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       Michael A. Stecker 
 
       Places Index Other Astronomical Sites: 
          
          
          Keck Telescopes 
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        Keck I Telescope 
       
      
        
        
        I was fortunate to get a private tour of the Keck I telescope when  
      I visited Hawaii a few years ago. This is the largest telescope on the mountain with a 10 meter segmented primary mirror. 
        
        
        Made possible through grants totaling more than $140 million from the 
        W.M. Keck Foundation, the observatory is operated by the California 
        Institute of Technology, the University of California, and the National 
        Aeronautics and Space Administration (NASA), which joined the 
        partnership in October, 1996. The Keck I telescope began science 
        observations in May, 1993; Keck II 
      began in October, 1996. 
          
          The Keck I Telescope specifications: 
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          Primary mirror diameter: 10 meters (33 feet)  
         
        
          
          
          Mirror curvature:  f/1.75 hyperbolic mirror  
         
        
          
          
             Focal length: 17.5 meters (57.4 feet)    
           
         
        
          
          
          Primary mirror design:  Segment 
        
          
          
             Number of segments:  36  
        Segment shape: Hexagonal 
          
          
             Segment diameter: 1.8 meters (6 feet)
           
         
        
          
          
             Segment weight:  880 pounds 
        
          
          
             Segment material:  Zerodur (low-expansion glass-ceramic)
           
          
         
        
          
          
              Light-collecting area:  76 square meters (818 square feet) 
        
          
          
                 Total weight of glass:  14.4 metric tons (15.9 tons) 
        
          
          
             Telescope mount:  Altitude-Azimuth 
        
          
          
             Overall telescope height:  24.6 meters (80.7 feet)
           
         
        
          
          
             Total moving weight with mirrors:  270 metric tons (298 tons) 
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        The Dome 
       
      
        
        
        Dome height:  30.8 meters (101 feet)  
       
      
        
        
           Dome width:  37 meters (121.4 feet)
         
       
      
        
        
           Total moving weight:  
        635 metric tons (700 tons)   
      
        
        
        Keck II specifications: 
      
        
        
        The same as Keck I. 
      
      
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