PDS_VERSION_ID        = PDS3                                                  
LABEL_REVISION_NOTE   = "                                                     
  2004-08-25  S.McLaughlin  Created                                           
  2005-02-10  S.McLaughlin  Resolved liens                                    
"                                                                             
                                                                              
OBJECT                = INSTRUMENT                                            
  INSTRUMENT_HOST_ID  = "DIF"                                                 
  INSTRUMENT_ID       = "MRI"                                                 
                                                                              
  OBJECT              = INSTRUMENT_INFORMATION                                
    INSTRUMENT_NAME   = "                                                     
        DEEP IMPACT MEDIUM RESOLUTION INSTRUMENT - VISIBLE CCD"               
    INSTRUMENT_TYPE   = "CCD CAMERA"                                          
    INSTRUMENT_DESC   = "                                                     
                                                                              
                                                                              
    The instrument overview was provided by Dr. Michael A'Hearn, the          
    principal investigator for the Deep Impact mission.  For a detailed       
    discussion of the instrument, see Hampton, et al. (2005)                  
    [HAMPTONETAL2005].                                                        
                                                                              
                                                                              
    Instrument Overview                                                       
    ===================                                                       
                                                                              
    The Medium Resolution Imager consists of an f/17.5 Cassegrain telescope   
    followed by a filter wheel feeding directly onto a CCD for direct,        
    optical imaging.                                                          
                                                                              
    The MRI telescope is a classical Cassegrain design with the following     
    parameters:                                                               
                                                                              
      Primary aperture        : 12.0 cm diameter, round                       
      Primary focal ratio     :  3.75                                         
      Secondary Obscuration   :  6.6 cm diameter, round                       
      Secondary magnification :  4.75x (net Cassegrain focal length 210 cm)   
      Back focal distance     : 30.0 cm                                       
                                                                              
    The filter wheel contains two clear apertures and 8 filters.  The         
    filters include duplicates of some of the medium-band filters in          
    the High Resolution Images plus filters aimed at isolating CN and C2      
    (the narrow-band filters are designed to match the Hale-Bopp filter       
    sets used for ground-based programs since 1996).  The shortest-wavelength 
    filter is broader and the longest wavelength filter is actually a         
    long-pass filter that uses the CCD response to define the long-           
    wavelength cutoff at about 960 nanometers.                                
                                                                              
    The visual detector is a 1024 x 1024 split frame-transfer CCD with        
    21-micron-square pixels.  The electronics allow readout of centered       
    sub-frames in multiples of 2, 64x64, 128x128, and so on, with or          
    without rows of overscan.  Transfer time, to move the two halves          
    of the image from the exposing area to the two shielded areas is          
    about 5.2 msec.  There are readout amplifiers in each of the four         
    quadrants.  Readout time for a full frame is 1.8 seconds.  Net            
    pixel scale is 10 microradians/pixel (2 arcseconds/pixel).  The           
    surface scale is 0.2 meters/pixels at 20 kilometers.                      
                                                                              
    The three instruments on the flyby spacecraft, HRII, HRIV and             
    MRI, are mounted on a separate instrument platform together with          
    the star trackers.  The three instruments are nominally co-aligned.       
                                                                              
"                                                                             
                                                                              
  END_OBJECT          = INSTRUMENT_INFORMATION                                
                                                                              
  OBJECT              = INSTRUMENT_REFERENCE_INFO                             
    REFERENCE_KEY_ID  = "HAMPTONETAL2005"                                     
  END_OBJECT          = INSTRUMENT_REFERENCE_INFO                             
                                                                              
END_OBJECT            = INSTRUMENT                                            
END