
Elixir data products are modified by several programs, each of which
needs to make certain additions or changes to the headers.  this is a
summary of those programs and the relevant keywords.  These programs
may also add COMMENT and HISTORY fields, but these are ignored.

* basic master bias, flat, dark frames are created by 'imcombred'
  and adjusted by 'normalize'.

- 'imcombred' adds the following keywords:

IMCMB_DT= 'FLIPS ver 2.0 - Elixir by CFHT - Tue Aug 12 2003 -  9:09:32' / Date 
IMCMB_AL= 'SIGMA   '           / CCD or SIGMA clipping, Scaled or Weighted Diff
IMCMB_CA= 'MEAN    '           / Combining algorithm on final stack            
IMCMB_LS=                  3.5 / Lower threshold for clipping rejection        
IMCMB_HS=                  3.5 / Lower threshold for clipping rejection        
IMCMB_FT= 'MASTER_DETREND_SKYFLAT' / Stacked frame type                        
IMCMB_OP= '1DYMODEL_OVERSCAN + COMPUTED_MODE_RESCALING' / Input operations     
IMCMB_NI=                   16 / Number of input files                         
IMCMB_DA=                    T / Dual amplifier A,B (IMCMB_XX list format)     
IMCMB_IF= 'NAME BIAS_A MODE_A BIAS_B MODE_B' / Input file parameters           
IMCMB_nn= '712143f.fits[ccd00] 1287 3204 1232 3266' / Input file stats         

- 'normalize' adds the following keywords:

FLATSCAL=         1.0642668848 /                                               
TVSTART = '2000/1/1          ' / data validity start time
TVSTOP  = '2001/1/1          ' / data validity start time
ELCONF  = '03Bm01.flat.g.0   ' / Original Elixir config
EL_SYS  = '2.0               ' / Elixir System Version
EL_NRM  = '1.4               ' / Elixir Normalize Version
REL_DATE= '2003-09-30T15:59:33' / UTC Release Date

* scatter-corrected flats are created by 'fixscat'
- 'fixscat' adds the following keywords:

EL_SFILE= '02Bm05.scatter.g.36.00.fits' / Scattered Light Image Used
EL_SVER = 'B.0               ' / Scatter Correction Version

* scatter frames are created by 'mkscat'
- 'mkscat' adds the following keywords:

TVSTART = '2000/1/1          ' / data validity start time
TVSTOP  = '2001/1/1          ' / data validity start time
FILTER  = 'g                 ' / filter uxed for model
EL_SYS  = '2.0               ' / Elixir System Version
EL_SVER = 'B.0               ' / Scatter Correction Version
VERSION = 'B.0               ' / Scatter Correction Version

* master fringe frames are created by 'imcombred' and adjusted by
  'fr.smooth'

- imcombred adds the following keywords:

IMCMB_DT= 'FLIPS ver 2.1 - Elixir by CFHT - Tue Sep 16 2003 - 14:00:18' / Date 
IMCMB_AL= 'SIGMA   '           / CCD or SIGMA clipping, Scaled or Weighted Diff
IMCMB_CA= 'MEDIAN  '           / Combining algorithm on final stack            
IMCMB_LS=                  2.0 / Lower threshold for clipping rejection        
IMCMB_HS=                  2.0 / Lower threshold for clipping rejection        
IMCMB_FT= 'MASTER_DETREND_FRINGE' / Stacked frame type                         
IMCMB_OP= 'MODE_OFFSETING + FRINGE_RESCALING' / Input operations               
IMCMB_NI=                   31 / Number of input files                         
IMCMB_DA=                    F / Dual amplifier A,B (IMCMB_XX list format)     
IMCMB_IF= 'NAME BIAS MODE SCALING' / Input file parameters                     
IMCMB_00= '714505o00.fits 0 2582 0.441' / Input file stats                     

- fr.smooth adds the following keywords:

