Astroart Forum

Hmmm
Now working at R=4040....
Could have done with more exposure time....
The Hb region is the first processed...showing the now "standard P-Cyg" in both the Hb and Fe lines.
I've run a velocity graph based on the Hb (4861A) showing the larger absorption is still around the 1700Km/s
All spectra acquired and pre-processed with AstroArt, profiles prepared in BASS Project.
Feedback/ comments welcome. -------------
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Very good result Ken! Spectra L-200 works fine with more grooves per mm grating. Profile seems to have a good SNR (I don't see a lot of noise in this spectral interval).

Follows a comparison with an early stage Nova Del 2013 spectrum I took on 21 august 2013. There is similarity in h-beta and iron emission lines but the double absorption peak of P-Cygni profile that nova exhibits in your spectrum is very interesting... no doubt that Nova Centauri 2013 ejecta are more complex! Have a clear sky!
Paolo

Paolo,
Thanks for that!
Good comparison.
I have the choice of dropping back to the 600 l/mm (which is standard in the Spectra-L200) or push up to the 1800 l/mm
Hmmm decisions, decisions, decisions.....

Yes Ken, the choice of the grating is a great dilemma! I don't know if you have (like me) a different focus at UV/center/IR spectral intervals (due to internal doublet). In case, with low-res spectra it would be impossible to have everything correctly focused. On the other hand the use of 1800 l/mm involves a lot of work if you intend to acquire entire optical spectrum in each observing session, I think it may be perfect if you plan to observe systematically h-alpha line. Perhaps the best compromise is offered by the 600 l/mm grating. I used it (resolving power is about 2500 with Lhires) until the target reached mag V 11.5, adjusting the focus specifically for each spectral interval. Anyway I think that each observation, with any resolution, is a valuable element which helps to understand this interesting and rare (so bright) phenomenon!

Have great observations!
Paolo

Yes,
The Spectra-L200 has an Edmund achromatic doublet....same focusing issues, but I have the imaging camera mounted on a Borg #7315 helical focuser which can give me repeatability within 10 micron.
I use the Filly argon for calibration outside the Ha neon region.