List of largest optical refracting telescopes

Here is a list of the largest optical refracting telescopes sorted by lens diameter and focal length.

The largest practical functioning refracting telescope is the Yerkes Observatory 40 inch (102 cm) refractor, used for astronomical and scientific observation for over a century.

Most are classical Great refractors, which used achromatic doublets on an equatorial mount. However, other large refractors include a 21st-century Solar telescope which is not directly comparable because it uses a single element non-achromatic lens, and the short-lived Great Paris Exhibition Telescope of 1900. It used a 78-inch (200 cm) Focault siderostat for aiming light into the Image-forming optical system part of the telescope, which had a 125 cm diameter lens. Using a siderostat incurs a reflective loss. Larger meniscus lenses have been used in later catadioptric telescopes which mix refractors and reflectors in the image-forming part of the telescope. As with reflecting telescopes, there was an ongoing struggle to balance cost with size, quality, and usefulness.

Name/Observatory	Location at debut	Modern location name or fate	Lens diameter	Focal length	Built	Comments
Yerkes Observatory^[1]	Williams Bay, Wisconsin, USA	-	102 cm (40″)	19.4 m (62′)	1897	Largest in current operation.^[2]
Great Paris Exhibition Telescope of 1900	Paris 1900 Exposition	Dismantled 1900	125 cm (49.21")	57 m (187 feet)	1900	Fixed lens, scrapped. Aimed via a 2m reflecting siderostat
Swedish 1-m Solar Telescope, ORM	La Palma, Spain	-	98 cm (39.37")	15 m	2002	Single element non-achromatic objective^[3] combined with reflective Adaptive optics and a Schupmann corrector.
James Lick telescope Lick Observatory	Mount Hamilton, California, USA	-	91 cm (36″)	17.6 m	1888
Grande Lunette Paris Observatory	Meudon, France	-	83 cm + 62 cm (32.67" + 24.40")	16.2 m	1891	Double telescope
Großer Refraktor Astrophysical Observatory Potsdam	Potsdam, Deutsches Kaiserreich	Potsdam, Germany	80 cm + 50 cm (31.5"+19.5")	12.0 m	1899	Double telescope
Grande Lunette Nice Observatory	Nice, France	since 1988 Côte d'Azur Observatory	77 cm (30.3″) ^[4]^[5]	17.9 m	1886	Bischoffscheim funded
William Thaw Telescope Allegheny Observatory, University of Pittsburgh	Pittsburgh, Pennsylvania, USA	-	76 cm (30″)	14.1 m	1914	Brashear made, photographic^[6]
Pulkovo observatory	Saint Petersburg, Russian Empire	Destroyed	76 cm (30″)	12.8 m (42 feet)	1885	Destroyed during WWII, only lens (made by Alvan Clark & Sons) survives.
28-inch Grubb Refractor Royal Greenwich Observatory	Greenwich, London, Great Britain	-	71 cm (28″)	8.5 m	1894
Großer Refraktor Vienna Observatory	Vienna, Austrian Empire	Vienna, Austria	69 cm (27" )	10.5 m	1880	Largest refractor in 1880 ^[7]
Great Treptow Refractor Treptow Observatory	Berlin, Germany	-	68 cm (26.77")	21 m	1896	renamed Archenhold Observatory 1946
Leander McCormick Observatory	Charlottesville, Virginia, USA	-	66 cm (26" )	9.9 m	1884	completed c. 1874, installed 1884
U.S. Naval Observatory	Foggy Bottom Washington, DC, USA	moved to Northwest, Washington, D.C., 1893	66 cm (26")	9.9 m	1873	Largest refractor in 1873. Alvan Clark & Sons mounting replaced with Warner & Swasey mounting in 1893.
Royal Greenwich Observatory	Herstmonceux, Great Britain	-	66 cm (26")	6.82 m	1896
Yale-Columbia Refractor Yale Southern Station	Johannesburg, Union of South Africa	Relocated 1952	66 cm (26")	10.8 m	1925–1952	Yale-Columbia Refractor moved to Mount Stromlo Observatory in 1952, same telescope as following entry.
Yale-Columbia Refractor Mount Stromlo Observatory	Mount Stromlo, Australia	Destroyed 2003	66 cm (26")	10.8 m	1952	Yale-Columbia Refractor - Previously located in South Africa. Relocated to Australia in 1952. Destroyed by bush fire on January 18, 2003.^[8]
65 cm Zeiss Refractor, Pulkovo observatory	Germany^[9]	Saint Petersburg, Russia	65 cm (25.59″)	10.413 m	1954	War reparation from Germany^[9] In Pulkovo since 1954.
