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hiro
Pooh-Bah


Reged: 07/17/07

Loc: Tokyo
Re: C/2012 S1 ISON new [Re: Tonk]
      #6103967 - 09/27/13 11:22 AM

I tried imaging of the comet again under moon light September 26, 2013UTC. The comet was already in Leo, and the green halo was present there again.



Data and original are here.
http://www.flickr.com/photos/hiroc/9966413925/


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CygnuS
sage


Reged: 07/11/11

Loc: The Great Rift
Re: C/2012 S1 ISON new [Re: hiro]
      #6104627 - 09/27/13 05:25 PM

Nice job hiro! Thanks for sharing it.
(Could somebody tell me why the word "job" turned orange and was underlined twice after I sent my post?)

Edited by CygnuS (09/27/13 05:28 PM)


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hiro
Pooh-Bah


Reged: 07/17/07

Loc: Tokyo
Re: C/2012 S1 ISON new [Re: CygnuS]
      #6105041 - 09/27/13 10:26 PM

Thanks CygnuS in The Great Rift.

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jshalpha
professor emeritus


Reged: 04/30/05

Loc: SF Bay Area
Re: C/2012 S1 ISON new [Re: hiro]
      #6106770 - 09/28/13 11:36 PM

Inspired by the images here I resumed my efforts too. Here is my latest from this morning (Sept 28).

http://www.pbase.com/jshuder/image/152610426/large

Jim S.


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hiro
Pooh-Bah


Reged: 07/17/07

Loc: Tokyo
Re: C/2012 S1 ISON new [Re: jshalpha]
      #6106812 - 09/29/13 12:29 AM

Thanks Jim for the presentation of the clean image.

I have a question. Did you use red continuum (RC) filter or NIR-blocked L filter?


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CygnuS
sage


Reged: 07/11/11

Loc: The Great Rift
Re: C/2012 S1 ISON new [Re: hiro]
      #6107295 - 09/29/13 11:40 AM

Look great Jim!

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jshalpha
professor emeritus


Reged: 04/30/05

Loc: SF Bay Area
Re: C/2012 S1 ISON new [Re: hiro]
      #6107329 - 09/29/13 11:55 AM

Thanks Hiro. I used a Baader L filter which blocks IR starting at 700nm. I wanted to do a sequence of RGB, but my sky conditions are pretty bad this low to the horizon. I think its a good suggestion to just try the red channel, but the exposures would have to be longer. I shot this at 2350mm fl and ISON is traveling pretty fast. For my setup, ISON is moving about 2.4 pixels per minute (1.4 arc seconds per minute). A trial two minute exposure showed some smearing.
The next time I try this I will use a shorter fl scope since the comet is moving fast and its getter bigger.

Jim S.

Edited by jshalpha (09/29/13 12:05 PM)


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canukLX90
professor emeritus


Reged: 12/25/08

Loc: B.C. Canada
Re: C/2012 S1 ISON new [Re: jshalpha]
      #6107577 - 09/29/13 01:57 PM

A very nice image of the comet. Thanks for posting for
us fuzz ball chasers to enjoy!

PJ


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Dave Mitsky
Postmaster
*****

Reged: 04/08/02

Loc: PA, USA, Planet Earth
Re: C/2012 S1 ISON new [Re: canukLX90]
      #6115176 - 10/03/13 01:21 PM

There is further discouraging news about Comet ISON at http://astronomia.udea.edu.co/cometspage/

Dave Mitsky


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John Wunderlin
Vendor - Spike-a Focusing Mask
*****

Reged: 10/01/04

Loc: Mineral Point, Wi
Re: C/2012 S1 ISON new [Re: Dave Mitsky]
      #6115195 - 10/03/13 01:27 PM

Quote:

In view of the evidence presented above there is a 100% probability that comet ISON will disintegrate. The reason is that it exhibits the same SDE+U-shape signature as comets Hönig and Tabur that disintegrated.




Any study that claims to predict something with 100% accuracy is not 100% accurate in my opinion!


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hiro
Pooh-Bah


Reged: 07/17/07

Loc: Tokyo
Re: C/2012 S1 ISON new [Re: John Wunderlin]
      #6115836 - 10/03/13 06:35 PM

Their analysis is dependent on data gathered by others, brightness reports containing many errors by many persons in the world, and I could not find their accepted reports.

The facts in the history of the comet are as follows:

The length of the dust tail got longer in the past, mere 10 arcseconds in January 31, 2013, and 8 arcminutes in September 30, 2013. Earth distance got about half in the period, and the length got longer by 8x60/10/2 = 24 times in the past eight months. The length got longer very quickly recently, 4 arcminutes in September 16, 2013 and 8 arcminutes in September 31, 2013. The tail got longer by 2 times in the recent two weeks.

Halo was observed first on September 1, 2013 by Juan José González Suárez. I could image the green-tinted halo on September 16, 2013. The halo is another evidence of activity on the surface of the comet, which reached “frost line” in the period.

http://cometografia.es/2013/10/cometas-2013-octubre/

Here is a report by real researchers of astronomy, Karen J Meech and others, which was submitted on August 25, 2013 and accepted on September 9, 2013. This is really nice report containing data gathered with Gemini North 8m scope.

”Outgassing behavior of C/2012 S1 (ISON) from 2011 September to 2013 June”
http://arxiv.org/pdf/1309.2688.pdf

Their last words were as follows.
“While it is unwise to make predictions about the brightness at perihelion when the comet is still far from the sun, especially when it will pass so close to the sun, the run out of these sublimation models show that the comet can still be quite bright at perihelion.”


