[meteorite-list] Rob's Comet's Exciting Explosion Part II

From: MexicoDoug <MexicoDoug_at_meteoritecentral.com>
Date: Thu Oct 26 18:00:06 2006
Message-ID: <00f401c6f94a$0c487890$4e53a4ac_at_thedawning>

Sterling wrote:

"Before you blithely believe the "naked-eye" or pair of binoculars
propaganda, that is only true if you are lucky enough to be somewhere that
is truly DARK, completely and totally dark, and such spots are rare today."


Hi Sterling, Yes, I am literally in heaven with this beautiful comet and it
is nothing like when you and I battled to see it. BUT, RECONSIDER - THE
COMET IS EASY WITH the Safeway special Binoculars!

Now it is high in the sky 30-45? above the horizon (nearly half way to the
zenith) an hour or two after Sunset. That's way above out of the sky glow
for continental US latitudes and better for Europe on the average, moving
fast as heck. It was supposed to be really spent by now and less
interesting, but the "outburst" which I insist calling an explosion in its
own rite which resulted in a 5-10 times brightening, has brought this comet
up from being an average piece of eye candy to a truly awesome one. I saw
it with my eye in underpants (well, how can I call it a naked eye if I
needed to put on the eyeglasses) which I estimated the night it blew up to
have reached 4.4 magnitude which seems to be in agreement with more and more
observing reports that have come out (3.8 to 4.6 is the range I have seen).

The comet is visible from metropolitan areas. If you can make out all the
stars in semicircula Corona Borealis, you can see the comet. It's awesome.
The tail (nicely captured on the effectively comet-tracking exposure posted
by Thomas - this is the view no one can see, only a camera accumulating
light). Birding glasses are fine, any binocular will work including my
bright opera glasses. Really it will, no BS. You can see the comet in
twilight, with binoculars, too. This is a great burst of light. I bet, if
you get a keyhole in the clouds you can look just under the keystone and
above the crown and you will easily see it with the Wal-Mart special
binoculars. Of course, it will loke like the pictures I posted a couple of
days ago, like a little green galaxy popping out of the field in the binocs.

Good luck to everyone. This really is an incredible comet. The color is
cool, the shape is ovalish, the tail challanging, though. It's everything a
comet should be for a fun look a it. and yes right from your back yard
(unless you have clouds or have dificulty seeing any stars in your
sky....thanks to the great brightening it experienced since Sterling and I
were blabbing about it in the beginning of the Month.

On Ed's question, and as a complement to Sterling's rundown of the orbit.
As this comet was on a hyperbolic orbit (well, that is what is most
probable, though these things are hard to say with certainty with alleged
intragalatic small body wanderers, the approach at a smaller fraction of an
AU to the Sun definitely softened it up a great deal, since it may never
have been so close to a star before). Rather than expect the comet to blow
up at the moment it is at perihelion, think of it more like a crock pot slow
cooker with relatively a lot of mass: at close approach the temperature is
still on the ramp up stage which continues for weeks afterwards. (Nice to
think of the Sun as a light bulb cooker like the old Barbie doll ovens many
of you probably shoved mud in to your sister's indignation when when she
baked bread in them)

All kinds of things at the hot Solar radiation level induced temperatuve
between Earth and Venus start happening and breaking down on the skewing
surface. The as it reached say 1 AU it is still very much in the heat. Just
like the melting of glaciers and sudden sloughing off - instead immense
glacier activity happening right on on say June 21 (facing solstice), it
will happen in late Summer as the crock pot is still quite hot and going.
It isn't like there is a terrorist ready to set off a bomb on the comet,
just maybe some mushing arounds on the surface. That's the way I think of
it anyways, gravity is strong, but a secondary culprit. The comet has a
simmering case of gas and two nights ago ... we saw the result break free.
Let's call it the Dog Days of the comet! OK, I'll get Sirius...

