optsub

command list , class list , introduction .
 OPTSUB N1 N2 N3 N4 N5 FWHM SET -- Optimum subtraction of spectra

 OPTSUB subtracts constants times one set of spectra from another 
 set, adjusting the constants to minimise the residual scatter 
 between the spectra (excluding masked regions). The scatter is 
 measured by carrying out the subtraction and then computing the 
 Chi**2 between this and a smoothed version of itself. The routine 
 also reports a formal error and the coefficients A,B,C of 
 Chi**2 = A*F**2+B*F+C where F is the constant. It is assumed that 
 the noise is dominated by the spectra which will have the templates 
 subtracted from them.

  Parameters:
             N1   -- First of spectra to be subtracted from
             N2   -- Last of spectra to be subtracted from
             N3   -- First of spectra to subtract
             N4   -- Last of spectra to subtract
             N5   -- First slot for results
             FWHM -- FWHM of gaussian smoothing to be applied for Chi**2
             SET  -- Yes to mask bad regions from being used to compute
                     the optimum factor.

This command belongs to the classes: arithematic .


Tom Marsh, trm@astro.soton.ac.uk, Tue Oct 27 08:56:34 1998 .