add

 ADD N1 N2 N3 N4 N5 -- Adds series of spectra together

 Parameters: 
     
  N1  -- Start slot of first group to add
  N2  -- End slot of first group to add
  N3  -- Start slot of group to add to first set
  N4  -- End slot of group to add to first set
  N5  -- First slot for results 

 If N3=N4 then the same spectrum will be added to all the spectra N1 to N2
 Header taken from N1 to N2 group.

 Selection criteria apply. A valid (non-masked) output pixel only results if
 BOTH input pixels are valid as well. Thus add is NOT the command to use to
 combine spectra of an object covering different wavelength ranges since only
 in the overlap region (if any) will you get any result. Use 'average' 
 instead.

This command belongs to the class: arithematic