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CygnuS
sage


Reged: 07/11/11

Loc: The Great Rift
Re: C/2012 S1 ISON new [Re: hiro]
      #6115893 - 10/03/13 07:04 PM

All the uncertainty is fun, educational and exciting. Of course it will be a lot more fun if this thing really does make negative magnitudes.
I've been going through the special edition magazine put out by Astronomy magazine and I really like it.
There are several pages dedicated to October and also January but November and December have night by night break downs of the comet's behavior (and predicted behavior) It will certainly be interesting to see how their magnitude predictions come out.


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PGW Steve
Pooh-Bah


Reged: 10/03/06

Loc: Winnipeg, Canada
Re: C/2012 S1 ISON new [Re: CygnuS]
      #6116499 - 10/04/13 02:11 AM Attachment (40 downloads)

Here is a shot I took on the 27th.
Field is 17.3x13.1 arc minutes.


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Rich (RLTYS)Moderator
Postmaster
*****

Reged: 12/18/04

Loc: New York (Long Island)
Re: C/2012 S1 ISON new [Re: PGW Steve]
      #6116604 - 10/04/13 06:20 AM

Looks good.

Rich (RLTYS)


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BrooksObs
professor emeritus


Reged: 12/08/12

Re: C/2012 S1 ISON new [Re: Rich (RLTYS)]
      #6116793 - 10/04/13 09:12 AM

The recent images of Comet ISON have all been very nice and at first glance impressive, that is until one takes a moment to appreciate their scale.

From a more usual visual standpoint I would hasten to point out that the comet remains a disappointingly small and faint object considering how much closer it has drawn to the Sun over the past couple of months. A more typical comet might be anticipated to be an easy object for at least modest-sized amateur telescopes visually, if not in fact a faint binocular one at this point. However, Comet ISON's coma continues to subtend only a very small dimension in spite of its seemingly impressive photographic tail. At the same time it remains a rather challenging object to see clearly even in fairly large amateur telescopes. Now admittedly the comet's current place in the sky has it in the heart of the morning Zodiacal Light from Earth's vantage point and degrading its visibility, but this does not fully account for how unimpressive ISON appears visually.

On that note I will point out once again that Comet ISON continues to display an intrinsic brightness that is very close to bordering on the survival/non-survival line for comets of very all q at its projected intrinsic brightness. In some ways this seemingly might group it with the presumed behavior of the famous Southern Comets of 1880 and 1887 prior to their perihelia. Hopefully ISON will manage to "hold together" long enough for its nucleus to make it through perihelion and thereby offering the potential for it to develop an impressive tail before dawn in the earliest days of December, but....at this point I would advise observers to keep their fingers and toes crossed!

BrooksObs

Edited by BrooksObs (10/04/13 11:21 AM)


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Tonk
Postmaster
*****

Reged: 08/19/04

Loc: Leeds, UK, 54N
Re: C/2012 S1 ISON new [Re: BrooksObs]
      #6117042 - 10/04/13 11:25 AM

Quote:

Of course it will be a lot more fun if this thing really does make negative magnitudes.




But you will not notice this as a) its only potentially this bright for a few hours around perihelion and b) it will be 1/2 to 1 degree from the sun when brightness peaks

The peak is sharp and of short duration

Example of the predicted light curve is here

http://www.aerith.net/comet/catalog/2012S1/2012S1.html


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m00nless
sage


Reged: 08/06/08

Re: C/2012 S1 ISON new [Re: Tonk]
      #6117166 - 10/04/13 12:21 PM

Is anyone observing the comet visually yet using a moderate sized telescope?

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Parkit
super member


Reged: 08/08/08

Re: C/2012 S1 ISON new [Re: m00nless]
      #6119780 - 10/05/13 10:59 PM

I'm a bit confused. I thought ISON was supposed to be THE big deal starting right around .... now. The last issue of Astronomy magazine I have is from January of 2013 (renewed subscription last week, mostly because of this comet), and after looking closer at it's projected path (pg. 58-59) I can easily see that I'd have to be out at about 5:30am Central time just to TRY to get a glimpse of Comet ISON. It looks from the graphic in Astronomy magazine that the comet's path is through the Spring-Summer sky, and, well, it's not summer anymore. I'm thinking that if we're going to see anything, the best bet is after perihelion? Maybe mid-December?

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CygnuS
sage


Reged: 07/11/11

Loc: The Great Rift
Re: C/2012 S1 ISON new [Re: Parkit]
      #6119842 - 10/05/13 11:58 PM

Great image PGWSteve! Thanks for sharing it.
Parkit, Since your January edition, Astronomy magazine has backtracked a lot. At first they were saying it had a good chance of being the best comet in 400 years but things have changed.
I'm still hoping to get my first view of it on October 15 with my 10 inch SkyQuest Dob. I live in a dark location but have too many trees to the east so I hope I can get some advice from folks here as to whether or not it would be worth it to get up early and load my scope up and move it. I don't want to go to all that trouble if my chances of seeing it are very low.


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canukLX90
professor emeritus


Reged: 12/25/08

Loc: B.C. Canada
Re: C/2012 S1 ISON [Re: CygnuS]
      #6120331 - 10/06/13 10:20 AM Attachment (30 downloads)

Image taken this morning 5:30 - 6 AM
Azimuth 98 deg. Altitude 29 deg
7 X 3 min @ ISO 800 modded 450D and PowerNewt @ F2.8

A 30 second exposure did show the comet. Comet seems to be
developing nicely and fingers crossed it reaches naked eye
visibility in December/ January time frame.

PJ


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