[daip] HST frequencies in Aips

[Eric Greisen]

david russell writes:
 > Hi,
 >     I've loaded a number of HST images into aips and wish to use the COMB task 
 > to produce a spectral index plot. I get the following message when I try to do 
 > this
 > 
 > sophie> COMB 1: Task COMB   (release of 31DEC99) begins
 > sophie> COMB 1: COMBIN: input maps coincident on reduced subimage only
 > sophie> COMB 1: Create 3C273 S     .SPIX  .   1 (MA)  on disk  1  cno    8
 > sophie> COMB 1: PCOMBN: FREQUENCY AXIS NOT FOUND
 > sophie> COMB 1: Destroyed MA image file: catno=      8 disk= 1
 > sophie> COMB 1: Purports to die of UNNATURAL causes
 > sophie> COMB 1: sophie       31DEC99 TST: Cpu=       0.1  Real=       0
 > 
 >     How do I include frquency information in the image headers? 
 >     

Spectral index requires the knowledge of frequency.  The aips verb
AXDEFINE lets you define a 1-point 'FREQ' axis.  The frequencies
should be Hz.

Eric Greisen