Refracting telescopes use a lens to focus light. The Swedish 1-m Solar Telescope, with a lens diameter of 43 inches, is technically the largest, with 39 inches clear for the aperture.The second largest refracting telescope in the world is the Yerkes Observatory 40 inch (102 cm) refractor, used for astronomical and scientific observation for over a century. The next largest refractor telescopes are the James Lick telescope, and the Meudon Great Refractor.[1]
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.
This list includes some additional examples, such as the Great Paris telescope, which also used a mirror, and some solar telescopes which may have more complicated optical configurations. The SST has an optical aperture of 98 cm (39.37"), although the lens itself is 110 cm (43.31"). It is a single element lens whereas most of this list are doublets, with a crown and flint lens elements.
| Name/Observatory | Location at debut | Modern location name or fate | Lens diameter | Built | Comments | Image | ||
|---|---|---|---|---|---|---|---|---|
| Dismantled 1900 | 125 cm (49.21") | 57 m (187 ft) | 1900 | |||||
| - | 110 cm (43") total diameter98 cm (39") clear aperture | 15 m | 2002 | Single element non-achromatic objective[2] combined with reflective Adaptive optics and a Schupmann corrector. The lens is 110 cm in diameter stopped down to 98 cm (39"). | ||||
| Yerkes Observatory[3] | - | 1.02 m (40") | 19.4 m (62 ft) | 1897 | Largest in current operation.[4] | |||
| - | 91 cm (36") | 17.6 m | 1888 | |||||
| - | 83 cm + 62 cm (32.67"+24.41") | 16.2 m | 1891 | Double telescope | ||||
| 80 cm + 50 cm (31.5"+19.5") | 12.0 m | 1899 | Double telescope by Repsold and Sons, optics by Steinheil | |||||
| Nice, France | since 1988 Côte d'Azur Observatory | 77 cm (30.3")[5] [6] | 17.9 m | 1886 | Bischoffscheim funded | |||
| - | 76 cm (30") | 14.1 m | 1914 | Brashear made, photographic[7] | ||||
| Destroyed | 76 cm (30") | 12.8 m (42 feet) | 1885 | Destroyed during WWII, only lens (made by Alvan Clark & Sons) survives. | ||||
| - | 71 cm (28") | 8.5 m | 1894 | |||||
| Rolfscher Refraktor[8] | - | 70 cm (27.6") | 20.8 m | 1949 | Single element non-achromatic objective with Schupmann corrector. | |||
| Großer Refraktor Vienna Observatory | 69 cm (27") | 10.5 m | 1880 | Largest refractor in 1880, by Grubb[9] | ||||
| Great Treptow Refractor Treptow Observatory | - | 68 cm (26.77") | 21 m | 1896 | renamed Archenhold Observatory 1946 | |||
| Innes Telescope | Observatory Johannesburg, South Africa | Observatory Johannesburg, South Africa | 67 cm (26.5") | 11.6 m | 1909-1925 | Still in operation for educational purposes. By Grubb | ||
| Yale-Columbia Refractor Yale Southern Station | 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. | |||
| 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.[10] | ||||
| - | 66 cm (26") | 9.9 m | 1884 | completed c. 1874, installed 1884 | ||||
| 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. | ||||
| Thompson 26-inch Refractor[11] | Royal Observatory, Greenwich, Great Britain[12] | 66 cm (26") | 6.82 m | 1896 | Manufactured by Sir Howard Grubb as a gift from Sir Henry Thompson; originally used at Greenwich on the same mount as a 30 inch reflector | |||