Best wishes, Doug




Part II


> Hi,
>
> The preliminary orbit published in July said Comet 2006
> M4 would make the big turn around the Sun on September
> 28, 2006, at a distance of only 0.132 AU or 12,225,000 miles.
> The orbit has since been corrected and the closest approach
> to the Sun was 0.793 AU. The closest approach to the Earth
> was yesterday! But it was at a distance of 0.999 AU. Not
> exactly a close call! And hardly likely to be the cause of
> a gravitational breakup event.
> You can see its orbit in an animated movie at the JPL
> Small-Body Database. The movie can be progressed forward
> and backward at will (you have to have Java to run the applet):
> http://ssd.jpl.nasa.gov/sbdb.cgi?ID=dK06M040;orb=1;cov=0
> Rob's Green Monster is a one-time pleasure; it's leaving
> the Solar System, never to return. It's in a hyperbolic orbit,
> probably because whatever deflected it inward toward the
> Sun gave it an extra good push. The comet came in below the
> ecliptic plane, crossed the plane August 19-20, and is now
> above it.
> I spent three nights finally getting a sight of the comet
> in early October, from deep inside the Midwest Murk. As
> for my chances of actually SEEING it now...? Anyone who
> tried to watch Wednesday's World Series Game (rained out)
> has a perfect picture of my observing conditions! I live
> exactly 26.5 miles from the stadium in a little river town
> on the east shore of the Mississippi River
> The river is bordered by sheer limestone bluffs 150-250
> feet high, while the west shore (in Missouri) is a flood plain
> and the much lower bluffs there are 25-30 miles inland from
> the river (the river was that wide once, carrying the
> glacial melt).
> There is a park is 235 feet up, on the very verge of
> the river, not lit, and has an outlook spur with a clear
> view. Skyglow is south and behind, and the land to
> the northwest contains no city of any size for hundreds
> of miles.
> Before you blithely believe the "naked-eye" or pair of
> binoculars propaganda, that is only true if you are lucky
> enough to be somewhere that is truly DARK, completely
> and totally dark, and such spots are rare today.
> I spent three nights in a row up there in early October.
> The first with good binoculars and had no luck. The
> second with good BIG binoculars, tripod and camera,
> and had no luck. Finally, I disassembled a large astronomical
> telescope, stuffed it into my car, re-assembled it in the park,
> set it up and waited for dark. It's a nice comet, worth the
> work.
> But I hope nobody thinks they're going to set out into
> the backyard with their birdwatching bino's and take a
> peek, unless they happen to live in a pool of inky blackness.
> You can tell that Doug is really happy to see it; he
> was having a tougher time than I was, as his location
> is not a favorable one. I just hope that Rob has gotten
> a good look at "his own" comet!
> Me, I hope the comet continues to fragment (a not
> unlikely prospect) and becomes a true naked eye object
> of magnitude 3 or even 2! Then, even those birdwatching
> bino's in the backyard will be enough!
>
>
> Sterling K. Webb
> ---------------------------------------------------
> ----- Original Message -----
> From: "E.P. Grondine" <epgrondine_at_yahoo.com>
> To: <meteorite-list_at_meteoritecentral.com>
> Sent: Thursday, October 26, 2006 11:08 AM
> Subject: Re: [meteorite-list] Rob's Comet's Exciting Explosion Part II
>
>
> > Hi Doug -
> >
> > I wonder why Rob's come frgamented up at this
> > particular time. Where was Rob's comet at in terms of
> > the plane of the ecliptic? Had it just passed a nearby
> > large gravitational body?
> >
> > good hunting,
> > Ed
> >
> > --- MexicoDoug <MexicoDoug_at_aim.com> wrote:
> >
> >> Hello Listees,
> >>
> >> Rob's green Comet has exploded. This is fascinating
> >> and this is big news for Comet people. OK, I should
