[Atmob-discuss] Comet 17P/Holmes

Sat Oct 27 13:17:25 EDT 2007

Everyone is commenting on how weird this comet looks. I think Alan
MacRobert on the S&T website explains that when he writes:

"As for a tail: I expect it'll be short and stubby when or if it even
forms. The tail should be pointing nearly away from us in space — we're
looking down its length — since the comet is nearly on the opposite side
of Earth from the Sun. From the comet's viewpoint, the Earth and Sun are
only about 15° apart, and this phase angle will stay small for many
months. So we'll still be looking down the tail."

How often do we see a comet head-on like this one?

I haven't seen this comet yet. I tried for it Thursday night with 7x50
binoculars, but there were too many clouds, and I didn't stay out unil
the wee hours of the morn. I heard that it's supposed to be clear Sunday
night, so I'll take my 5-inch RFT refractor out and plan to stay up way
past my usual bedtime.

Tal

On Sat, 27 Oct 2007 10:44:29 -0400 Mario Motta <drmariomotta at gmail.com>
writes:
Good idea. Mine was at midnight, will suggest all note time of image for
any future postings, and make it part of the image name.

Mario

John Boudreau wrote: 
Very nice catch Mario!

Visually in a 140mm refractor at 88x, I saw a faint but noticeable
'spline' appearing to come off a starlike nucleus plus 2 large and
essentially concentric shells. Perhaps that 'spline' is the jet-like
feature you've recorded. Unfortunately mount electronics gremlins
prevented me from doing any imaging--- hopefully I've cured then for the
next clear night. I hope the outburst lasts for a while...

BTW--- Since others have reported possible changes in the appearance of
the region of the nucleus over a few hours, for comparison purposes it
may help to post the time of the images in their descriptions.

---John

----- Original Message ----- 
From: "Mario Motta" <drmariomotta at gmail.com>
To: <mmotta at massmed.org>
Cc: "AAVSO-DIS" <aavso-discussion at mira.aavso.org>;
<atmob-discuss at atmob.org>
Sent: Friday, October 26, 2007 2:48 AM
Subject: Re: [Atmob-discuss] Comet 17P/Holmes

Sorry, here is the direct link to the comet Holmes image, the other is 
the gallery itself:

http://www.atmob.org/gallery/showimage.php?id=704

Mario Motta wrote:

OK, I just uploaded an image of Comet Holmes, about mag 2 visual.
it is on the ATMOB website, wingaersheek gallery. Direct link:

http://www.atmob.org/gallery/showgallery.php?id=43

This is without doubt one of the weirdest things I have ever seen! 
Visually it has a dense central core, with a small fan splaying to the 
west, surrounded by a large shell, looks like 2 concentric shells. Has 
the appearance of a planetary nebula with a bright central star.
I suspect it must have split in at least 2 pieces and must be spewing 
out volatiles. But why, and so far from the sun?? Anyone got real data 
on this thing?

Mario Motta

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