2 September 2017 at 12:21 pm #573824
A confirmation of this PSN as a type 1a using the ALPY200 last night.Attached is my spectrum (black) overlaid on the best fit from GELATO
This is on the outskirts of ngc1067 currently at ~mag 15 and will probably brighten further over the next few days so could be a good target for a standard ALPY too.
Attachments:2 September 2017 at 1:57 pm #578508Paul LuckasParticipant
Another great SNe confirmation Robin. How many is this now ?
Paul2 September 2017 at 3:18 pm #578509
That’s 6 to date I think, though apart from taking a quick spectrum of the very bright sn2017eaw, I have not really been looking this year so this is the first in 2017. It looks like I have quite a bit more professional competition now though. For example ePESSTO now seems to be submitting half a dozen confirmations a night when it has telescope time.
I was planning to try for another one last night in ngc3172 (at2017gla) but it was so close to the pole (+89.1 deg Dec) that I was literally going round in circles trying to get the mount to point at it !
Robin3 September 2017 at 8:49 pm #578511Jeremy ShearsParticipant
This is excellent and valuable work that you are carrying out.
All the best,
Jeremy28 September 2017 at 8:04 am #578583Jack MartinParticipant
Congratulations I echo Jeremy’s comments.
Essex UK1 October 2017 at 11:54 am #578587
Just heard that a follow up by Swift was scheduled based on my classification 🙂
Robin1 October 2017 at 12:47 pm #578588Andrew SmithParticipant
Well done Robin you have got far to good at this! You also seem to get gaps in the cloud I don’t see.
Do you leave the Alpy on all the time or do you swap with your LHIRES III? Also do you have two cameras or do you have to swap one over?
Regards Andrew1 October 2017 at 1:22 pm #578589Paul LuckasParticipant
The SWIFT observation is a really nice addition to this, and confirms yet again the increasing importance of small telescope / fast response amateur spectroscopy. With your permission I’d like to use this example in an up and coming presentation that I’m giving on the subject at UWA.
Paul1 October 2017 at 5:16 pm #578586
This was discovered by Gaia on 17th at mag 17 and announced on 28th Sept but was much brighter last night (~mag 15 or perhaps brighter) last night when I took the spectrum and is still likely to be a few days from max so would be a good early evening standard ALPY candidate.
Robin1 October 2017 at 5:28 pm #578591
I have got quite adept at swapping between the LHIRES and ALPY now. They have separate cameras (Currently the ATK 314 and a stellacam on the LHIRES and ATK428 and ATK16ic-s on the ALPY) and are all wired up so I just have to physically swap them over. The one not in use sits in a box next to the scope. I have even got duplicate 200/600 modules for the ALPY now as well which can be changed over without needing readjustment other than aligning the camera angle. I tend to stick with one setup on any particular night though.
Sure, no problem. Let me know if you need any specific graphics, images etc
Robin2 October 2017 at 11:19 pm #578595
I follow your spectroscopy with interest, Robin. I’ve just imaged the SN – the stacked image is on my observing page. Very bright – guesstimate mag 14, when compared with Gaia 1564852608241033472. The SN is clearly visible on individual frames; I will keep lights and darks in case anyone wants them for photometry. Best wishes – David3 October 2017 at 12:56 am #578596
Nice image David. Photometry could be useful. Do you plan to submit it to David Bishop’s website? there are no measurements or images for this SNe there yet.
Only clouds and bands of rain on this side of the country tonight unfortunately.
I suspect it is close to maximum now and since it is a type 1a I had a go at estimating how bright it should get to at maximum.
According to NED http://ned.ipac.caltech.edu there are no redshift independent distance measurements for ngc4964 but based on the redshift the distance would be ~36Mpc. (Though for a relatively nearby target like this the errors could be high)
Using 36Mpc and an absolute V mag of -19.3 at maximum for type 1a SNe gives an apparent V mag at maximum of ~13.5 (not taking into account any extinction) so your mag 14 guestimate seems reasonable.
Robin3 October 2017 at 12:18 pm #578597
I’d be happy to submit my image and magnitude estimation (CCD, clear filter). I gather you have to go through VSnet to get your obs on the Rochester site, so I’ve sent a request to be added to the system. I’ve set a median stacking job going on my laptop during my lunchbreak – I can then use the Aperture Photometry Tool on that image to get a more accurate determination of the SN magnitude, using a couple of comparison stars.3 October 2017 at 1:13 pm #578598
I think VSnet takes the photometry data but you can submit an image with or without a magnitude directly to David Bishop,(at least that what I used to do !)
dbishopx at gmail.com
Robin4 October 2017 at 6:59 am #578604
Image now visible via Rochester SNimages site. Carried out photometry and checked it – magnitude came out brighter than I judged by eye, at 13.6. Would be good to image this target again. Perhaps Thu. David4 October 2017 at 12:23 pm #578605
That’s great David, topping the brightness charts currently. It is easily bright enough for the standard ALPY 600 now. Let’s hope the promised clear skies turn up on Thursday.
Robin6 October 2017 at 7:03 pm #578626
sn2017gxq was bright enough for the ALPY 600 last night despite the full moon. Here is the spectrum (black) overlaid on the best fit according to SNID
which predicts it is now just past maximum.
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