BOSS Supernova 40

[Greg Bock (Greg Bock)]

Hi all,
another fantasic spectral confirmation for Peter's new discovery has now been offically released as SUPERNOVA 2012dy.

We were lucky enough to get the folks at the South African Astronomical Observatory, who report that low-dispersion spectra with the 10-m SALT telescope shows SN 2012dy to be a type-II supernova not long after outburst. In fact, given that Stu imaged the same galaxy 7 days before Peter, it must have been less than a week old.

Wow.....a 10m scope, how about that? This is amazing to have the 10m telescope at SALT do the confirmation for us. Apart from a variety of telescopes at Las Campanas, we have now had both Gemini telescopes, the NTT in chile, the Hubble Space Telescope, and the grand-daddy of them all, the 200" Hale Telescope on Mt Palomar take images and spectra of our discoveries...woweee


As it is a type II and is brightening, it will should become visible in larger amateur scopes and then fade slowly over the next few months, so there should be lots of opportunity to see it and image it.

An extract of the CBET is below:


SUPERNOVA 2012dy IN PGC 66545 = PSN J21185070-5738425
Greg Bock, Windaroo, Queensland, Australia, reports the discovery of a
supernova (red mag 15.6) by Peter Marples (Loganholme, Queensland) on an
unfiltered CCD image (limiting mag 18.5) taken on Aug. 3.53 UT using a 30-cm
Meade LX200R f/7 reflector (+ Starlight Xpress camera). The new object is
located at R.A. = 21h18m50s.70, Decl. = -57d38'42".5 (equinox 2000.0; measured
by Bock using the USNO-B and UCAC3 catalogues), which is 2".3 west and 17"
south of the nucleus of the galaxy ESO 145-4 = PGC 66545. Nothing is visible
at this position on Digitized Sky Survey red or infrared images (limiting mag
> 19). The variable was designated PSN J21185070-5738425 when it was posted
at the Central Bureau's TOCP webpage and is here designated SN 2012dy based
on the spectroscopic confirmation reported below. Additional magnitudes for
2012dy: 2012 July 27, [18.5 (Stuart Parker, Oxford, Canterbury, New Zealand;
30-s unfiltered red image; reported by Bock); Aug. 3.667, 16.6 (Joseph
Brimacombe, Cairns, Australia; infrared image, bandpass > 700 nm; position
end figures 50s.73, 42".4; image posted at the following website URL:
image posted at website URL
http://www.flickr.com/photos/43846774@N02/7713955784/).


------------------------------------------

Good luck if you want to check it out for yourself!

[Greg Bock (Greg Bock)]

Also, Pete just pointed out to me that BOSS have discovered 19 supernovae to date since the end of last years Astrofest with 2 weeks to go to the end of this years Astrofest (starting with 2011ei)!

Stu has 15, Pete and I are at 2 each.
The previous year was 7!
This is remarkable. How good is that for a team effort!

Now we just have to do better than that over the next 12 months to the 2013 Astrofest...

[DavidTrap (David)]

Great to hear the pros are following up your data!

I added 10x5min light frames to the end of an imaging run last night. When had a quick look this morning before work, I couldn't even find the galaxy - might have to check and see if I entered the coordinates correctly. (On another note, absolutely loving CCD Commander - imaging while I sleep!!!)

DT

[DavidTrap (David)]

Found it.

Was right in the middle of the frame, so nothing wrong with my pointing - just very small and faint.

Lots of stretching to drag out this detail, but the star I've pointed out lines up with Joe Brimacombe's shot. (My light gathering capacity is about 1/15th of his rig).

10x5min subs, bin 1x1, Tak FS-102, QSI583

DT

[Greg Bock (Greg Bock)]

Nive shot Dave, well done..lotsa stretching for faint fuzzies like this are the only way to go to get the detail.

[PeterM]

Excellent David,
Now print it out and I will sign it - for a fee hehehe
Seriously that is great work.

[DavidTrap (David)]

Thanks Gents,

I added some 2x2 subs to my list last night, but only 2 of 10 completed - from the looks of things a bit of high cloud has arrived this morning.

The galaxy & SN are much more easily visible on this image.

