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Bright (6.8U) possible nova in Del?

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Targets of opportunity
Bikeman
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Hi

With so many attention given to the field around Nova Del 2013, I was wondering whether people here have suggestions for scientifically interesting near-by targets of opportunity, especially for DSLR photometrists, but also for binocular observers. E.g. my exposures cover 20 deg x 15 deg so it would be a shame to ignore any interesting "bycatch".

Any suggestions, also for the time of decline of the nova when we will have to make deeper exposures ?

CS
HBE

Still 4.9ish
Bikeman
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Hi

I still see it at around 4.9 V, even tho some recent CCD observations claim 5.5 mag V 

 

CS

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Still 4.9ish
HQA
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I would not worry too much about the Vmag observations that are much fainter than the visual light curve; just report what you see.  There are a number of discrepant observations that will be checked in the next few days.  It is cloudy tonight at HQ, but I hope to start observing again tomorrow.

Arne

targets of opportunity
HQA
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Hi Heinz-Bernd,

If you go to VSX, and select a 10 degree radius circle with bright magnitude limits, you will find roughly 100 variables brighter than 8th magnitude within your image.  I don't think you need to pick and choose which ones to submit to the International Database, except that I'd probably just use the ones that have an AUID and a sequence.  That said, I do have a strong "like" for the cepheids: T Vul, SV Vul and S Sge.  You could also pick some of the NSV objects, or the stars with uncertain classification, and try to classify them.  This is a rich part of the galaxy, so lots of things that can be done with your images other than just measuring the nova!

As the nova gets fainter, the problem will be crowding with your wide-field DSLR image.  Any photometry of fainter variables will likely be contaminated by their neighbors.

Arne

Blending
Bikeman
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Hi Arne,

Many thanks for your suggestions. Some of the suspected variables look feasible with the accuracy I can get from the wide field DSLR shots, so trying to find out more about those would be interesting.

Yes, blending is a limiting factor, from my (catalog mag) vs (measured mag) curve, I see many affected stars starting at around ca 7.5 mag (all in all, SourceExtractor detects and analyses more than 4000 sources in the 20 x 15 deg^2 field)

E.g. out of the three Miras near maximum in Del suggested by Kevin Paxson in the LBV forum (S,T,X Del), two are too blended for my setup.

So when Nova Del 2013 gets near 7 mag, I'll probably switch from my 50mm lens to a 85 mm lens, and then finally to a 6" telescope.

Until then, I'd be happy to hear from others trying to work on suspected variables near the nova. It's not just more fun to do it in a team, it's also easier to produce convincing evidence.

CS
HB

Suspected variables near NoVa Del 2013?
FRF
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Since this field has been extensively covered by ASAS-3 in the past decade I wouldn't expect too many new variables in the field, but khow nows...

Anyway I follow this field using 300mm (zoom) telephoto lens, but last week I also made images usin the 75mm focus.

Btw NGC 6905 is also visible on my images.
A cropped version: http://www.flickr.com/photos/26731206@N05/9551330515/sizes/l/in/photostr...

The full FOV: http://www.flickr.com/photos/26731206@N05/9550663047/sizes/o/in/photostr...

Delphinus Nova Comps
msheald
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Hello! I obtained a time sequence of the nova last night in I,B, and V. Exposures ran 1 to 3 seconds wiht my 8 inch LX200 and SBIG 402.

    The comp and check stars were out of the field of view. Will any closer comps be available? Or are they too faint to serve that purpose? Best regards.

 

Mike

faint comp stars
FRF
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There are comp stars 79, 80, 90, 98, 100 on the D chart of the Nova (1 degrees FOV). Are they not good enough for you?

How big is your FOV? Since the nova is around 5.6 mag recently a small telescope or a DSLR camera with 1-8 degrees FOV must be good enough for photometry of Nova Del 2013.

not that many cstars to choose from
Bikeman
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Hi!

For that sensor/optics combination I would guess the FOV is even < 0.5 deg, right?


There are so few bright stars in that FOV that you can get personally acquainted to them: using SIMBAD I found only 10 stars at all which are brighter than ca 10.0 mag in a 0.5 deg radius, and only  five of them are brighter than ca 9 mag:

http://simbad.u-strasbg.fr/simbad/sim-coo?CooDefinedFrames=none&CooEpoch...

So the candidate pool for comp stars is quite limited.

DSLR photometry is one alternative. If you want to stay on the CCD track: for the epsilon Aurigae campaign it was demonstrated that you can get good results with a telephoto lens (with filter changer) mounted to a CCD, see Jeff Hopkins' page here: http://www.hposoft.com/EAur09/CCD/EAurCCD.html

CS
HBE

I think an 8 inch SCT is too
FRF
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I think an 8 inch SCT is too big for the nova recently.

Btw Arne made some CCD images with the BSM systems. Fainter AAVSO sequence will be available soon.

