29 April 2014 at 1:28 am #573344
This supernova, discovered by Dave Grennan
is currently around mag 16.5 so a good challenging target for my ALPY spectrograph which I have modified specifically with the idea of obtaining low resolution spectra of supernovae for confirmation and identification. The initial results look quite promising. Here is the raw spectrum image of the galaxy core and supernova (below) superimposed on the night sky spectrum (110 minutes total exposure)
Further details and the fully processed spectrum are here on my website
This is certainly the faintest object I have ever recorded a spectrum of and I cannot offhand recall seeing anything fainter by other amateurs either. Further tuning should allow me to go a bit deeper still.
Attachments:29 April 2014 at 7:03 am #576548Nick JamesParticipant
Getting a spectrum with that dispersion of an object that faint is very impressive stuff. Do you know if there is a central database of amateur spectra anywhere?
Nick.29 April 2014 at 8:51 am #576549Gary PoynerParticipant
I would very much like to set up a database of amateur spectra of VS and link it to the VSS website. Roger and I have spoken briefly about this, and he seems to be ‘up for it’ too. I’m hopeful that we can discuss further at the VS meeting (York, June 21 see BAAVSS website) and move on from there. The AAVSO have been slow to move into this field, so I would like to see the VSS take the initiative.
Robin: Very impressive stuff at this faint limit. Many congratulations. I was singing your praises to Bradford AS last night, where I was speaking on Historical Novae. I’m pretty sure they will be contacting you with a view to a possible talk to their group sometime in the future.
Gary29 April 2014 at 1:25 pm #576550
There is currently no centralised international database but the object specific database BeSS for professional and amateur spectra of Be stars makes an excellent model for such a general database.
This is a professionally funded high quality system with moderation of submitted data and a mentoring service for amateur contributors run by pros and amateurs. There were thoughts to expand it but it would need funding. I have been talking with AAVSO for many years about this (including advising several of the various working parties there have been over the years) and the people behind BeSS have offered the complete system to AAVSO to use but they appear to want to go their own way against the advice of other experienced amateurs in this area and I have currently given up on them.
In the meantime the most complete source of amateur spectroscopic data is the ARAS organisation who have been archiving spectra submitted to them on a range of objects
(although unofficial, ARAS is where most serious amateur spectroscopists can be found and they are currently the main force driving up standards in this area)
I plan to talk more about how ARAS is functioning at the upcoming VSS meeting using Nova Del 2013 as an example
Robin29 April 2014 at 10:55 pm #576551Nick JamesParticipant
Thanks Robin. Both very useful sites. Nick.11 May 2014 at 6:38 pm #576555Roger PickardParticipant
I agree, most impressive.
As Gary mentions I’m very keen for the VSS to have some sort of database but I’ll probably be asking you to take the lead on this as it’s not an area where I’ve (yet) dabbled.
Cheers, Roger7 May 2015 at 7:31 pm #576859
I have been runnng with my “ALPY 200” low resolution faint object spectrograph configuration again over the past few weeks and have been able to work my way down about a mag fainter to around 17.5.
I recorded the spectra of these two supernovae (asassn-15fa and asassn_15fz) a few weeks after discovery so they have evolved significantly compared the original spectra taken soon after they were discovered. The match with spectra of supernovae at a similar age is still clear though.
The supernova contribution is already much lower than the sky background which is significantly limiting the signal/noise. I am not sure if more aperture or darker skies will be needed to go much lower, probably a combination of both.
Robin7 May 2015 at 9:13 pm #576860Jeremy ShearsParticipant
This is an amazing result, Robin. Having tuned your system to achieve such a faint LM, many objects will now be within your grasp.
Jeremy10 May 2015 at 10:29 am #576862Andy WilsonKeymaster
Stunning results. To obtain spectra of supernova down to mag 17.5 is really very impressive. Especially as you cannot directly see the target for guiding but have to work out the offset from a visible star.
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