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Old 23-10-2011, 02:23 PM
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Paddy (Patrick)
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Supernova 2011gv and some SMC objects 19 & 22/10/11

Well, some trying observing before moonrise on the 19th and between clouds on the 22nd. But I did get to observe Supernova 2011gv in IC4901 discovered by Ice in Space denizen Greg Bock

http://www.iceinspace.com.au/forum/s...t=82030&page=2

I also started obs on some of the fainter objects in the SMC and have discovered that my charts need some additions as some of the fainter Kron, Lindsay and Hodge/Wright clusters are well within the range of a 12-16" scope under dark skies. Chart upgrade on the way!

Thanks for reading. And thanks to Greg - a very exciting thing to observe.

Telescope 400mm f4.9 tri-dob reflector
Eyepieces 28mm UWAN, 17,13,9 mm Naglers, Paracorr
Navigation: Uranometria and my own charts of SMC from cloudsofmagellan.net.au

Object infromation from "Star Clusters" by Archinal and Hynes.

19/10/11

2135

Seeing fair, transparency poor

Kron 54 OC in SMC
06 06 47.8 –72 16 24
Dia 0.6 Vmag 12.65

175x 1/3 of the way from NGC 416 to NGC 371, this is a small but quite distinct glow with at least to clumps or resolvabe stars, the northernmost one being the brighter. There is a faint 1’ glow around the core which brightens with UHC filter.

Hodge/Wright 65 OC in SMC
01 11 58.5 –72 16 16

175x A soft E-W 2’x1’ glow to the east of a foreground star. There is a bright knot at the eastern pole. The object looks longer and wider with UHC filter but not brighter.

Kron 63 OC in SMC
01 10 47.9 –72 47 37

175x A very soft circular luminance perhaps 1’ or more across, but the edge is very hard to discern. The object appears a little patchy but has no marked core.

Lindsay 80 OC in SMC
01 07 28.5 –72 46 09

175x Very faint and difficult to pick – a process made more certain with UHC filter which show a 2’x1’ E-W glow around 2 stars.

22/10/11

2135

Seeing good, transparency good in the gaps between frequent clouds.

Supernova 2011gv in IC 4901 (GX in Pavo)

250X A viewing highlight indeed. Easy to find the galaxy as it is near a naked eye triangular asterism 1/3 of the way from Alpha Pavonis to the head of the peacock. To the preceding and slightly to the north of the faint galactic core is a tiny but distinct star. The galaxy itself is a faint glow slightly elongated roughly E-W 2 ½’ x1 ½’, the supernova visible within the western edge of the glow of the galaxy. There is a foreground star 3’ to the east of the galaxy. This observation before I’d even properly dark adapted. My plan to return later in the evening is foiled by cloud.

IC1611, IC 1612 and Kron 42 OC in SMC

This is a nice little group of 3 small clusters close to NGC 346

175X IC 1611 is closest to NGC 346 and is quite a bright not quite round cluster, uneven in brightness and with the impression of a core. Forms the apex of an isosceles triangle with two small stars to the east. Looks 2’x1’, longer E-W. IC 1612 is about 3’ to the SSW of IC 1611 and appears slightly smaller and rounder, but a magnitude fainter. Both have a somewhat grainy texture. 3’ further to the ESE is Kron 42, which looks about half as big as IC 1612 but significantly brighter and some clumps or stars can be resolved. Only IC 1611 responds convincingly to UHC filter.

Lindsay 66 OC in SMC
01 01 45.1 –72 33 51 Dia 0.7’ Vmag 11.7

175X This is a bright and distinctive little elongated E-W knot of stars and a tight pack of haze around it.

Clouds put an end to the session.
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Old 23-10-2011, 03:04 PM
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Paddy (Patrick)
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Chart 2 updated at Clouds of Magellan top include more objects -

http://www.cloudsofmagellan.net.au/page-3.htm
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Old 23-10-2011, 10:29 PM
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Excellent report Patrick, congrats on eyeballing the sn! Must download the chart update too. I've been accumulating a list of LMC globular clusters - hope to do some 'hunting' over summer.

Cheers -
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Old 24-10-2011, 04:18 PM
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Thanks for the report Paddy.
Not many people seem to report on star clusters, so look forward to your observations on them! I didn't know UHC filters could be used to help distant cluster obs. Learn something new everyday hey!

Good thing you got that sn in time before the clouds came in. You gave a nice description of where to find it, but my 10" in suburbia just isn't going to cut it, from what I've been reading lately. I am so jealous you and Ron have gotten to observe it!

Last edited by Suzy; 25-10-2011 at 02:11 AM. Reason: typo.
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Old 24-10-2011, 08:32 PM
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Thanks Suzy. I was indeed lucky to catch it on Saturday night as it doesn't look like there will be clear sky anytime soon.

The UHC filter I think is just showing how much nebulosity is associated with the clusters. The designations that I track down for them (ie cluster vs cluster with nebulosity) I suspect are not all that definitive. It is interesting how much difference it can make even with a very distant OC.
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Old 25-10-2011, 11:34 PM
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barx1963 (Malcolm)
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Paddy
Made it ouside to have a crack at the SN. Managed to get the galaxy with averted vision, IC 4901 is a faint little beggar! Unfortunately only 12", average transparency and light pollution all conspired to hide the supernova, though I thought I saw something, I think it was more wishful thinking than an obs.
Anyway although conditions were only fair, did spend a nice hour roaming the Fornax cluster and nabbed most of the Galaxies brighter than 12 I think!

