchos	Mt. Helmos, Greece	37 59 N; 22 12 E 2340 m	National Observatory of Athens
2.2	ESO-MPI	Cerro La Silla, Chile	29 15 S; 70 44 W 2335 m
	MPI-CAHA	Calar Alto, Spain	37 13 N; 2 33 W 2200 m
	UH	Mauna Kea, Hawaii	19 50 N; 155 28 W 4200 m
3x1.65	Infrared Spatial Interferometer	Mt. Wilson, California	34 13N; 118 4 W 1700 m	interferometer using 3 1.65m infrared scopes

Also

2.1 Kitt Peak
2.1 McDonald (Struve)
2.1 INAOE, Puebla, Mexico
2.1 UNAM, San Pedro Martir, Mexico
2.1 El Leoncito, Argentina
2.0 Ondrejov, Czech Republic
2.0 Tusi Astronomical Obs., Shemakha, Azerbaijan
2.0 Hanle, India (a few hundred meters higher than Mauna Kea)
2.0 (Schmidt) Tautenburg Germany
2.0 Ukrainian Academy of Sciences, Terskel, Caucasus
2.0 MAGNUM (Haleakala, may still be in progress)
2.0 Lyot, Pic-du-Midi, France
2.0 Faulkes Telescope North
2.0 Faulkes Telescope South

Under Construction

Aperture	Name	Location	Comments
21.4 (7x8.4)	Giant Magellan Telescope	Las Campanas, Chile	six off-axis segments plus one central segment form one optical surface
8	LSST	Cerro Pachon, Chile	aka Dark Matter Telescope; a fast wide field survey scope
4.2	DCT	Happy Jack, Arizona	Lowell Observatory wide field telescope
2.5	SOFIA/a>	stratosphere	airborne infrared
	VST	Cerro Paranal, Chile	wide field survey scope
2.4	Automated Planet Finder Telescope	Mount Hamilton, California	Lick Observatory
4x1.8	Pan-STARRS	Hawaii	Four separate telescopes; optimized for surveys; cheaper than LSST; PS1 first light was Aug 2007
2.4+10x1.4	Magdalena Ridge Observatory	Socorro, New Mexico	one single scope plus 10 mirror interferometer

Extremely Large Telescope Studies

Aperture	Name	Comments
50	Euro50
42	E-ELT	European Extremely Large Telescope
30-50	MaxAT
~40	LAMA	array of liquid mirrors
30	TMT	Thirty Meter Telescope (was CELT, VLOT, GSMT)
Others

Other interesting projects

Aperture	Name	Location	Comments
42	LAMA	Chile	liquid mirror array
25	Cornell Atacama Telescope	Atacama, Chile	optimized for far IR, next to ALMA
6.5	JWST	L2 Halo orbit	aka NGST; cost reduced from initial 8m plans
4	ATST	Haleakala, Hawaii	Advanced Technology Solar Telescope
2.5	The MLO 100 inch	Mt. Laguna, CA
2	Indian Astronomical Observatory	Hanle, India	4500m altitude
1.86	Dominion Astrophysical Observatory	Victoria, Canada	was once (briefly) the largest telescope in the world
1.8	The Leviathan of Parsonstown	Birr, Ireland	Lord Rosse's famous scope restored
1.5	Hexapod Telescope	La Silla	unique mount utilizing 6 hydraulic "legs"
1.2	Samuel Oschin Telescope	Palomar Mountain, California	found the "tenth planet"
1	Yerkes Observatory	Williams Bay, Wisconsin	world's largest refractor

References

AstroWeb
Reflector telescopes
Refractor telescopes
Orbiting Astronomical Telescopes
Amateur Observatories
Observatories with public viewing programs
EOS Technologies, supplier of 2m class telescopes

Bill Arnett; last updated: 2010 Aug 14 ; additions / corrections / updates appreciated

The World’s Largest Optical Telescopes

Operational

Also

Under Construction

Extremely Large Telescope Studies

Other interesting projects

References