[daip] Header

[david russell]

Hi,
   I have a number of HST images from which I wish to produce a spectral index 
map. They all have the same pixel size and have been convolved. When I use COMB 
task as follows
   
AIPS 1: COMB: Task to combine in many ways two overlapping images
AIPS 1: Adverbs         Values            Comments
AIPS 1: ----------------------------------------------------------------
AIPS 1: USERID        0                    User ID. 0 => current user,
AIPS 1:                                      32000 => any user.
AIPS 1: INNAME     'NUV-C       '          First image name
AIPS 1: INCLASS    'CONVL '                First image class
AIPS 1: INSEQ         1                    First image seq. #
AIPS 1: INDISK        1                    First image disk drive #
AIPS 1: IN2NAME    '50CCD-C     '          Second image name
AIPS 1: IN2CLASS   'CONVL '                Second image class
AIPS 1: IN2SEQ        1                    Second image seq. #
AIPS 1: IN2DISK       0                    Second image disk drive #
AIPS 1: IN3NAME    '            '          First noise image name
AIPS 1: IN3CLASS   '      '                First noise image class
AIPS 1: IN3SEQ        0                    First noise image seq. #
AIPS 1: IN3DISK       0                    First noise image disk #
AIPS 1: IN4NAME    '            '          Second noise image name
AIPS 1: IN4CLASS   '      '                Second noise image class
AIPS 1: IN4SEQ        0                    Second noise image seq. #
AIPS 1: IN4DISK       0                    Second  noiseimage disk #
AIPS 1: DOALIGN       1                    Should images be coincident?
AIPS 1:                                    (See HELP.)
AIPS 1: OUTNAME    'SIM         '          Output image name
AIPS 1: OUTCLASS   '      '                Output image class
AIPS 1: OUTSEQ       -1                    Output image seq. #
AIPS 1: OUTDISK       1                    Output image disk drive #
AIPS 1: BLC        *all 0                  Bottom left corner
AIPS 1: TRC        *all 0                  Top right corner
AIPS 1: OPCODE     'SPIX'                  Algorithm type:
AIPS 1:                                    'SUM ','DIV ','SPIX','POLI',
AIPS 1:                                    'POLA','MULT','OPTD','CLIP'
AIPS 1:                                    'REAL','IMAG','MEAN','RM  '
AIPS 1:                                    'POLC'
AIPS 1: APARM         1        *rest 0     Parameters for algorithm:
AIPS 1:                                      (1) - (4) scale and offset
AIPS 1:                                      (8) > 0 => blank with 0.0
AIPS 1:                                      (9)  Map1 clip level
AIPS 1:                                      (10) Map2 clip level
AIPS 1:                                      see HELP COMB
AIPS 1: BPARM      *all 0                  Noise/control parameters:
AIPS 1:                                      (1)  Map1 noise level
AIPS 1:                                           -1 use 3rd image
AIPS 1:                                           0 ignore noise
AIPS 1:                                      (2)  Map2 noise level
AIPS 1:                                           -1 use 4th image
AIPS 1:                                           0 ignore noise
AIPS 1:                                      (3)  > 0 => output noise
AIPS 1:                                           in addition
AIPS 1:                                      (4)  < 0.5 => clip w inputs
AIPS 1:                                           > 1.5 => clip w S/N
AIPS 1:                                           else  => clip w noise
AIPS 1:                                      (5)  minimum ok S/N   or
AIPS 1:                                           maximum ok noise
AIPS 1:                                      (6)  max output noise
AIPS 1:                                           0 -> any
AIPS 1:                                      see HELP COMB

I get the following message

sophie> COMB 1: Task COMB   (release of 15OCT98) begins
sophie> COMB 1: Create SIM         .SPIX  .   1 (MA)  on disk  1  cno   25
sophie> COMB 1: PCOMBN: FREQUENCY AXIS NOT FOUND
sophie> COMB 1: Destroyed MA image file: catno=     25 disk= 1
sophie> COMB 1: Purports to die of UNNATURAL causes
sophie> COMB 1: sophie       15OCT98 TST: Cpu=       0.0  Real=       1

   How can I put the frequency information into the image headers to solve this 
problem? Also, how do I go about combining more than two images?
      Thanks
          David Russell
          drussell at stsci.edu