Malcolm
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Old 26-10-2011, 08:51 AM
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Bad luck Malcolm. I reckon with better transparency and no LP you'd get it. Looks like a filed trip on the next clear night might be in order!
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Old 26-10-2011, 08:54 AM
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madbadgalaxyman (Robert)
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Malcolm,
I discussed this cute little Supernova with Astroron (Ron) in another thread, and we thought that the SN was probably visual magn. 14.8 or even somewhat fainter.
(but I haven't seen any accurate magn estimates in the science thread, as yet!)

Even under perfect conditions, a 12 inch would only reach a limit of about visual magnitude 15.4, according to Bradley Schaefer's (often cited) detailed investigation of telescopic limiting magnitude.

Given that the host galaxy is likely to be 1.75x to 2x as far away as the Virgo Cluster of galaxies, this explains why this SN is so faint.

(See also my theoretical discussion of the anticipated Apparent Magnitude and Colour of this supernova, in the science forum thread.)

Last edited by madbadgalaxyman; 26-10-2011 at 08:59 AM. Reason: more info
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Old 26-10-2011, 09:07 AM
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Hi Robert and Malcolm,the bright supernova website Here gives a mag of 14.1 it seemed fainter to me,but I haven't seen it since Monday and it is surposed to get brighter.
Malcolm,I think you will nead a really good sky to see this Supernova in your 12" as the galaxy is not very big and the Sn is faint, but fingers crossed that it gets a bit brighter.
Cheers
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Old 26-10-2011, 09:12 AM
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barx1963 (Malcolm)
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Yeah the search was more in hope than expectation
But I hadn't logged IC4901 before so a good excuse to have a crack. It must be a fairly large galaxy as the surface brightness was really low. Just a hint of a smudge.
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Old 26-10-2011, 10:06 AM
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madbadgalaxyman (Robert)
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Looks like that figure of 14.1 magn. might be from Joseph Brimacombe, whose image of the SN is at //www.rochesterastronomy.org/snimages

I have no idea what wavelength band this magnitude was measured in (this could make all the difference). It almost looked like it could be in the J-band, which is NIR (no use to visual observers)

Surely these SN blokes know that when we measure magns of supernovae, we have to "compare apples with apples"
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Old 26-10-2011, 10:47 AM
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Quote:
Originally Posted by madbadgalaxyman View Post
Looks like that figure of 14.1 magn. might be from Joseph Brimacombe, whose image of the SN is at //www.rochesterastronomy.org/snimages

I have no idea what wavelength band this magnitude was measured in (this could make all the difference). It almost looked like it could be in the J-band, which is NIR (no use to visual observers)

Surely these SN blokes know that when we measure magns of supernovae, we have to "compare apples with apples"
I concure with the statment above Robert
I have put a link to that site Here
Cheers
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Old 26-10-2011, 11:29 AM
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Paddy (Patrick)
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Malcolm, looking at the charts Robert put in the thread in the science section, we should still be able to have a crack at it at Snake Valley. It will be very interesting to do our usual observations in both our scopes.
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Old 26-10-2011, 11:34 AM
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If it is an infrared magnitude, then it is useless for comparison with the visually observed brightness of the SN.
Not that I would be too hard on anyone who erroneously compared two different types of magnitude....we are all amateurs, who love our hobby, but the limited amount of time we usually have available for astronomy means that we are usually 100% competent only in a narrow field within the vast science of astronomy.

[[ While I myself tend to be "technically competent" when it comes to magnitudes and galaxy structures, as I do read some scientific papers, it could still happen that I make a conceptual error...... simply because I have acquired what I know "in bits and pieces" instead of through a formal course of study. ]]

Last edited by madbadgalaxyman; 26-10-2011 at 11:34 AM. Reason: typo
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Old 26-10-2011, 01:11 PM
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barx1963 (Malcolm)
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Yes Paddy it would be fun to have a go at it at SV, but it may be sitting down in those trees, so we may have to be careful about where we put the scopes. When I tried last night it was 11-30 before it was clear enough to even bother trying and it was starting to sink into the glow on the SW horizon even then!

Malcolm
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Old 26-10-2011, 01:27 PM
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astroron (Ron)
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Greg Bock as just informed me on FB that Robert Evens was unable to see it in his 12" scope the night after of his discovery of the SN.
It will be interestingt if you manage to observe it on the weekend
Cheers
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Old 26-10-2011, 06:32 PM
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mozzie (Peter)
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hi guys
with the scope up and going again i was trying to see the s/n earlier in the week.. spending 3 odd hours at it with fair seeing but the occasional high cloud made it difficult. using my 26 and 17 nag the galaxy was easily seen and i'm positive i could see the s/n with glimpses and averted vision. but not 100 percent as there's several stars within the area.. i'll try again when the weather clears and back from astro camp.!!!!!!
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