Thanks Paul, I have sent you the data I used in the example as requested by email and I look forward to what you discover. I looked at the Wiki on S-G and will look up D-W.
I am looking for something I can reliably program as I can have a hundred or more spectra per flare to process. The noise profile changes with observing conditions e.g.moon light so as simple and reliable as possible is good.
I used Matlab as I had it from a previous project not tried R but will look at it.