Llano del Hato National Astronomical Observatory	Llano del Hato, Venezuela	-	65 cm (25.6″)	10.5 m	1955
Belgrade Observatory ^[10]	Belgrade, Kingdom of Serbia	Belgrade, Serbia	65 cm (25.6″)	10.55 m	1932	Zeiss made lens, same as at Berlin Observatory
Hida Observatory	Gifu, Japan	-	65 cm (25.6″)	10.50 m	1972
Observatory History Museum Mitaka 65 cm	Mitaka, Tokyo, Japan	-	65 cm (25.6″)		1929	Carl Zeiss Jena
Berlin-Babelsberg Observatory Berliner Sternwarte Babelsberg	Berlin, Germany		65 cm (26 in)	10.12 m (33 ft)	1914	Berlin Observatory just moved to Potsdam-Babelsberg in 1913; Zeiss lens
Newall Refractor National Observatory of Athens	UK	Athens, Greece since 1957	62.5 cm (24.5″)	8.86 m (29 ft)	1869	Built by Thomas Cooke for Robert Stirling Newall. First located at his estate; donated and relocated to Cambridge Observatory in 1889; donated to Athens Observatory and relocated to Mt. Penteli in Greece in 1957. Currently used only for educational purposes as part of the visitor center.
Lowell Observatory	Arizona, USA	-	61 cm (24″)	9.75 m (32 ft)	1894	Alvan Clark & Sons telescope
Sproul Observatory	Pennsylvania, USA	-	61 cm (24″)	11.0 m (36 ft)	1911
Craig telescope	Wandsworth Common, London	Dismantled 1857	61 cm (24″)	24.5 m (80 feet)	1852	Problem with lens figuring ^[11]
Grubb Parsons Double Refractor	Saltsjöbaden, Sweden	-	60 + 50 cm (23.6″ + 19.7")	8.0 m	1930	Stockholms Observatory in Saltsjöbaden
Radcliffe Double Refractor University of London Observatory	Oxford, UK	Mill Hill, London	60 + 45 cm (23.6″ + 18")	7.0 m	1901	Obtained from the Radcliffe Observatory and installed at ULO in 1938
Zeiss Double Refractor Bosscha Observatory	Bandung, Dutch East Indies	Bandung, Indonesia	60 cm (23.6″)	10.7 m	1928
Der Große Refraktor (Great Refractor) Hamburg Observatory	Bergedorf, Germany	-	60 cm (23.6″)	9 m	1911
Halstead Observatory	Princeton, USA	Roper Mountain Science Center,^[12] Greenville, SC	58.4 cm (23″)	9.8 m (32 ft)	1881	by Alvan Clark & Sons
Chamberlin Observatory	Colorado, USA	-	50 cm (20″)	8.5 m (28 ft)	1891	First Light 1894
Van Vleck Observatory	Connecticut, USA	-	50 cm (20″)	8.4 m (27.5 ft)	1922
Chabot Observatory		Oakland, California, USA (2000)	50 cm (20″)	8.5 m (28 ft)	1914	"Rachael" Warner & Swazey Company (Optics John A Brashear Company) Refurb in 2000 and moved to present location.
Carnegie Double Astrograph Lick Observatory	Mount Hamilton, California, USA	not in service threatened with removal	50 cm (20″)	4.67 m (14 ft)	1941	F7.4
Imperial Observatory	Straßburg, German Empire	Strasbourg, France	48.5 cm (19.1″)	7 m (23 ft)	1880 ^[13]	Then largest in German Empire
18½-in Dearborn Observatory Refractor	Chicago, USA	Evanston, USA	47 cm (18.5″)		1862	by Alvan Clark & Sons
Wilder Observatory	Amherst College, Amherst, MA, USA	-	46 cm (18″)	(25 ft)	1903	by Alvan Clark & Sons
Flower Observatory	Philadelphia, USA	-	46 cm (18″)	6.7 m (22.6 ft)	1896
Royal Observatory	Cape Colony, British Empire	South Africa	46 cm (18″)	6.7 m (22.6 ft)	1897	^[14]
Gran Ecuatorial Gautier Telescope La Plata Astronomical Observatory	La Plata, Argentina	-	43.3 cm (17″)	9,7 m	1894	Gautier
Brashear Refractor, Goodsell Observatory	Northfield, Minnesota, USA	-	41.15 cm (16.2″)		1890	by John Brashear
Herget Telescope Cincinnati Observatory	Cincinnati, Ohio	-	40.64 cm (16″)		1904	by Alvan Clark & Sons
Dorides Refractor ^[15] National Observatory of Athens	Athens, Greece	Athens, Greece	40 cm (16″)	5,08 m	1901	by Gautier ^[16]
Washburn Observatory	Madison, Wisconsin, USA	-	39.5 cm (15.56″)	6.7 m (22.6 ft)	1881	by Alvan Clark & Sons
Harvard Great Refractor Harvard College Observatory ^[17]	Cambridge, Massachusetts, USA	-	38 cm (15″)		1847	largest telescope in America for 20 years ^[18]
Gran Ecuatorial Observatorio Astronómico Nacional	Tacubaya, México	-	38 cm (15")	4.8 m	1885	by Howard Grubb
Lunette Arago Paris Observatory	Paris, France	-	38 cm (15")	9 m	1883	by Gautier and Henry brothers
Telescopio Amici Osservatorio Astrofisico di Arcetri	Florence, Italy	-	36 cm	5 m	1872	28 cm lens by G. B. Amici substituted by Zeiss lens in 1926. Currently used only for educational purposes.
