List of largest optical refracting telescopes

$Paris 1900 exposition refractor$

Paris 1900 exposition refractor

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 sidÃÂÃÂ©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