| - | 65 cm (25.6") | 10.6 m | 1955 | |||||
| Belgrade Observatory[13] | 65 cm (25.6") | 10.55 m | 1932 | Zeiss made lens, same as at Berlin Observatory | ||||
| Hida Observatory | Gifu, Japan | - | 65 cm (25.6") | 10.5 m | 1972 | |||
| Germany[14] | 65 cm (25.6") | 10.413 m | 1954 | War reparation from Germany In Pulkovo since 1954. | ||||
| Observatory History Museum Mitaka 65 cm | Mitaka, Tokyo, Japan | - | 65 cm (25.6") | 10.21 m | 1929 | Carl Zeiss Jena | ||
| Berlin-Babelsberg Observatory Berliner Sternwarte Babelsberg | Berlin, Germany | 65 cm (26") | 10.12 m (33 ft) | 1914 | Berlin Observatory just moved to Potsdam-Babelsberg in 1913; Zeiss lens | |||
| Newall Refractor[15] 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. | ||
| Dismantled 1857 | 61 cm (24") | 24.5 m (80 ft) | 1852 | Problem with lens figuring[16] | ||||
| Pennsylvania, USA | Dismantled July 2017 | 61 cm (24") | 11.0 m (36 ft) | 1911 | Currently under restoration to be re-installed in Northwest Arkansas[17] | |||
| Arizona, USA | - | 61 cm (24") | 9.75 m (32 ft) | 1894 | Alvan Clark & Sons telescope | |||
| Einstein Tower[18] | Potsdam, Germany | - | 60 cm (23.6") | 14 m | 1924 | |||
| 60 cm (23.6") | 10.7 m | 1928 | ||||||
| Großer Refraktor (Great Refractor)[19] Hamburg Observatory | - | 60 cm (23.6") | 9 m | 1911 | by Repsold and Sons, optics (visual + photographic lens) by Steinheil | |||
| Grubb Parsons Double Refractor | Saltsjöbaden, Sweden | - | 60 + 50 cm (23.6" + 19.7") | 8.0 m | 1930 | Stockholm Observatory in Saltsjöbaden | ||
| 60 + 45 cm (23.6" + 18") | 7.0 m | 1901 | Obtained from the Radcliffe Observatory and installed at UCLO (then known as "ULO") in 1938 | |||||
| Halstead Observatory | Princeton, USA | 58.4 cm (23") | 9.8 m (32 ft) | 1881 | ||||
| Colorado, USA | - | 50 cm (20") | 8.5 m (28 ft) | 1891 | First Light 1894 | |||
| Oakland, California, USA (2000) | 50 cm (20") | 8.5 m (28 ft) | 1914 | "Rachel", Warner & Swazey Company (Optics John A Brashear Company) Refurbished in 2000 and moved to present location. | ||||
| Connecticut, USA | - | 50 cm (20") | 8.4 m (27.5 ft) | 1922 | ||||
| Retired? | 50 cm (20") x 2 | 4.67 m (14 ft) | 1941/1962 (2nd lens) | F7.4 | ||||
| 49 cm (19.29") | 7 m (22.97 ft) | 1882 | Largest refracting telescope in Italy | |||||
| Strasbourg, France | 48.5 cm (19.1") | 7 m (23 ft) | 1880[21] | Then largest in German Empire | ||||
| 18½-in Dearborn Observatory Refractor | Chicago, USA | Evanston, USA | 47 cm (18.5") | 1862 | ||||
| - | 46 cm (18.4") | 9.7 m | 1921 | T. Cooke & Sons[22] [23] | ||||
| Amherst College, Amherst, Massachusetts, USA | - | 46 cm (18") | (25 ft) | 1903 | ||||
| Flower Observatory | Philadelphia, USA | 46 cm (18") | 6.7 m (22.6 ft) | 1894 | From 2016 operational at Lake Tekapo, New Zealand. | |||
| Royal Observatory | 46 cm (18") | 6.7 m (22.6 ft) | 1897 | [24] | ||||
| Cooke-Zeiss Refractor, Royal Observatory of Belgium[25] | - | 45 cm (17.7") | 6.99 m | 1891/1932 | by Cooke & Sons, original 38 cm lens by Merz replaced by 45 cm lens from Zeiss 1932 | |||
| - | 43.3 cm (17") | 9,7 m | 1894 | Gautier | Telescopio refractor Gran Ecuatorial Gautier en La Plata]] --> | |||
| Northfield, Minnesota, USA | - | 41.15 cm (16.2") | 1890 | by John Brashear | ||||
