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 sid�rostat, 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 in Australia 
               in 1952
Destroyed by bush fire on January 18, 2003

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 in Australia in 1952 Destroyed by bush fire on January 18, 2003