PDS_VERSION_ID      = PDS3                                                    
LABEL_REVISION_NOTE = "                                                       
  13 January 2003, T.L. Farnham, Creation                                     
  27 January 2005, A.C. Raugh, corrected for delivery                         
  "                                                                           
OBJECT     = INSTRUMENT                                                       
  INSTRUMENT_ID      = "IGI"                                                  
  INSTRUMENT_HOST_ID = {"MCD27M","MCD21"}                                     
                                                                              
  OBJECT     = INSTRUMENT_INFORMATION                                         
    INSTRUMENT_NAME = "IMAGING GRISM INSTRUMENT"                              
    INSTRUMENT_TYPE = "CCD CAMERA"                                            
    INSTRUMENT_DESC ="                                                        
                                                                              
Instrument Overview                                                           
--------------------                                                          
                                                                              
The Imaging Grism Instrument (IGI) is basically a simple 5:1 focal            
reducer with a grism which can be moved into the collimated beam. It          
uses commercially-available optics that are coated for wavelengths            
greater than about 4000 Angstroms. There are two remotely movable             
stages one for the grism and one for the slit or a filter.  With the          
grism moved out of the beam, the instrument can be used in imaging            
mode.  The camera is a TeK 1024x1024 CCD, which produces a 7 arcmin           
vignetted field of view with 0.57 arcsec pixels on the 2.7-m                  
telescope.  On the 2.1-m the field of view is 6 arcmin, with 0.48             
arcsec pixels.                                                                
                                                                              
The IGI was designed for use on the 2.7-m Harlan J. Smith telescope at        
McDonald Observatory, but it can also be used on the McDonald 2.1-m           
Otto Struve Telescope.                                                        
                                                                              
Further details are given in the IGI description (IGIDESC.*) in the           
DOCUMENT directory.  This is a reproduction of the article Hill, G.J.,        
M.J. Wolf, J.R. Tufts, E.C. Smith, Volume Phase Holographic (VPH)             
Grisms for Optical and Infrared Spectrographs, in 'Specialized Optical        
Developments in Astronomy', Proceedings of the SPIE 4842, in                  
press. 2003. [HILLETAL2003].  Also included is the IGI operations             
manual (IGIMAN.ASC) that describes the use of the instrument."                
                                                                              
  END_OBJECT = INSTRUMENT_INFORMATION                                         
                                                                              
  OBJECT     = INSTRUMENT_REFERENCE_INFO                                      
    REFERENCE_KEY_ID = "HILLETAL2003"                                         
  END_OBJECT = INSTRUMENT_REFERENCE_INFO                                      
                                                                              
END_OBJECT = INSTRUMENT                                                       
                                                                              
END