Probable SN in NGC 6946

Information about outbursts of eruptive stars, Be activity, ...
Paolo Berardi
Posts: 578
Joined: Thu Sep 29, 2011 10:51 pm

Re: Probable SN in NGC 6946

Post by Paolo Berardi »

Hi all, yesterday I also was able to observe the SN with Lhires III and 150 l/mm grating (R~600).

Image

Robin, I have the same response as yours from Gelato: IIP some days later.

Image

Image

From AAVSO lightcurve I saw that blue magnitude has undergone a temporary variation, I don'w know if it may reflect the blue continuum drop in Etienne and Fran spectra.

The minimum of P-Cygni h-alpha narrow absorption is close to 6280A in my spectrum. It should correspond to about 13000 Km/s for the ejecta velocity. It seems to me that also H-beta shows the same P-Cygni profile. Another line could be the broad He I 5876 (overlooking the narrow Na D line).

Paolo
Robin Leadbeater
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Re: Probable SN in NGC 6946

Post by Robin Leadbeater »

That is a very nice LHIRES spectrum Paolo. Worth the over 2 hours exposure !

A silly question. How do I display my graphs full size on the forum. Mine often only show part until they are clicked on

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Martin Dubs
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Joined: Fri Jan 06, 2012 9:16 pm
Location: Maienfeld, Switzerland

Re: Probable SN in NGC 6946

Post by Martin Dubs »

Robin,

the cutoff of the graphs depend on screen size in Pixels, scale of display of your browser and graph size. For my notebook with a reasonable display scale a graph width of about 600 to 800 pixels appears complete. Right click on an image in the forum and choose Image info to find out about the size (in Firefox). In ISIS you can adjust the size of the spectra on the Gnuplot page. Camera images you can downsize to a reasonable width with standard image view software (I use oldfashiond IrfanView). It is annoying sometimes if people post 16 MBit images full scale.

Regards, Martin
Robin Leadbeater
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Re: Probable SN in NGC 6946

Post by Robin Leadbeater »

Hi Martin,

None of my images are very large. To stop the images being cut off at the bottom I have to make them less than ~450 pixels high but there are many images in this thread much taller.

What do you see in my post here for example ?
http://www.spectro-aras.com/forum/viewt ... t=10#p8255

I see 3 out of the 4 images are truncated unless clicked on. They are smaller than many other images in this thread though. I see also that each image has information about it underneath which does not happen with Paolo's post here for example which has much larger images
http://www.spectro-aras.com/forum/viewt ... t=20#p8259

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
Martin Dubs
Posts: 141
Joined: Fri Jan 06, 2012 9:16 pm
Location: Maienfeld, Switzerland

Re: Probable SN in NGC 6946

Post by Martin Dubs »

Hi Robin,

in your post
viewtopic.php?f=5&t=1744&start=10#p8255
I see only the first image clipped in Firefox, three out of the four clipped in Edge browser.
In Paolos images, viewtopic.php?f=5&t=1744&start=20#p8259 no images clipped, the image info says e.g.
700px × 450px (Skaliert zu 581px × 374px)
I have no idea, why some images are scaled and others not.

Regards, Martin
umberto sollecchia
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Re: Probable SN in NGC 6946

Post by umberto sollecchia »

Félicitations Paolo, un excellent résultat.
Umberto
Robin Leadbeater
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Re: Probable SN in NGC 6946

Post by Robin Leadbeater »

Martin Dubs wrote: I have no idea, why some images are scaled and others not.
OK now I see the difference. Paolo (and Etienne's) images are held on their own sites and have links to them in their posts. These are not cropped. I (and Fran) have uploaded our images to the forum as attachments.

Cheers
Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
James Foster
Posts: 439
Joined: Sun Jan 24, 2016 7:14 am

Re: Probable SN in NGC 6946

Post by James Foster »

I've been imaging this SN candidate since Tuesday night (17May17), but I wasn't able to process my LISA spectra until I got a better focus btw the grating and 23 micron photometric slit.
The 17 & 18 May had degraded resolutions but I still was able to process them once I got a good IR curve on a nearby F4V star (HD157373) last night. Here is a 45 minute exposure on the SN candidate in NGC 6946 (Telluric Hg and O2 indicated):
Image



James
Last edited by James Foster on Sun May 21, 2017 12:51 am, edited 2 times in total.
James Foster
eShel2-Zwo ASI6200MM Pro
Lhires III (2400/1800/600 ln/mm Grat) Spectroscope
LISA IR/Visual Spectroscope (IR Configured)
Alpy 200/600 with Guide/Calibration modules and Photometric slit
Star Analyzer 200
Robin Leadbeater
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Re: Probable SN in NGC 6946

Post by Robin Leadbeater »

Hi James,

I presume the Hg lines (and fainter Na D emission and other narrow lines) are from residual light pollution sky lines incompletely removed by the background subtraction ?

Robin
LHIRES III #29 ATIK314 ALPY 600/200 ATIK428 Star Analyser 100/200 C11 EQ6
http://www.threehillsobservatory.co.uk
etienne bertrand
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Joined: Mon Aug 31, 2015 11:26 am

Re: Probable SN in NGC 6946

Post by etienne bertrand »

Paolo, Robin, James & Francisco congratulations for your goods spectra
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