List of largest optical refracting telescopes

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Image:Paris 1900 Refractor.jpg

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

The largest refractor ever constructed was French: an instrument sporting two interchangeable objective lenses (for visual and photographic use respectively) with 49.2 in (125 cm) diameter, focal length 187 ft (57 m). It was on display at the 1900 Paris Exposition. Due to the extreme focal length it was stationary. The telescope was aimed with the aid of a Foucault siderostat, a movable plane mirror of diameter 2 m (6.56 feet), mounted in a large cast-iron frame. The horizontal steel tube was 60 m (197 feet) long; for focusing, the telescope’s eyepiece/plate end could be shifted five feet on rails. With the lowest power - 500x - the field of view was 3 arc minutes. Due to the unfortunate location - right within the metropolis - and trouble with the siderostat the results were poor and not suited for scientific use. When the year-long exposition was over, its builders were unable to sell it. It was ultimately broken up for scrap; the lenses are still stored away at the Paris Observatory.

Observatory	Lens diameter	Focal length	Built	Comments
Paris 1900 Exposition (Paris, France)	1.25 m	57 m	1900	Fixed lens, total failure, scrapped.
Yerkes Observatory (Williams Bay, Wisconsin, USA)	1.02 m	19.4 m	1897
Swedish Solar Telescope (Roque de los Muchachos Observatory, La Palma)	1 m	15 m	2002	Adaptive optics corrected refractor telescope
Lick Observatory (Mount Hamilton (California), USA)	0.91 m	17.6 m	1888
Paris Observatory (Meudon, France)	0.83 m + 0.62 m	16.2 m	1891	Double telescope
Astrophysical Observatory Potsdam (Potsdam, Germany)	0.80 m + 0.50 m	12.0 m	1899	Double telescope
Côte d'Azur Observatory (Nice, France)	0.76 m	17.9 m	1887
Allegheny Observatory (Pittsburgh, Pennsylvania, USA)	0.76 m	14.1 m	1914
Royal Greenwich Observatory (Greenwich, London, England)	0.71 m	8.5 m	1894
Vienna Observatory (Vienna, Austria)	0.69 m	10.5 m	1878
Archenhold Observatory (Berlin, Germany)	0.68 m	21 m	1896
McCormick Observatory (Charlottesville, Virginia, USA)	0.67 m	9.9 m	1883
U.S. Naval Observatory (Washington, DC, USA)	0.66 m	9.9 m	1873
Royal Greenwich Observatory (Greenwich, London, England)	0.66 m	6.8 m	1897
Yale Southern Station (Johannesburg, South Africa)	0.66 m	10.8 m	1925	Yale-Columbia Refractor (moved to Mount Stromlo Observatory in 1952), same telescope as following entry
Mount Stromlo Observatory (Mount Stromlo, Australia)	0.66 m	10.8 m	1925	Yale-Columbia Refractor - Previously located in South Africa. Relocated to Australia in 1952. Destroyed by bush fire on January 18, 2003
Belgrade Observatory (Belgrade, Yugoslavia)	0.65 m	10.55 m		Same instrument as at the Berlin Observatory
Berlin Observatory (Potsdam, Germany)	0.65 m	10.12 m	1914	The Berlin Observatory moved in 1913 to Potsdam, Babelsberg

fr:Liste des plus grandes lunettes