[[process_fits]] reads the following keywords and sets the variable.

 * BITPIX - BITPIX -- This sets the flag in SPC for how many bits to treat the data.  Everything is eventually converted into unsigned integer.  For ORex, this is 16.  The camera is a 14-bit imager, but the SPOC will pad the leading bits to 0 to make it a simple unsigned 16-bit integer.  IF a LUT (look-up-table) is used, the SPOC will convert the 8-bit LUT into the standard 16-bit integers.

 * DATE_OBS - UTC0 -- The UTC time of the observation.  This is converted within SPC via SPICE into ET, setting both ET0 and ET.
 
 * EXPTIME - EXP -- The duration of the exposure.  It is used to calculate the midpoint of the exposure.  This is _____ used for OREx.

 * SCLK_STR -- CLK0 and CKLUSE - This is the spacecraft clock.  If this value is set in the FITS headers, it is the primary time used to calculate the midpoint of the exposure.

 * NAXIS1 NPX)
 * NAXIS2 (NLN)
 * CAMERAID (CAM)
 * MTR_POS (FLT)
 * LUT (LUT)

 * MCFWHTMP - NTX (1,1) -- MapCam temperature.  The final algorithm has not been decided yet.  However, the weighting of each temperature can be adjusted in the file [[DN2TEMP.TXT]].  This assumes a linear mixing of the four camera temperatures.
 * MCFWMTMP - NTX (1,2) 
 * MCLENTMP - NTX (1,3) 
 * MCROETMP - NTX (1,4)

 * SCFWHTMP - NTX (2,1) -- SamCam temperature.  The final algorithm has not been decided yet.  However, the weighting of each temperature can be adjusted in the file [[DN2TEMP.TXT]].  This assumes a linear mixing of the four camera temperatures.
 * SCFWMTMP - NTX (2,2)
 * SCLENTMP - NTX (2,3)
 * SCROETMP - NTX (2,4)

 * PCFWHTMP - NTX (3,1) -- PolyCam temperature.  The final algorithm has not been decided yet.  However, the weighting of each temperature can be adjusted in the file [[DN2TEMP.TXT]].  This assumes a linear mixing of the four camera temperatures.
 * PCFWMTMP - NTX (3,2) 
 * PCLENTMP - NTX (3,3) 
 * PCROETMP - NTX (3,4)

 * NCCHTEMP - NTX (4,0) and NTX (4,1) -- NavCam temperature
 * TCCHTEMP - NTX (5,0) and NTX (5,1) -- TAGCam temperature


 * SC_QA - QT(0) -- Quadterians.  OREx will write the spacecraft pointing information, as of when the image was taken, into the FITS header.  [[process_fits]] will output them in the file [[quaternions.txt]] in the format PICNM, QT(I), I=0,3
 * SC_QX - QT(1)
 * SC_QY - QT(2)
 * SC_QZ - QT(3)

 * BZERO - DDN and SIGNED -- FORTRAN reads all integers as signed.  If the data should be unsigned, then the DN values less than zero are converted into high-bit values

 * INSTRUME - INAME and NC -- This is the name of the instrument in human-readable form.  It sets the variable NC as follows:
    || INSTRUME || NC ||
    || MAP || 1 ||
    || SAM || 2 ||
    || POL || 3 ||
    || NCM || 4 ||
    || NFT || 5 ||
The order of this is important because the camera number is the reference that SPC uses for camera ID within the configuration files [[make_sumfiles.txt], [[DN2TEMP]], and [[FLATFIELD.TXT]]