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Old 23-10-2011, 08:29 PM
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astroron (Ron)
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Supernova 2011gv in IC 4901 (GX in Pavo)

23/10/11 09.28 UT 19.28 AEST 16" Newtonian
Eyepiece 6mm radian mag x 304.+17mm nagler with 2xbarlow 200xmag
Galaxy IC 4901. A grey elipse which brightens towards toward the center with a 12mag star due east which made the observing of the supernova a bit more difficult .
I first observed the supernova with a 6mm radian and was able to observe it with direct vision but was seen better with averted vision.I tried a 13mm nagler but was unable to see the SN
I used the combination of the 17mm nagler plus the 2xbarlow and the supernova was plainly seen .
Seeing was only about 6-7 out of 10 as it was not long after twilight.
Cheers

Last edited by astroron; 24-10-2011 at 10:26 AM.
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Old 23-10-2011, 10:30 PM
Rob_K
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Congratulations Ron, great to hear that you & Patrick have seen it!

Cheers -
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Old 24-10-2011, 10:11 AM
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Paddy (Patrick)
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Comparing your experience to mine, Ron, it certainly seems that this one like as much magnification as can be thrown at it.
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Old 24-10-2011, 10:24 AM
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Thanks Rob and Paddy,the night got better as the galaxy got lower and was able to hold the SN for a few seconds at a time even though the seeing only improved by a factor of 1 or so.
I hope to be able to follow the SN for the next few weeks to see if it brightens noticable.
At 90,000,000 LY or so it is amazing we can see it at all
I tried a 9mm+ 2x barlow but the seeing was just not upto it
Cheers
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Old 24-10-2011, 03:42 PM
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thanks, Ron, for the interesting observation.

It does seem, from your observation, that the SN at present is not really an easy object, even for a 16 inch.

I had always thought that a visual magnitude limit of about 15, for a ten inch telescope, was a reasonable figure which is in accord with reality , as per Bradley E. Schaefer's often cited investigation of telescopic magnitude limits in this paper: (1990), PASP, 102, 212

As a 16 inch has 2.5 times the light gathering power of a 10 inch, that ought to add another one magnitude to this limit (that is, a limiting magnitude of magn. 16), but Schaefer's detailed investigation finds that this is a little optimistic.....his figure 1 gives something closer to 15.75 magnitude as a realistic limit for a 16 inch.
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Old 24-10-2011, 04:05 PM
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Thanks Ron for your wonderful report using different eyepieces..
Guess I'll be giving this object a miss with my 10".
Bring on those naked eye supernovas (reflections of 1987A) where the whole sky is one big apperture ... oh to dream....


Robert:

I keep meaning to say this, so now I'm just going to...
Your posts are AWESOME reading- keep up the good work, it is appreciated. Your comments on galaxies are terrific contributions to visual observing and science forum threads.
Thank you.
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Old 24-10-2011, 04:13 PM
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Quote:
Originally Posted by madbadgalaxyman View Post
thanks, Ron, for the interesting observation.

It does seem, from your observation, that the SN at present is not really an easy object, even for a 16 inch.

I had always thought that a visual magnitude limit of about 15, for a ten inch telescope, was a reasonable figure which is in accord with reality , as per Bradley E. Schaefer's often cited investigation of telescopic magnitude limits in this paper: (1990), PASP, 102, 212

As a 16 inch has 2.5 times the light gathering power of a 10 inch, that ought to add another one magnitude to this limit (that is, a limiting magnitude of magn. 16), but Schaefer's detailed investigation finds that this is a little optimistic.....his figure 1 gives something closer to 15.75 magnitude as a realistic limit for a 16 inch.
Thanks Robert, yes I had to spend some time at times teasing it out,but other times it was quite plainly seen.
As you would be well aware that is for optimum conditions, such as age of person,clarety of sky,observers experience ect.
I would estimate the SN to be at about 14.8 mag or fainter.
I have observed supernova of 14.5 mag in my 20cm SCT in the past from my site here in Cambroon so your figure of 15.7 would be a fair one for the 40 cm.
I think I have observed one supernova at 15.1 mag in the past but that was on an exceptional night.
I hope the supernova gets a bit brighter but dont think it will be any better than Mag 13 or so.
Cheers
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Old 24-10-2011, 04:27 PM
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madbadgalaxyman (Robert)
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Quote:
Originally Posted by Suzy View Post
Guess I'll be giving this object a miss with my 10".
Bring on those naked eye supernovas (reflections of 1987A) where the whole sky is one big apperture .

Robert:

I keep meaning to say this, so now I'm just going to...
Your posts are AWESOME reading- keep up the good work, it is appreciated. Your comments on galaxies are terrific contributions to visual observing and science forum threads.
Thank you.

Why, thank you kindly, Suzy. The posts sometimes take some effort, especially the recent calcs that I did regarding the new SN.

Ron's estimate of the magnitude of the new Supernova (14.8 ) seems about right, and it is in accord with the preliminary measurement by Drescher.
However, I think we need some more measurements in order to confirm the magnitude of this SN!

As you can guess from Ron's comment about my post about magnitude limits of various telescopes, 15 is probably the limit for a 10 inch in dark and transparent skies.
(there are occasional reports of fainter magn. limits with a 10 inch telescope, but these are not significant for ordinary observers under ordinary good conditions)

Last edited by madbadgalaxyman; 24-10-2011 at 04:33 PM. Reason: correction
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Old 24-10-2011, 05:03 PM
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Thanks Robert.

And yes, I can see that many of your posts must be quite time consuming because you have to research and dig up all those figures and then type it all out. That's why the work you do is so hugelyappreciated and I wanted to make a point in telling you that.
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Old 24-10-2011, 05:47 PM
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astroron (Ron)
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Thank you Suzy, Yes I think you giving this one a miss is probably a good idea
I am sure down the track there will be a bright supernova that will be visible for the more popular smaller scopes and less than dark sky's
Another 1987a type Supernova would go down well wouldn't it?
No observing of the SN tonight as the weather is lousy

Cheers
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