| - | 40.64 cm (16") | 1904 | ||||||
| Castel Gandolfo, Italy | - | 40 cm (16") | 6.0 m | 1881 | by Zeiss | |||
| Dorides Refractor[26] National Observatory of Athens | Athens, Greece | Athens, Greece | 40 cm (16") | 5,08 m | 1901 | by Gautier[27] | ||
| Madison, Wisconsin, USA | In regular use for education and general public. | 39.5 cm (15.56") | 6.7 m (22.6 ft) | 1881 | ||||
| Ottawa, Ontario, Canada | Moved to Helen Sawyer-Hogg Observatory (Canada Science and Technology Museum, Ottawa) in 1974[28] | 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. | |||
| - | 38 cm (15") | 9 m | 1883 | by Gautier and Henry brothers | ||||
| - | 38 cm + 38 cm (15" + 15") | 6 m + 4 m | 1904 | Double telescope by Mailhat, Paris | ||||
| Gran Ecuatorial Observatorio Astronómico Nacional | Tacubaya, México | - | 38 cm (15") | 4.8 m | 1885 | by Howard Grubb | ||
| Harvard Great Refractor Harvard College Observatory[29] | Cambridge, Massachusetts, USA | - | 38 cm (15") | 6.9 m | 1847 | largest telescope in America for 20 years[30] | ||
| Rescued to Leningrad city in WWII (?) | 38 cm (15") | 6.9 m | 1839 | (original) twin of the Harvard Great Refractor | ||||
| - | 36.6 cm | 7.66 m | 1887 | |||||
| - | 36 cm | 5 m | 1872 | 28 cm lens by G. B. Amici substituted by Zeiss lens in 1926. Currently used only for educational purposes. | ||||
| - | 34 cm + 15 cm (13.4" + 5.9") | 524 cm | 1897 | Double telescope by Gautier and Henry brothers | ||||
| Astrograph Vienna Observatory | Vienna, Austrian Empire | Vienna, Austria | 34 cm + 26 cm (13.3" + 10.2") | 3.4 m + 3.4 m | 1885 | Double telescope by Steinheil | ||
| Perth Astrograph, Perth Observatory[31] | Old Perth Observatory, Mount Eliza, Western Australia | Perth Observatory, Bickley, Western Australia. Used for public education and outreach | 33 cm (13") | 3.34 m | 1897 | Designed and built by Howard Grubb & Co. Relocated to Bickley ~1966. The original telescope (both camera and guide scopes), mount and dome were re-erected at Bickley | ||
| - | 32.02 cm (13") | 4.62 | 1861 | Fitz made, visual/photographic. In 1895 established that Saturn's Rings are made up of particles and not solid. | ||||
| H. Fitz-H.G. Fitz Refractor Henry Ruthurfurd, Private Observatory | - | 32.02 cm (13") | 4.62 | 1864 | Fitz made, visual/photographic. Started by Henry, finished by son Henry Giles | |||
| Bamberg Refractor Urania Observatory (Berlin) | Berlin, Germany | 31.4 cm (12.36") | 5 m | 1889 | then biggest in Prussia, moved to Insulaner Wilhelm Foerster Observatory in 1963[32] | |||
| H. Fitz 12.6" refractorDetroit Observatory in Ann Arbor | Ann Arbor, Michigan, USA | 32 cm | 508 cm (200") | 1857 | The telescopes were restored to functionality as part of the University of Michigan's 2009 International Year of Astronomy celebration. Viewing nights and open houses[33] have been running since then. | |||
| Grubb refractor, Keele Observatory[34] | 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. | ||
| South Telescope, Dunsink Observatory | Dublin, Ireland | Dublin, Ireland | 30 cm (12") | 1868 | by Grubb, the telescope is still used for various outreach activities | |||
