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Francois : Merci pour cette confirmation !

Paolo : Thank you so much for your comment !!
Very interesting to see the similar shape of line [OI] 6364 at high resolution !
Have you noticed any change in the position of the blue shifted peak for lines [OI] 6300 or 6364 over the last days ?

Clear skies to all !!

Christophe BOUSSIN

Hi Christophe, only the 6364 A line is included in my previous spectra (yesterday I rotate the grating, now I have also 6300 line!). There is a lot of noise for the oxygen line but I think I see only a gradual intensity increase from January 13. You can try with my spectra on ARAS DB. I just sent the last one (Jan 18) to François to be included in the database (if ok).




Changes in ~48 hours




The radial velocity of the lines in the Jan 18 spectrum.



Clear sky!
Paolo

Great result on such a faint star, Paolo. Congratulations.
Do tou think that it would be possible to get the OI 8448 line?
See tou!

I could try François, but the overall efficiency is low in those wavelengths. Weather forecast says next Tuesday could be the first useful night. I hope the nova brightness will not be decreased too much. Looking at a single 960 sec frame would have to make clear whether to continue or return to h-alpha (or change target!).

I'll let you know!

Paolo

Hello Paolo,
What CCD do you use ? Bin2x2 ?

Hi Etienne,

yes, binning 2x2. My camera is the SXVR-H694 model (Sony ICX694ALG sensor).

Paolo

Hi all,

Here is my spectra taken last night, the 19th, with an Alpy 600 and a Newton 250mm. Based on 10 pic of 600 seconds each.
Despite the strong intensity of the Halpha, we can't see the absorption at the top. Guess the limit of the low resolution (I obtained a resolution of 490).Or maybe I should have taken much more than 10 pictures when I see the nice spectra of Paolo, at the semae period. Below the Halpha in detail:
Cheers

Fred

Nice spectrum Frederic!

I think the lack of double-peaked h-alpha line is just a matter of resolving power. See the experiment below...

The Ne-Ar lamp spectrum with Lhires III and 1200 l/mm grating



By attempts, I applied a gaussian filter to this profile so that the FWHM of lamp lines was around 13 Angstrom to simulate a R=500 spectrum (this is an approximation).



Applying the same filtering to the nova spectrum I obtained an h-alpha profile very similar to yours.



The "bump" on the right is just a bit noticeable but, given the evolution of line between Jan 16 and 18 (see my previous post), maybe the red peak was even lower on the night of your obervation.

Clear sky!
Paolo

With my Alpy600 is see a double pics in all the H-Balmer line.

Frederic i think your Alpy is not at the top of resolution. you have bin2x2 or 1x1 ? What CCD ?

You can compare with spectra in ARAS BASE : http://www.astrosurf.com/aras/Aras_Data ... er2020.htm

I agree, the Frederic's Alpy 600 can do more, surely. Among the causes, undersampling but it could also be due to a slight defocusing of spectrum on the focal plane.

Paolo