PDS_VERSION_ID        = PDS3                                                  
RECORD_TYPE           = "STREAM"                                              
                                                                              
OBJECT                = TEXT                                                  
  PUBLICATION_DATE    = 2006-12-22                                            
  NOTE                = "CALIB directory contents"                            
END_OBJECT            = TEXT                                                  
END                                                                           
                                                                              
        CALIB Directory Contents                                              
                                                                              
This file describes the contents of the calibration directory.  The Deep      
Impact calibration pipeline used the files in this directory to reduce raw    
data.  The files were the result of the analysis of ground-based, thermal-    
vacuum and in-flight data for the instrument.  For more information           
about these files, the analysis, and the calibration pipeline, see the        
'Deep Impact Instrument Calibration' paper included on the Deep Impact        
documentation volume, DIDOC_0001.                                             
                                                                              
The calibration data were provided as FITS image files or ASCII tables.       
The following file naming convention was used:                                
                                                                              
  CCCCC/IIIIII-YYMMDD-V-M-FFF.{FIT,TAB}                                       
  |     |      |      | | |                                                   
  |     |      |      | | Optional filter number, temperature, or             
  |     |      |      | | place holder such as '0' or '999'                   
  |     |      |      | |                                                     
  |     |      |      | Instrument/Image mode (1 through 7) or a place        
  |     |      |      | holder such as '0' to indicate all modes              
  |     |      |      |                                                       
  |     |      |      File version (1, 2, etc.)                               
  |     |      |                                                              
  |     |      Date from which file is valid.  This is not the date the file  
  |     |      was created.  A value of '020601' indicates the file was       
  |     |      created from thermal-vacuum data.  A value of '000101' was     
  |     |      used a place holder.  It provides no useful information        
  |     |      but was required to keep the pipeline running.                 
  |     |                                                                     
  |     Instrument designation (e.g. HRIIR for HRII)                          
  |                                                                           
  Directory for the type of calibration file (e.g. FLAT)                      
                                                                              
Here is an example of a complete file name, FLAT/HRIIR_050112_1_7_0.FIT:      
                                                                              
    - FLAT     Flat field                                                     
    - HRIIR    HRII Instrument                                                
    - 050112   Effective date of 2005-07-01 (launch); this flat can be        
               applied to images acquired on 2005-01-12 UTC or later          
    - 1        Version 1 of the file file for the specified effective date    
    - 7        Instrument (image) mode 7                                      
    - 0        Placeholder (not a filter or temperature)                      
    - .FIT     FITS file                                                      
                                                                              
Calibration files are grouped into subdirectories by type:                    
                                                                              
  ABSCALIR                                                                    
  --------                                                                    
  This subdirectory contains one table of the absolute calibration            
  constants for each instrument (image) mode.  The first column               
  specifies the wavelength for the reading.  The second column                
  specifies the conversion factor for areas not under the                     
  anti-saturation filter.  The last column contains the conversion            
  factors for areas under the anti-saturation filter.  Two identical          
  files, one with a place holder of '000' and another with '999'              
  were created for the pipeline to allow existing processes to correctly      
  execute.                                                                    
                                                                              
  ADCLUT                                                                      
  ------                                                                      
  This subdirectory contains a lookup table for the correcting for            
  uneven bit weighting caused by the analog-to-digital conversion.            
  The single table applies to all instrument modes.  As of this archive,      
  the corrections had not been derived.  Therefore, the input pixel           
  values are the same as the output values to prevent the automated           
  calibration pipeline from changing the data.                                
                                                                              
  BADPIX                                                                      
  ------                                                                      
  This subdirectory contains maps that identify bad pixels for each           
  instrument mode.  These are master maps where a pixel is flagged bad        
  it was determined to be bad in each of the four in-flight science           
  calibrations.  Bad pixels are set to a value of 1.  Also, the               
  reference rows and columns around the edges of the array are set to 1.      
  Good pixels are set to 0.                                                   
                                                                              
  BIAS                                                                        
  ----                                                                        
  This subdirectory contains a dummy bias correction map for each instrument  
  mode.  All bias maps are set to zero to prevent the automated calibration   
  pipeline from changing data.                                                
                                                                              
  DARK                                                                        
  ----                                                                        
  This subdirectory contains dark frames for specific IR exposures.           
  The exposure ID to which this dark frame can be applied is specified        
  in the file name.  These darks were created by averaging the frames         
  within the specified exposure ID that were not on the target (i.e.,         
  background frames).                                                         
                                                                              
  DECOMPRS                                                                    
  --------                                                                    
  This subdirectory contains the four lossy lookup tables used to             
  decompress raw data.                                                        
                                                                              
  DRKMODEL                                                                    
  --------                                                                    
  This subdirectory contains master dark frames for each instrument           
  mode.                                                                       
                                                                              
  FLAT                                                                        
  ----                                                                        
  This subdirectory contains flat fields for each instrument mode.            
  Flat fields were derived from the linearity of each pixel.  Some            
  flats are dummies (all ones) as required by the calibration pipeline.       
                                                                              
  LINDN                                                                       
  -----                                                                       
  This subdirectory contains mode-specific maps of the four coefficients      
  used in a polynomial to linearize the raw data numbers.  Mode 5 must        
  use the mode 1 file.  Modes 6 and 7 must use the mode 4 file.               
                                                                              
  PSF                                                                         
  ---                                                                         
  This subdirectory contains a dummy point-spread function used by the        
  calibration pipeline when one is not available.  It is simply a             
  centered delta function to prevent any changes to the data.                 
                                                                              
  SPECMAP                                                                     
  -------                                                                     
  This subdirectory contains temperature-dependent, pixel-by-pixel,           
  spectral registration maps for each instrument mode.  The first             
  dimension provides the wavelength; the second provides the spectral         
  resolution (delta wavelength).  The temperature string in the file          
  names refers to the temperature of the IR spectrometer for which a          
  map is applicable.                                                          
                                                                              
  SUNSPEC                                                                     
  -------                                                                     
  This subdirectory contains two tables, based on different sources,          
  that provide the solar spectral irradiance at 1 AU for the given            
  wavelengths                                                                 
                                                                              
  XTALK                                                                       
  -----                                                                       
  This subdirectory contains tables that specify the amount of gain           
  from electronic cross talk that occurs between all possible                 
  combinations of the two quadrants of the IR array.  There is one            
  table for each instrument mode.  The cross-talk is across IR quadrants      
  is negligible, thus the table values are set to zero the automated          
  calibration pipeline from changing data.                                    
                                                                              
Icon  Name                                        Last modified      Size  Description
[DIR] Parent Directory - [DIR] abscalir/ 18-Sep-2006 15:37 - [DIR] adclut/ 19-Sep-2006 13:01 - [DIR] badpix/ 14-Nov-2006 11:48 - [DIR] bias/ 18-Sep-2006 16:05 - [DIR] dark/ 14-Nov-2006 18:06 - [DIR] decomprs/ 18-Sep-2006 16:15 - [DIR] drkmodel/ 19-Jul-2007 15:55 - [DIR] flat/ 20-Nov-2006 16:54 - [DIR] lindn/ 18-Sep-2006 16:58 - [DIR] psf/ 18-Sep-2006 16:44 - [DIR] specmap/ 18-Sep-2006 17:06 - [DIR] sunspec/ 18-Sep-2006 16:56 - [DIR] xtalk/ 19-Jul-2007 15:59 - [TXT] calinfo.txt 02-Jul-2007 15:07 12K
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