| Northumberland Telescope,[35] Institute of Astronomy, Cambridge University | Cambridge, England | Still in use by Cambridge University Astronomical Society and Cambridge Astronomical Association | 30 cm (12") | 5.95m | 1833 | Original lens 11.6" made by Cauchoix of Paris, replaced on 150th anniversary by 12" lens designed by R.V. Willstrop,[36] and made by A.E. Optics of Cambridge.[37] | ||
| Urania Sternwarte (Zurich) | - | 30 cm (12") | 5.05 m | 1907 | by Zeiss | |||
| - | 30 cm (12") | 5.03 m | 1931 | by Zeiss | ||||
| Clark-Refraktor[38] Vienna Observatory | Vienna, Austrian Empire | Vienna, Austria | 30 cm (12") | 5.06 m | 1880 | by Clark and Sons | ||
| - | 30 cm (12") | 5.0 m | 1924 | by Zeiss | ||||
| Still in use for instruction and public education | 30 cm (12") | 4.6 m (15 ft) | 1891 | |||||
| Still used for instruction and public outreach. | 30 cm (12") | 4.57 m (15 ft) | 1922 | Optics by John Brashear, mounting by Warner & Swasey. | ||||
| Pullman, Washington, USA | Used for instruction and pleasure | 30 cm (12") | 4.57 m (15 ft) | Assembled from older parts 1953[39] | ||||
| 30 cm (12")[40] | 4.5 m | 1955 | Largest and oldest Planetarium and Astronomical Observatory in Poland.[41] The 3rd largest in Eastern Europe (east of Germany), after Pulkovo Observatory in Saint Petersburg, Russia and Belgrade Observatory in Belgrade, Serbia | |||||
| Urbana, Illinois, USA | Used for instruction and pleasure | 30 cm (12") | 4.57 m (15 ft) | 1896 | by John Brashear, National Historic Landmark, still used for instruction | |||
| Still in use for education and public outreach | 28.956cm (11.4") | - | 1874 | by Hugo Schroeder, used to view transit of Venus that occurred on 9 December 1874 | ||||
| Mitchel Telescope Cincinnati Observatory | Cincinnati, Ohio, USA | - | 28 cm (11") | 1843 | Merz & Mahler
| |||
| Brashear Refractor Nicholas E. Wagman Observatory | Pittsburgh, Pennsylvania, USA | - | 28 cm (11") | 1910 | John Brashear, Amateur Astronomers Association of Pittsburgh[43] | |||
| - | 27 cm + 15.6 cm (10.6" + 6.1") | 350 cm + 294 cm | 1884 + 1890 | Double telescope by Repsold and Sons, optics by Steinheil | ||||
| - | 26.6 cm (10.5") | 399,5 cm | 1885 | |||||
| 26 cm (10.2") | 3 m | 1867 | ||||||
| Hume Cronyn Memorial Observatory | Western University London, Ontario, Canada | - | 25.4 cm (10") | 4.386 m (172") | 1940 | by Perkin-Elmer Corp. Glass from Chance Brothers. | ||
| Dundee, Scotland (1951) | 25 cm (10") | 1871 | by T. Cooke & Sons. Training telescope at St. Andrews 1938–1951 | |||||
| Paisley, Scotland (1898) | 25 cm (10") | 1898 | by Howard Grubb. Replaced 5" refractor by Thomas Cooke, installed in 1883. | |||||
| Blackett Observatory | Marlborough College Wiltshire, England | - | 25 cm (10") | 1860 | by Thomas Cooke. | - | ||
| 24 cm (9.6") | 1875 | An operational 1875 Merz telescope and one of the Oldest Observatories in South America, founded in 1873. | ||||||
| Fraunhofer Refractor, United States Naval Observatory (Foggy Bottom) | Foggy Bottom, D.C., USA | 24.4 cm (9.6") | 1844 [45] | |||||
| Moved 1913 to Munich, Germany | 24 cm (9.6") | 4 m (13.4′) | 1835 | Used to discover Neptune; in Deutsches Museum, München since 1913[46] | ||||
| Great Dorpat Refractor (Fraunhofer) Dorpat/Tartu Observatory (Old Building) | 24 cm (9.6") | 4 m (13.4′) | 1824 | "...the first modern, achromatic, refracting telescope."[47] [48] |