log

 LOG N1 N2 N3 -- Takes natural log of spectra.

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


 Selection criteria apply. Negative pixels on the input spectrum are
 masked on output but otherwise left unchanged. For good pixels the
 new uncertainties become = error/flux where error is the orginal
 error and flux the original flux. This is the first order approx
 for small relative errors.

This command belongs to the classes: arithematic .