DT

[PeterM]

David send it for inclusion to Dave Bishops supernova page
http://www.rochesterastronomy.org/snimages/
through his email at
dbishop@vhdl.org

[DavidTrap (David)]

Ok,

Finally found the time to play with the photometry feature of Maxim.

Using some reference star magnitudes from SkyX, I measured the magnitude of the object at 16.4. Now bear in mind this is the first time I have fiddled with photometry, so I could be giving you figures for "Playmate of the Month".

I performed the measurements on ten calibrated and stacked images. I used 2 reference stars and 1 check star. The magnitude of the check star was within 0.15 of the published value. My camera is an ABG sensor, but I deliberately picked stars with <50% saturation of the pixels. I varied the annulus & gap widths to try and avoid sampling the background galaxy, but there was no dramatic change in the magnitude of the object.

Any suggestions as to why my measured value is over a magnitude lower than what you have measured??

Cheers,

DT

[Suzy]

Originally Posted by PeterM

Excellent David,
Now print it out and I will sign it - for a fee hehehe
Seriously that is great work.

I think I helped give him that big head when I visited the shop aaages ago and asked him who the supernova discoverer is that worked there that was in AS&T magazine. I didn't know it was him. Forgive me. I'm surprised he didn't ask me if I wanted my newly purchased scope signed.
Btw, I want to re-read that article again, do you remember which issue it was? No, I don't want the magazine signed.
Aaaah sorry Peter, couldn't resist.. all too funny, you walked right into that one.

Many congratulations Peter on your 5th SN discovery!
The speed at which you guys are nabbing these are getting higher and higher! Just think what Stu could do with a third observatory! But I guess that would mean zero sleep.
What an amazing 12 months it's been for the BOSS team, so incredibly proud of you guys and when you talk about NASA's equipment & Hubble even (!) partaking in these obs... WoW!!!

[madbadgalaxyman (Robert)]

Originally Posted by DavidTrap

Ok,
Finally found the time to play with the photometry feature of Maxim.
Using some reference star magnitudes from SkyX, I measured the magnitude of the object at 16.4.

Any suggestions as to why my measured value is over a magnitude lower than what you have measured??

David,

Well first of all, what kind of magnitude is it that you were measuring......
B ? (approximates a blue-sensitive photographic plate)
V ?? (approximately yellow-green light)
R ??
I ?? (about 800nm)

These above are Johnson-Morgan-Cousins magnitudes that are in common use, and often plotted in star atlas databases.

Each type of magnitude corresponds to a specific bandpass (filter) with a specific transmission curve.

Other magnitude systems are also possible, for instance the Sloan Digital Sky Survey magnitudes
( u , g , r , i , z)

It is possible to interconvert one type of magnitude to another, and I used to have a crib sheet at home that allowed me to do this with the greatest of ease......though I am "away from home at present," so I would have to look up the conversion elsewhere.

The conversion can also depend on the colour of the object, for instance a Very Red object has B-V = 1 to 1.3 while a Very Blue object has B-V of 0.5 or less.

Oh, and one more thing (added in edit):
Sky transparency and the altitude of the object can also make a big difference to its measured magnitude.

[PeterM]

"Btw, I want to re-read that article again, do you remember which issue it was? No, I don't want the magazine signed.
Aaaah sorry Peter, couldn't resist.. all too funny, you walked right into that one.

Many congratulations Peter on your 5th SN discovery!
The speed at which you guys are nabbing these are getting higher and higher! Just think what Stu could do with a third observatory! But I guess that would mean zero sleep.
What an amazing 12 months it's been for the BOSS team, so incredibly proud of you guys and when you talk about NASA's equipment & Hubble even (!) partaking in these obs... WoW!!![/QUOTE]"

Thanks so very much Suzy for your kind words.

The article you refer to in AS&T was April 2010 pages 46-48 and err umm happy to sign it err umm for a fee, see my agent Ron Gibson C/-Sirius Optics hehe. Actually Greg Bryant has given us permission to scan the article and put it on our website www.bosssupernova.com onya Greg!

In all seriousness though I take my hat off (even though I don't wear one) to you Suzy and many others like you here on IIS who answer beginners questions so very well and with much passion and relevant information - as I have often said you do amateur astronomy a great service that so often goes unrewarded unlike discoveries and pretty pictures - I therefore dedicate SN2012dy to Suzy and all those who do great service to amateur astronomy for no fee.

