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List of largest optical refracting telescopes
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List of largest optical refracting telescopes

Here is a list of the largest optical refracting telescopes sorted by lens diameter. The largest refractor ever constructed was French. It was on display at the 1900 Paris Exposition. Its lens was stationary, prefigured so as to sag into the correct shape. The telescope was aimed by by the aid of a Foucault sidérostat, which is a movable plane mirror of diameter 6.56 feet, mounted in a large cast-iron frame. The horizontal tube was 197 feet long and the objective had 4.1 feet in diameter. The results were poor. When the year-long exposition was over, its builders were unable to sell it. It was ultimately broken up for scrap.


Observatory Lens diameter Focal length Built Comments
Paris 1900 Exposition
(Paris, France)
1.25 m 57 m 1900 Fixed lens, total failure.
Yerkes Observatory
(Williams Bay, Wisconsin, USA)
1.02 m 19.4 m 1897  
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
Potsdam Observatory
(Potsdam, Germany)
0.80 m 12.0 m 1899  
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  
Berlin Observatory
(Berlin, Germany)
0.68 m 21 m 1896  
Johannesburg Observatory
(Johannesburg, South Africa)
0.67 m 10.9 m 1925  
McCormick Observatory
(Mount Jefferson, Virginia, USA)
0.67 m 9.9 m 1883  
Royal Greenwich Observatory
(Greenwich, London, England)
0.66 m 6.8 m 1897  
U.S. Naval Observatory
(Washington, DC, USA)
0.66 m 9.9 m 1873  
Mount Stromlo Observatory
(Mount Stromlo, Australia)
0.66 m 10.8 m 1925 Previously located in South-Africa. Relocated to Australia in 1952. Destroyed by bush fire on January 18, 2003