FRNG_C0 =         0.0000000000 / Fringe Cross Correlation linear fit term
FRNG_C1 =         0.7197280000 / Fringe Cross Correlation linear fit term
FRNG_SKY=      2882.0000000000 / Fringe Frame sky level
FRNG_RNG=       -80.0000000000 / Fringe Frame fringe strength
FRNG_REF= 'ccd13             ' / Fringe Cross Correlation reference chip
FRNG_PTS= '2003A.frpts.i.36.00.fits' / Fringe Point File
TVSTART = '2000/1/1          ' / data validity start time
TVSTOP  = '2001/1/1          ' / data validity stop time
EL_SYS  = '2.0               ' / Elixir System Version


* processed science images are created by 'imred', defringed with
  'imcombred', and keywords are updated with 'grab.keywords'

- imred adds the following keywords:

IMRED_DT= 'FLIPS ver 2.1 - Elixir by CFHT - Tue Sep 9 2003 - 12:29:37' / Date  
IMRED_IF= '703406o.fits[ccd00]' / Input file to process by imred               
IMRED_OF= '703406p00.fits'     / Output file resulting from the process by imre
IMRED_OP= 'MASK_BP + OVERSCAN + BIAS + DARK_CURRENT + FLAT-FIELD' / Operation(s
IMRED_MK= '2003A.mask.0.36.00.fits[ccd00]' / Mask of bad pixels (0/1) input fil
IMRED_OV= '1DYMODEL_OVERSCAN'  / Type of overscan level correction             
IMRED_BS= '03Am04n.bias.0.18.00.fits[ccd00]' / Bias frame input file           
IMRED_DK= '03Am04n.dark.300.18.00.fits[ccd00]' / Dark frame input file         
IMRED_DS=               1.0000 / Dark frame scaling factor                     
IMRED_DB=                    T / Dark frame first corrected by bias frame      
IMRED_FF= '03Am04n.flat.r.18.01.fits[ccd00]' / Flat-field frame input file     
IMRED_NF=                    T / Normalized flat-field                         
IMRED_SF=          1.009331465 / Output file dynamic stretching factor (BSCALe)

- imcombred adds the following keywords:

IMCMB_DT= 'FLIPS ver 2.1 - Elixir by CFHT - Tue Sep 9 2003 - 12:16:00' / Date  
IMCMB_AL= 'SD      '           / CCD or SIGMA clipping, Scaled or Weighted Diff
IMCMB_CA= 'SCALED_DIFFERENCE'  / Combining algorithm on final stack            
IMCMB_LS=                  2.0 / Lower threshold for clipping rejection        
IMCMB_HS=                  2.0 / Lower threshold for clipping rejection        
IMCMB_FT= 'DEFRINGE_SCIENCE'   / Stacked frame type                            
IMCMB_OP= 'MODE_OFFSETING + FRINGE_RESCALING' / Input operations               
IMCMB_NI=                    2 / Number of input files                         
IMCMB_DA=                    F / Dual amplifier A,B (IMCMB_XX list format)     
IMCMB_IF= 'NAME BIAS MODE SCALING' / Input file parameters                     
IMCMB_00= '703266p00.det 0 3808 1.000' / Input file stats                      
IMCMB_01= '03Am04n.fringe.i.18.00.fits[ccd00] 0 4062 1.108' / Input file stats 

- grab.keywords adds the following keywords:

NASTRO  =                   49 / number of stars used for astrometry           
CERROR  =         0.7334717934 / scatter in astrometry soln (arcsec)           
PHOT_C  =               25.715 / Nightly zero point - actual                   
PHOT_C0 =               25.743 / Nightly zero point - nominal                  
PHOT_CS =                0.017 / Nightly zero point - scatter                  
PHOT_NS =                    3 / Nightly zero point - N stars                  
PHOT_NM =                    3 / Nightly zero point - N images                 
PHOT_X  =                0.083 / Nightly zero point - color term               
PHOT_K  =                -0.04 / Nightly zero point - airmass term             
PHOT_C1 = 'r_SDSS            ' / Nightly zero point - color 1                  
PHOT_C2 = 'i_SDSS            ' / Nightly zero point - color 2                  
MAG_SAT =              13.8063 / approx saturation (mag)                       
MAG_LIM =              23.2063 / approx completeness limit (mag)               
DATEPROC= '2003-09-30T17:14:50' / Processing Date                                      
EL_SYS  = '2.0                ' / Elixir System Version                               