Stu a 3rd observatory is a done deal - well err umm he has that set up and will be doing 10,000 images per month until he goes bonkers from blinking. Ok we are helping him out on that but it's raining non stop in Oxford NZ and he is going bonkers anyways.

Thanks again and keep up the great work!

[DavidTrap (David)]

Originally Posted by madbadgalaxyman

David,

Well first of all, what kind of magnitude is it that you were measuring......
B ? (approximates a blue-sensitive photographic plate)
V ?? (approximately yellow-green light)
R ??
I ?? (about 800nm)

These above are Johnson-Morgan-Cousins magnitudes that are in common use, and often plotted in star atlas databases.

Each type of magnitude corresponds to a specific bandpass (filter) with a specific transmission curve.

Other magnitude systems are also possible, for instance the Sloan Digital Sky Survey magnitudes
( u , g , r , i , z)

It is possible to interconvert one type of magnitude to another, and I used to have a crib sheet at home that allowed me to do this with the greatest of ease......though I am "away from home at present," so I would have to look up the conversion elsewhere.

The conversion can also depend on the colour of the object, for instance a Very Red object has B-V = 1 to 1.3 while a Very Blue object has B-V of 0.5 or less.

Oh, and one more thing (added in edit):
Sky transparency and the altitude of the object can also make a big difference to its measured magnitude.

Time for confessions - these frames were taken through an Astrodon Luminance Filter. I assumed (and assume is the mother of all stuff ups) that a generic magnitude value in the catalogue would appropriate for "unfiltered" photometry.

I also thought transparency / altitude mainly affected all sky photometry, not relative photometry??

Young grasshopper has much to learn! Thanks for the explanation.

DT

[rogerg (Roger)]

Hey all,

I don't know much about estimating magnitudes either, but have found my best success is with Astrometrica. I have never had what I've considered to be good results from CCDSoft. Presumably just a case of knowing how to use CCDSoft.

Here (attached) is my analysis from Astrometrica. I was very happy it easily matched the field for once! Miracle. Normally I need to fiddle lots.

I have had phtogoraphs of the galaxy scheduled in to my nightly runs, only have 3 nights of images of it, but oh well. Raining.

Roger.

[Jen]

Congrats guys the time and effort u put into these projects must be so rewarding when discoveries like this are found well done

[Suzy]

Originally Posted by PeterM

In all seriousness though I take my hat off (even though I don't wear one) to you Suzy and many others like you here on IIS who answer beginners questions so very well and with much passion and relevant information - as I have often said you do amateur astronomy a great service that so often goes unrewarded unlike discoveries and pretty pictures - I therefore dedicate SN2012dy to Suzy and all those who do great service to amateur astronomy for no fee.

OMG! Thank you! Thank you! Thank you!

I'm truly honored that you have done this. You have a big heart Peter!
I'll get a print of the galaxy with the sn and pop into a frame along with your beautiful comment.
This means so much!

[mozzie (Peter)]

i'm going to have another try tonight pete to see if i can get a glimpse,going to try in early hours at it's darkest...

[DavidTrap (David)]

I was going to have a look for your SN in Peter's 30inch dob out at Leyburn, but unfortunately the galaxy wasn't in the Argo Navis...

Hope you have some success Mozzie.

DT

[mozzie (Peter)]

i was definately on the galaxy tonight under nice seeing and dark skies..with my 14"sct using sky safari to control.galaxy was faint with no visable core and ranging in mag 101x up to around 300x i thought i was able to see a small very faint very averted vision speck over an hour of observing it was not 100 percent positive but hay it's been a nice try maybe the 14" is just not quiet enough....
i use sky safari+ when manually moving my 16" dob with setting circles and wonder weather the gal is just to faint for a positive position and sight...

i thought the 14" with a focal length 3556mm may have helped me...bugger

pete could you try to find one a little more brighter for use visual people

[CometGuy]

You guys should get some grant money in recognition for your contributions! Would be nice to have to be able to confirm your own supernova for example, what size scope do you need for that - a 20" ?

Terry