Photographic Refractor Leiden Observatory	Leiden, Netherlands	-	34 cm + 15 cm (13.4″ + 5.9")	524 cm	1897	Double telescope by Gautier and Henry brothers
Dominion Observatory Refractor Dominion Observatory	Ottawa, Canada	Moved to Helen Sawyer-Hogg Observatory (Canada Science and Technology Museum, Ottawa) in 1974 ^[19]	38.1 cm (15″)	571.5 cm	1905	Original achromat doublet by John Brashear replaced with apochomat triplet by Perkin-Elmer in 1958. Currently used for education and outreach.
Fitz-Clark Refractor Allegheny Observatory, University of Pittsburgh	Pittsburgh, Pennsylvania, USA	-	32.02 cm (13")	4.62	1861	Fitz made, visual/photographic. In 1895 Established that Saturn's Rings to be made up of particles and not solid.^[6]
Bamberg Refractor Urania Observatory (Berlin)	Berlin-Moabit, Prussia	Berlin, Germany	31.4 cm (12.36")	5 m	1889	then biggest in Prussia, moved to Insulaner Wilhelm-Foerster Observatory in 1963 ^[20]
Grubb refractor, Keele Observatory	Oxford, England	Keele University, England (since 1962), in use for the public	31.0 cm (12.25")	4.39 m	1874	Still awaiting the reunion with its 19th-century camera used in the Carte du Ciel project and to prove Einstein's general relativity theory during the 1919 solar eclipse.
Ladd Observatory, Brown University	Providence, Rhode Island, USA	Still in use for instruction and public education	30 cm (12″) 12.0-inch (300 mm)	4.57 m (15 ft)	1891	Lens designed by Charles S. Hastings and made by John Brashear; telescope mount by George N. Saegmuller
Irving Porter Church Memorial Telescope Fuertes Observatory	Ithaca, New York	Still used for instruction and public outreach.	30 cm (12″)	-	1922	Optics by John Brashear, mounting by Warner & Swasey.
Silesian Planetarium and Astronomical Observatory	Katowice/Chorzów, Silesia, Poland		30 cm (12")^[21]	4.5 m	1955	Largest and oldest Planetarium and Astronomical Observatory in Poland.^[22] The 3rd largest in Eastern Europe (east of Germany), after Pulkovo Observatory in Saint Petersburg, Russia and Belgrade Observatory in Belgrade, Serbia
Urania Sternwarte (Zurich)	Zurich, Switzerland	-	30 cm (12″)	5.05 m	1907	by Fraunhofer and Zeiss
University of Illinois Observatory	Urbana, Illinois, USA	-	30 cm (12″)		1896	by John Brashear, National Historic Landmark, still used for instruction
Jewett Observatory	Pullman, Washington, USA	Used for instruction and pleasure	30 cm (12")	4.57 m (15')	Assembled from older parts 1953 ^[23]	Alvan Clark & Sons
Mitchell Telescope Cincinnati Observatory	Cincinnati, Ohio, USA	-	28 cm (11″)		1843	Merz & Mahler; Oldest professional telescope still used weekly by the public^[24]
Brashear Refractor Nicholas E. Wagman Observatory	Pittsburgh, Pennsylvania, USA	-	28 cm (11″)		1910	John Brashear, Amateur Astronomers Association of Pittsburgh ^[25] ll
Repsold Refractor (10-duims) Leiden Observatory	Leiden, Netherlands	-	26.6 cm (10.5″)	399,5 cm	1885	Repsold and Sons, optics by Alvan Clark & Sons
Mills Observatory		Dundee, Scotland (1951)	25 cm (10″)		1871	by T. Cooke & Sons. Training telescope at St. Andrews 1938-1951
Coats Observatory		Paisley, Scotland (1898)	25 cm (10″)		1898	by Howard Grubb. Replaced 5" refractor by Thomas Cooke, installed in 1883.]].
Quito Astronomical Observatory	Quito	La Alameda park	24 cm		1875	An operational 1875 Merz Telescopes and one of the Oldest Observatories in South America, founded in 1873.
Fraunhofer-Refraktor Berlin Observatory	Berlin-Kreuzberg, Deutsches Kaiserreich	Moved 1913 to Munich, Germany	24 cm (9.6″)	4 m (13.4′)	1835	Used to discover Neptune; in Deutsches Museum, München since 1913^[26]
Hume Cronyn Memorial Observatory Named in memory of Hume Blake Cronyn	University of Western Ontario London, Ontario, Canada	-	25.4 cm (10″)	4.37 m (172")	1940	Built by Perkin Elmer Corp. Second largest refractor in Canada. Continues as Canada's oldest public astronomy venue.
Great Dorpat Refractor (Fraunhofer) Dorpat/Tartu Observatory	Dorpat, Governorate of Livonia	Tartu, Estonia	24 cm (9.6″)	4 m (13.4′)	1824	"..the first modern, achromatic, refracting telescope." ^[27]^[28]