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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Fri Jul 12, 2019 6:46 am
by Hamish Barker
New spectrum from last night. Had some issues with moonlight, mount and drive rate, and possibly haze, as the sub exposures seem a bit dimmer.

I think the calibration from my previous one was incorrect due to an automatic function in ISIS.

Does any know if there is a section on Bess database for nova spectra? (when I get my data quality sufficiently improved).

(updated the spectrum as it had a completely incorrect calibration)

qv19-20190711-2330utc.jpg
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Fri Jul 12, 2019 12:39 pm
by JJ Broussat
Hello,
Bess Database is only for Be type stars, not nova.
Best regards
Jean-Jacques Broussat

Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Fri Jul 12, 2019 2:25 pm
by Robin Leadbeater
Hi Hamish,

Francois sometimes opens a page in ARAS for specific objects if there is enough interest
http://www.astrosurf.com/aras/Aras_Data ... taBase.htm
but you can also submit calibrated spectra of any object to the BAA database if you like
https://britastro.org/specdb/
https://britastro.org/specdb/submission ... ements.htm

Cheers
Robin

Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Fri Jul 12, 2019 5:35 pm
by Francois Teyssier
Hi,


For novae, there's always a page opened in ARAS database since we have spectra and the PI is Steve Shore.

The page for Nova LMC2016
http://www.astrosurf.com/aras/Aras_DataBase/Novae/2019_NovaLMC2019.htm

The resolution should be at least 500 (e.g. ALPY600). Of course, in special cases, lower reolsution spectra could be accepted, for instance an identification spectrum.

Nice result with a SA, Hamish!
Note also the ATel based on Terry's observation: http://www.astronomerstelegram.org/?read=12917
Congratulations, Terry!

Fran├žois

Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Fri Jul 12, 2019 8:49 pm
by Hamish Barker
astronomers telegram website appears to be slow or down at the moment.

Right, I really need to finish my proper spectrograph!

Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Tue Jul 16, 2019 9:52 pm
by Hamish Barker
Another AT post, Terry has been onto it despite windy weather. It has been cloudy and wet here in Nelson so no more Star analyser observations since last thursday.

http://www.astronomerstelegram.org/?read=12938

Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Wed Jul 17, 2019 11:44 pm
by Hamish Barker
Clear again last night but full moon and the nova seems to have faded rapidly, now seems to be fainter than the adjacent mag 12.76 star GAIA 4685624430186064768.

So my S/N for last night is terrible, maybe 2-3. Anyway for what it's worth here is the stacked colour image (processed to show the spectra) and spectra taken from the binned 25x30s exposures.

The nova is right at the top of the frame. The GAIA start is immediately adjacent (below).

I wonder if Terry has managed to get another spectra?

qv19-2019-07-17-colour-processed.jpg


nova-asassn-qv19-20190717-1130utc-unfiltered-normalised.jpg
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Sun Jul 28, 2019 12:44 pm
by Hamish Barker
I got clear weather on three more dates (and clouds rolling in after 1 or two subs on another!).

22 Jul seems to be much less Hbeta, mainly Halpha

26 jul I used the club C14, but at the same dispersion as the other spectra. So it should be lower resolution due to the much longer focal length. But my other data were pretty poor images so maybe the better tracking of the c14 is giving better resolution anyway.

On 26 jul, the Halpha peak intensity is 3x what it was previously! I double checked that it wasn't a star accidentally sitting in the field of the slitless spectra, but it really is the star.

Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Tue Jul 30, 2019 8:15 am
by Terry Bohlsen
Hi All
Sorry I'm slow replying Hamish. Well done!
I have taken multiple spectra of this nova. It is getting pretty dim now at mag V=14.5
I don't think flux calibration would be easy with a SA200. I am using a slit spectrograph (LISA) and I can flux calibrate because I take simultaneous photometry through a V filter.
There has now been 2 telegrams thanks to Steve Shore!
Terry
asassn19qv_8composite.png

asassn-19qv_20190728.png
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Re: ASASSN-19qv: classical nova (11 mag) in the SMC

PostPosted: Tue Jul 30, 2019 10:49 am
by Robin Leadbeater
A nice set of spectra Terry!

Absolute flux calibration using the Star Analyser is an interesting subject. If you have a reference star in the same field you can do the spectroscopic equivalent of differential photometry and because it is slitless you don't need to worry about loss of flux at the slit. It is not straightforward (flat fielding in particular) and a rather niche technique but it can be useful for studying fast transients.
http://www.threehillsobservatory.co.uk/ ... tra_42.htm
For the BAAVSS/AAVSO meeting last year I took the results from that run and generated B and V mag data for comparison with conventional photometry. See the attached slides extracted from the full presentation (zipped pdf)

Cheers
Robin