
New Naked Eye Comet - 17/P Holmes
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Replied by mjs on topic Re: New Naked Eye Comet - 17/P Holmes
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- michaeloconnell
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Replied by michaeloconnell on topic Re: New Naked Eye Comet - 17/P Holmes
That's a particularly good one Michael.
It also shows something which I thought I saw in the scope but wasn't sure if it was just me.
About two thirds of the ways out in the halo is a slightly dark band. See what I'm talking about?
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- Frank Ryan
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Replied by Frank Ryan on topic Re: New Naked Eye Comet - 17/P Holmes
Mike S, YOU NAILED IT!
Thats almost an exact match to what we observed in the 20'' last night.
Mike OC,
yip, that band was very obvious in the obsessionator.
I could even see it in the etx125 a few nights ago (see earlier post of mine)
Dave and I both could see a slight 'tail' or, how could I word it...
'impression' of a tail...
very early stages yet but we both saw it when we used a particular filter
(Can't remember which one...Dave?)
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- mjs
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Replied by mjs on topic Re: New Naked Eye Comet - 17/P Holmes
Michael, I thought that I could see that too through the eyepiece but put it down to my eyes.. But there is a hint of it in the image alright. Like looking at a bubble, or a spherical shell of expanding smoke with a slightly brightening towards the outer edge.it also shows something which I thought I saw in the scope but wasn't sure if it was just me.
About two thirds of the ways out in the halo is a slightly dark band. See what I'm talking about?
Another thing I noticed on all images processed is the slightly elongated nucleus??
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- JohnMurphy
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Replied by JohnMurphy on topic Re: New Naked Eye Comet - 17/P Holmes
My estimate is a mag of slightly greater than mag 2.0. It's still getting brighter. What caused it? My guess is an impact with an asteroid.
We (IAS) have asked for Cassini and Hubble to be trained on this unique event but the response is slow.
Canon 350D 30sec @ISO100 3 image composite. Celestron 102SLT. Conditions were horrible, these shots were taken through cloud and full moonlight.
John Murphy
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- dave_lillis
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Replied by dave_lillis on topic Re: New Naked Eye Comet - 17/P Holmes
Great images by all.
Michael S, the image you got is exactly how we saw it, except it was brighter and the mini fan tail was more defined.
I thought the core was at times stellar like but at other times was definitely elongated, I had put it down to seeing or a warm mirror, but now seems to be real.
Frank, we used a IDAS filter, it helped the darken the background while not swamping out the comet although its not the ideal filter for this object.
Michael OC, you are absolutely right about the dark ring/area in the coma, we definitely saw it.
The full moon is a real killer for trying to see anything resembling a tail, anyone used a comet/cyanogen filter on this comet yet ?
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- mjs
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Replied by mjs on topic Re: New Naked Eye Comet - 17/P Holmes
I would agree Dave, there was a much more defied fan shape to the mini tail on Thursday night. It was more squat and diffuse last night...except it was brighter and the mini fan tail was more defined.
Isn't it great to see such dynamic changes fron night to night. Come to think of it it is just great to be able to see it three nights in a row. I do not have much hope for tonight though....
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Replied by dave_lillis on topic Re: New Naked Eye Comet - 17/P Holmes
Did it look bigger last night, it was about 5 arc mins on thursday, if it go to 15 it would become a naked eye disk in the sky, lets hope it gets there. !!
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
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Replied by DeirdreKelleghan on topic post
Comet 17/P Holmes
26 October 2007/ 1200mm/8mm/150X/ Watercolor / Pastels/ Conte
barlows did nothing for the image
I had a 30 minute window in between clouds, to catch this icy visitor in my telescope. I had to shield my scope and my eyes form the moon light by hiding behind my house.
First I looked in my 15X70 binos, and I could see a halo around the comet, a very different view to October 24th, I reckoned this had brightned to around Mag 2.
I popped my 8mmTVP into the scope and oh yes this was a sketch I had to have. So here it is,cloud and rain here in Bray at the moment so most likely not look this evening.
