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, although some of the largest refractors include a 21st century Solar telescope and, and the largest lens in refractor telescope, 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, with a 125 cm diameter lens. Larger 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	Image
Great Paris Exhibition Telescope of 1900	Paris 1900 Exposition	Dismantled 1900	125 cm (49.21")	57 m	1900	Fixed lens, total failure, scrapped. Aimed via a 2m reflecting siderostat
Yerkes Observatory	Williams Bay, Wisconsin, USA	-	102 cm (40″)	19.4 m (62′)	1897	Largest in current operation.
Swedish Solar Telescope, ORM	La Palma, Spain	-	100 cm (39.37")	15 m	2002	Single element non-achromatic objective combined with reflective Adaptive optics.
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
Potsdam Große Refraktor Astrophysical Observatory Potsdam	Potsdam, Deutsches Kaiserreich	Potsdam, Germany	80 cm + 50 cm (31.5"+29.5")	12.0 m	1899	Double telescope
William Thaw Telescope Allegheny Observatory	Pittsburgh, Pennsylvania, USA	-	76 cm (30″)	14.1 m	1914	Brashear made, photographic
Pulkovo observatory	Saint Petersburg, Russian Empire	Destroyed	76 cm (30″)		1885	Destroyed during WWII, only lens (made by Alvan Clark & Sons) survives.
Grand Lunette Nice Observatory	Nice, France	since 1988 Côte d'Azur Observatory	76 cm (30″)	17.9 m	1886	aka Lunette Biscoffscheim
28-inch Grubb Refractor Royal Greenwich Observatory	Greenwich, London, Great Britain	-	71 cm (28″)	8.5 m	1894
Grosse Refractor Vienna Observatory	Vienna, Austrian Empire	Vienna, Austria	69 cm (26 in)	10.5 m	1880	Largest refractor in 1880
Great Treptow Refractor Treptow Observatory	Berlin, Germany	-	68 cm (26.77")	21 m	1896	renamed Archenhold Observatory 1946
McCormick Observatory	Charlottesville, Virginia, USA	-	67 cm (26.37")	9.9 m	1883
U.S. Naval Observatory	Washington, DC, USA	-	66 cm (26")	9.9 m	1873
Royal Greenwich Observatory	Herstmonceux, Great Britain	-	66 cm (26")	6.8 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
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.
Pulkovo observatory	Saint Petersburg, Russia	-	65 cm (26″)	10.413 m	1930s	In Pulkovo since 1954.
Llano del Hato National Astronomical Observatory	Llano del Hato, Venezuela	-	65 cm (26 in)	10.5 m	1976
Belgrade Observatory	Belgrade, Kingdom of Serbia	Belgrade, Serbia	65 cm (26 in)	10.55 m		Zeiss made lens, same as at Berlin Observatory
Hida Observatory	Gifu, Japan	-	65 cm (26 in)	10.50 m	1972	Largest refractor of the East
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
Lowell Observatory	Arizona, USA	-	61 cm (24″)	6.7 m (22.6 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″)		1852	Problem with lens figuring
Radcliffe Double Refractor University of London Observatory	Oxford, UK	-	60/45 cm (23.6″/18")	7.0 m	1901	Obtained from the Radcliffe Observatory and installed in 1938
Zeiss Double Refractor Bosscha Observatory	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	-	58.4 cm (23″)	9.8 m (32 ft)	1881
Chamberlin Observatory	Colorado, USA	-	50 cm (20″)	8.5m (28 ft)	1891
Van Vleck Observatory	Connecticut, USA	-	50 cm (20″)	8.4m (27.5 ft)	1922
Chabot Observatory		Oakland, California, USA (2000)	50 cm (20″)	8.5m (28 ft)	1914	"Rachael" Warner & Swazey Company (Optics John A Brashear Company) Refurb in 2000 and moved to present location.
Imperial Observatory	Straßburg, German Empire	Strasbourg, France	48.5 cm (19.1″)	7 m (23 ft)	1880
18½-in Dearborn Observatory Refractor	Chicago, USA	-	47 cm (18.5″)		1862
Wilder Observatory	Amherst College, Amherst, MA, USA	-	46 cm (18″)	(25 ft)	1903	by Alvin Clark
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
Harvard Great Refractor Harvard College Observatory	Cambridge, Massachusetts, USA	-	38 cm (15″)		1847	largest telescope in America for 20 years
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
Urania Sternwarte (Zurich)	Zurich, Switzerland	-	30 cm (12″)	5.05 m	1907	by Fraunhofer and Zeiss
University of Illinois Observatory	Urbana, Illinois	-	30 cm (12″)		1896	by John Brashear
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
Great Dorpat Refractor (Fraunhofer) Dorpat/Tartu Observatory	Dorpat, Governorate of Estonia	Tartu, Estonia	24 cm (9.6″)	4 m (13.4′)	1824	"..the first modern, achromatic, refracting telescope."

See also

• List of largest optical reflecting telescopes
• List of largest optical telescopes in the 20th century

References

1. http://astro.uchicago.edu/vtour/40inch/
2. http://www.britannica.com/EBchecked/topic/653042/Yerkes-Observatory
3. solarphysics.kva.se The Swedish 1 m Solar Telescope "By using a lens of a single glass, excellent image quality is obtained through very narrow filters that isolate a single wavelength or color."
4. http://www.flamsteed.info/fasother6_files/page0001.htm
5. British university observatories, 1772-1939 By Roger Hutchins;page 252
6. http://www.flamsteed.info/fasother6_files/page0006.htm
7. Mount Stromlo Observatory brochure, page 12, The 26” Yale-Columbia Refractor, Australian National University, 2004, accessed 19 April 2008
8. http://www.aob.bg.ac.yu/instruments/index.html#Section1
9. http://www.craig-telescope.co.uk/
10. http://chestofbooks.com/crafts/scientific-american/Scientific-American-Reference-Book/The-Large-Refractors-Of-The-World.html
11. Scientific American Reference Book. A Manual for the Office, Household and Shop Author Albert A. Hopkins, A. Russell Bond Publisher Munn & Company Year 1905 Copyright 1904, Munn & Company
12. http://www.cfa.harvard.edu/hco/grref.html
13. http://amazing-space.stsci.edu/resources/explorations//groundup/lesson/scopes/harvard/index.php
14. http://www.wfs.be.schule.de/pages/hist/Bamberge.html
15. http://bdaugherty.tripod.com/astronomy/berlin.html#GALLE
16. http://adsabs.harvard.edu/abs/1967AmJPh..35..344W Fraunhofer and the Great Dorpat Refractor, Waaland, J. Robert, American Journal of Physics, Volume 35, Issue 4, pp. 344-350 (1967)
17. http://www.obs.ee/obs/instrumendid/fr.htm