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Re: Probable SN in NGC 6946

Posted: Thu May 18, 2017 6:43 pm
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

Re: Probable SN in NGC 6946

Posted: Thu May 18, 2017 7:23 pm
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

Re: Probable SN in NGC 6946

Posted: Thu May 18, 2017 7:55 pm
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

Re: Probable SN in NGC 6946

Posted: Thu May 18, 2017 10:20 pm
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

Re: Probable SN in NGC 6946

Posted: Fri May 19, 2017 8:50 am
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

Re: Probable SN in NGC 6946

Posted: Fri May 19, 2017 10:12 am
by umberto sollecchia
Félicitations Paolo, un excellent résultat.
Umberto

Re: Probable SN in NGC 6946

Posted: Fri May 19, 2017 2:21 pm
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

Re: Probable SN in NGC 6946

Posted: Fri May 19, 2017 11:11 pm
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

Re: Probable SN in NGC 6946

Posted: Sat May 20, 2017 3:10 pm
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

Re: Probable SN in NGC 6946

Posted: Sat May 20, 2017 4:14 pm
by etienne bertrand
Paolo, Robin, James & Francisco congratulations for your goods spectra