BSM photometry
HQA
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As Robert mentions, there is a preliminary calibration of this field at BVRI using BSM south that is available through Seqplot.  I use a subset of about 4 8th magnitude stars near the nova for my differential photometry.

Arne

8" SCT and Bright Star/Nova Photometry
msheald
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Thank you for the replies. My FOV is about 14x18 arcmin. I read the bright star photometry tutorial a while back. As I remember it, for bright star photometry, I would have to stack multiple images and/or defocus in order to use my system for bright stars such as this nova?

    However, from the comments, it appears that the nova might simply be too bright for my setup at present, regardless of how how massage the technique.

    I obtained about 300 images in each filter -B, V, and I - during the night's run. Once/if closer comps become availble, I thought that I would start by stacking them first in series of 10 to see if the SNR became acceptable, though I might have to increase that number depending on the SNR result.

    Thank you all for your guidance. Best regards.

 

Mike

Related anomalies closer to home
Jbeene
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Realizing that this question is slightly off the beaten path ....

My associates were performing an unrelated battery depletion/recharing experiment about the time (we learned later) that the Nova was first visible. This particular experiment had been said (anecdotally) to detect "gravity waves" in the past - but it can also be classified as fringe science, given the past lore and claims. Nevertheless there was a significant data event coincident with what was later determined to be this Nova. We could not correlate the two for many days.

That correlation could have been coincidental, and had it not happened on another device as well, at the exact same time - this inquiry would have gone no further. To make a long story shorter: a recurrence of the energy anomaly was seen last night and it happened on both the previous devices which had seen blip 10 days earlier.

Therefore, my question is this: is there an open repository of data on this Nova and its light emissions and/or - did anything significant happen last night? (Thursday night to Friday morning Aug 22/23)

Thanks in advance.

Spectroscopic Survey
FMT
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The amateur spectroscopic survey results are gathered in a data base

http://www.astrosurf.com/aras/Aras_DataBase/Novae/Nova-Del-2013.htm

More than 250 spectra at resolution from 600 to 15000 and a daily coverage by eShel Spectra. Observers around the world : France, Italy, Spain, Germany, UK,  US, Australy ...

See : http://www.astronomerstelegram.org/?read=5312

The P.I. is Steve Shore (University of Pisa)

The nova is always in the permitted lines phase. Balmer and Fe II lines respect to continuum increase day after day since 18-08-2013

The survey is currently focused on near UV/blue region and check possible CN lines 3883 and 4216

 

François Teyssier

A webpage shows the
FMT
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A webpage shows the spectroscopic evolution of Nova Del 2013 with ARAS spectra and comments, explanations about nova pnenomenon, lines formation ...  by Steve Shore (University of Pisa)

http://www.astrosurf.com/aras/novae/Nova2013Del.html

 

François Teyssier

On August 16, jeno mentioned
David Benn
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On August 16, jeno mentioned that:

The E-Nova collaboration has triggered radio observations, and once these are performed, they will provide a good first distance estimate. This is because the radio flux density is proportional to the size of the ejecta, modulo the distance, and we know the size of the ejecta from published velocities muliplied by the time since the start of the eruption.

Is there a distance result from this approach yet?

David

 

ATEL 5298
Bikeman
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Hi!


There is ATel#5298 from the following day with a limit on distance > 2kpc , with Jeno Sokoloski in the author list, so maybe that is related:

http://www.astronomerstelegram.org/?read=5298

Cheers

HB

 

 

Distance to V339 Del
jeno
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Hi David, and Bikeman.

In asking about the distance to V339 Del that one infers from radio observations, you raise a delicate issue.  You might notice that in ATel #5382, we report on the radio detection of V339 Del, but we do not say anything about a distance.  That is because something strange is going on.  The radio flux is quite low, suggesting that either: 1) the distance is surprisingly large for such a bright nova; 2) that there was a delay between the thermonuclear runaway that triggered the nova and the expulsion of material from the system; or 3) that the ejecta were initially too cold to produce radio emission.  We are waiting for additional data (at all wavelengths) to try to determine which of these options is correct. 

From optical spectroscopy, Steve Shore and collaborators suggest that the distance is 6 kpc (ATel #5409).

Cheers,

Jeno

At 6kpc distance, this would
Bikeman
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At 6kpc distance, this would place it quite a bit away from the galactic disk plane (about 1kpc?), or am I getting this wrong? 

Cheers

HB

Pre-nova magnitude
David Benn
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Fascinating re:  ATel #5382.

Another question I have is: where did the mag 16.9 minimum recorded on VSX come from? There was discussion earlier in this thread about pre-nova mags being captured on Perseid meteor images, for example. Was this 16.9 value taken from something like this or a previous "survey" plate or DSS or ...?

David

Please ignore my question
David Benn
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Please ignore my question about the 16.9 minimum magnitude.

Sara and Sebastian set me straight. I should have re-checked Sebastian's remark section on the V0339 Del VSX entry before asking.

It's a V magnitude from GSC2.3 with position from CMC14. This cone search result appears to be it.

David

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