I am thinking up new ways of getting this comet, it is a challenge to sketch as it has so many properties to deal with. Hope it's there for a while longer.
Deirdre Kelleghan
Irish Astronomical Society
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Replied by Seanie_Morris on topic Re: New Naked Eye Comet - 17/P Holmes
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- Frank Ryan
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Replied by Frank Ryan on topic Re: New Naked Eye Comet - 17/P Holmes
if it go to 15 it would become a naked eye disk in the sky
:shock:
That'd be too cool for school.
G'waaan Holmes!
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- mia
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Replied by mia on topic Re: New Naked Eye Comet - 17/P Holmes
Does anyone have an idea what caused the outburst? I've had explanations re the 'missing' tail and why it looks different, but nothing yet re the cause of the outburst.
The most popular explanations seem to be either impact from an asteroid or the ilk, or some reaction from within the comet.
I know it was discovered thanks to a similiar outburst, did they come to any conclusion then what caused it?
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- johnflannery
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Replied by johnflannery on topic Re: New Naked Eye Comet - 17/P Holmes
Legendary comet expert John Bortle has a message on the comet mail list speculating on the possibility of a partial collapse of a section of the comet on itself. Read more at tech.groups.yahoo.com/group/comets-ml/message/12908
On the point of the dark band seen by observers we were speculating today that the band could be the shadow(s) of the bright jet of material from the nucleus projected on the expanding shell -- similar to seeing the shadow of a jet aircraft contrail against the underside of a cloudbank. A way to confirm would be to determine if the shadows rotate at a rate that might be consistent with the bright jet, as the nucleus spins.
Another idea I was mulling over was whether more recent eruptions of material are "shocking" earlier shells of dust puffed off from the nucleus/site of outgassing. I'd lean more towards the former idea but could be way off the mark here on all theories :roll:

Clear skies!
John
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Replied by phoenix on topic Re: New Naked Eye Comet - 17/P Holmes
artics.de/c.rollwagen/public/AC/17P.swf
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- voyager
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Replied by voyager on topic Re: New Naked Eye Comet - 17/P Holmes
Apologies if its been posted but the link below shows how it all started
artics.de/c.rollwagen/public/AC/17P.swf
That's fantastic! It really shows just how dynamic this object is.
Bart.
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Replied by phoenix on topic Re: New Naked Eye Comet - 17/P Holmes
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Replied by dave_lillis on topic Re: New Naked Eye Comet - 17/P Holmes
Chairman. Shannonside Astronomy Club (Limerick)
Carrying around my 20" obsession is going to kill me,
but what a way to go.

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- JohnMurphy
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Replied by JohnMurphy on topic Re: New Naked Eye Comet - 17/P Holmes
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- mjs
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Replied by mjs on topic Re: New Naked Eye Comet - 17/P Holmes
This is the result of some attempt at imaging.
This is the same equipment, settings and processing, as the earlier image taken on the 27th below so the difference in size from the image taken earlier is Real! I also think I can see a hint of a jet at the 7 o'clock position??
Both images were taken through my Dobsonisan so up is up and not north, if you know what I mean, so with 9 hours rotation... 135 degrees??? it is too early for those calculations.
Now is there any way I can sneak back to bed...
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- JohnMurphy
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Replied by JohnMurphy on topic Re: New Naked Eye Comet - 17/P Holmes
www.spaceweather.com/comets/holmes/27oct...ns2a1i1unnn2a1521rh1
John Murphy
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- paulevans
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Replied by paulevans on topic Re: New Naked Eye Comet - 17/P Holmes
We're still in between rain showers here but I'll be getting the 'scope on it shortly.
Clear skies,
Paul.
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- Frank Ryan
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Replied by Frank Ryan on topic Re: New Naked Eye Comet - 17/P Holmes
Some say they can see the expanding shell naked eye.
That 'cone' really does seem to be where the out gassing is occurring.
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Replied by paulevans on topic Re: New Naked Eye Comet - 17/P Holmes
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