PDS_VERSION_ID        = PDS3                                                  
RECORD_TYPE           = STREAM                                                
LABEL_REVISION_NOTE   = "                                                     
  2004-08-25  S.McLaughlin    Created                                         
  2005-02-10  S.McLaughlin    Resolved liens from Oct 2004 thermal-vac review 
  2006-05-18  DI:S.McLaughlin Resolved liens from Apr 2006 peer review        
  2006-10-02  DI:S.McLaughlin Corrected FOV characteristics                   
"                                                                             
                                                                              
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   = "                                                     
                                                                              
                                                                              
  Instrument Overview                                                         
  ===================                                                         
    The Medium Resolution Imager consisted of an f/17.5 Cassegrain telescope  
    followed by a filter wheel feeding directly onto a CCD for direct,        
    optical imaging.                                                          
                                                                              
    The MRI telescope was 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 contained two clear apertures and eight filters.  The    
    filters included duplicates of some of the medium-band filters in         
    the High Resolution Instrument, narrow-band filters that isolate OH,      
    CN, and C2 as well as the green and violet continuum.  These              
    narrow-band filters were designed to match the Hale-Bopp filter sets      
    used for ground-based programs since 1996.  The longest wavelength        
    filter was actually a long-pass filter that used the CCD response         
    to define the long-wavelength cutoff at about 960 nanometers.             
                                                                              
    The detector was a 1024 x 1024 split frame-transfer CCD with              
    21-micron-square pixels.  The electronics allowed 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, was about     
    5.2 milliseconds.  There are readout amplifiers in each of the four       
    quadrants.  Readout time for a full frame was 1.8 seconds.  Net pixel     
    scale was 10 microradians/pixel (2 arcseconds/pixel).                     
                                                                              
    The MRI instrument in full-frame 1024 x 1024 mode had the following       
    field-of-view characteristics:                                            
                                                                              
      Pixel Size     : 21 micrometers                                         
      Pixel FOV      : 10.0 microradians                                      
      Instrument FOV : 10.0 milliradians or 0.587 degrees                     
      Surface Scale  :    7 meters/pixel at 700 kilometers                    
                                                                              
    The three instruments on the flyby spacecraft, HRII, HRIV and             
    MRI, were mounted on a separate instrument platform together with         
    the star trackers.  The three instruments were nominally co-aligned.      
                                                                              
    For a detailed discussion of the instrument, see Hampton, et al.          
    (2005) [HAMPTONETAL2005].  This instrument overview was provided by       
    Dr. Michael A'Hearn, the principal investigator for the Deep Impact       
    mission.                                                                  
                                                                              
                                                                              
  Instrument Calibration                                                      
  ======================                                                      
    The MRI instrument was calibrated by using in-flight data as well as      
    pre-launch data taken during a thermal-vacuum test (TV4) performed in     
    2003.  The calibration of the MRI instrument was discussed in the         
    'Deep Impact Instrument Calibration' paper by Klaasen, et al. (2006)      
    [KLAASENETAL2006].                                                        
                                                                              
                                                                              
  Flight Performance                                                          
  ==================                                                          
    The MRI instrument generally performed as expected during flight.         
                                                                              
"                                                                             
                                                                              
  END_OBJECT          = INSTRUMENT_INFORMATION                                
                                                                              
  OBJECT              = INSTRUMENT_REFERENCE_INFO                             
    REFERENCE_KEY_ID  = "HAMPTONETAL2005"                                     
  END_OBJECT          = INSTRUMENT_REFERENCE_INFO                             
                                                                              
  OBJECT              = INSTRUMENT_REFERENCE_INFO                             
    REFERENCE_KEY_ID  = "KLAASENETAL2006"                                     
  END_OBJECT          = INSTRUMENT_REFERENCE_INFO                             
                                                                              
END_OBJECT            = INSTRUMENT                                            
END