IRAF echelle spectra at last

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Andrew Smith

Well after considerable procrastination on my part and with the help of the kind souls on the  SPEKTROSKOPIE  forum I have finally managed to extract 28 orders from my echelle spectrograms using IRAF. They are as yet un-calibrated in wavelength as I still need complete the mapping of the Th Ar lines to the orders ( more procrastination on my part).

I ran into one last obstacle when the spectral extraction crashed with an error “Polynomial separation too large” . Google only led to a very few links but I managed to hunt down a hidden parameter “polysep” and a reference to lowering it and by chance a hint to where it could be found.   Changing it fortunately fixed the problem… …phew.

The attached is the Th Ar spectrum from order 51 and matches that I got from Bass.

Regards Andrew