> >> say it had an unexpected outburst and just got 5-10
> >> times brighter while it was just on its way out and
> >> ready to wane quickly. I'm sure if we were on the
> >> comet that would be a mean explosion. It now kicks
> >> the butt of SW3 in brightness. As the Moon is
> >> getting stronger, Wednesday night (tonight, and
> >> maybe one more night) is basically the last chance
> >> unless something else fantastic happens like just
> >> did to this comet 10 hours ago or so.
> >> Congratulations, Rob, your Comet just turned into
> >> one of the top 5 of the last decade!
> >>
> >> The outburst is nice! Here's a comparison with a
> >> normal consumer digital camera nights of , widest
> >> angle setting (35mm equivalent zoom setting of a
> >> 35-200). Lat. _at_ 30?24' 20:50PM EDT (same time, 120
> >> min after Sunset, and place both days).
> >> Transparency was a little worse the second night,
> >> but a great Milky Way sky both times.
> >>
> >> www.diogenite.com/061024-25.jpg
> >>
> >> The top is the evening of 2006 Oct 24.06 which is:
> >> C/2006 M4 (SWAN) 2006 Oct. 24.04 UT: m1=5.9, Dia.=
> >> 8', DC=7 above average transparency vis. LM = 6.0
> >>
> >> The bottom is the evening of 2006 Oct 24.06 which
> >> is:
> >> C/2006 M4 (SWAN) 2006 Oct. 25.04 UT: m1=4.4, Dia.=
> >> 8', DC=8 average transparency vis. LM = 5.6
> >>
> >> If you want to see the magnitudes of the comparison
> >> stars in the side-by-side photo above, they here is
> >> a star chart showing the positions of the comet both
> >> nights and magnitudes of the stars.:
> >> www.diogenite.com/mag.jpg
> >>
> >> The "C" shaped constellation is Corona Borealis,
> >> just under Hercules and headed the Strongman's way.
> >> You can see how much the comet moved in two night
> >> and guess very accurately based on that where it
> >> will be tonight. It is not hard to find with
> >> binoculars. The comet is WNW.
> >>
> >> The camera and photos were the same, however it was
> >> somewhat colder the first night and better
> >> transparency, so the raw photos presented would have
> >> to be adjusted - better to just compare to their
> >> respective comparison stars.
> >>
> >> Outburst +1.5 magnitude brightening!! First comet I
> >> have seen naked eye since Kohoutek, thanks to the
> >> dark sky location. Still, C/2004 Q2 Machholz was
> >> more impressive in the binoculars, though. This
> >> comet looked like a bright galaxy through the 10x50
> >> consumer binoculars and during the most steady view
> >> through them, a short tail could be seen - but only
> >> under
> >> optimal conditions. The size of the comet reported
> >> was estimated in a 89mm Mak-Cassegrain telescope.
> >>
> >> Best wishes, Doug
> >>
> >> ----- Original Message -----
> >>
> >> Sent: Tuesday, October 24, 2006 6:03 PM
> >> Subject: Re: 2006 M4 (SWAN) dramatic brightening
> >>
> >>
> >> > > Easily visible in Nautical twilight? I just saw
> >> M4 last time from a
> >> > > dark sky, and it was similar to M13 in
> >> magnitude. Is something
> >> > > changing - this bright magnitude sounds too good
> >> to be true? Can
> >> > > someone else kindly confirm as it would be worth
> >> a 100 miles trip
> >> > > now?
> >> > >
> >> > > I'll upload a photo of Corona Borealis and the
> >> comet from a section
> >> > > of wide angle 35mm equivalent of the normal 135
> >> film camera. It
> >> > > isn't good, but the comet is perceptible and
> >> green 2006 Oct 24.04 UT.
> >> > > (Taken last night EDT about 8:52 PM, 15 seconds
> >> exposure)
> >> > > www.diogenite.com/061024-06UT.JPG (should have
> >> been saved as
> >> > > 061024-04, not -06) Latitude 30?24' Vis. LM 6.
> >> > >
> >> > > The lower two stars of the "C" of Corona
> >> Borealis point to the comet
> >> > > which is dim but the greenest speck on the
> >> image, half way from the
> >> > > most counterclockwise star of CrB to the upper
> >> right corner of the
> >> > > image.
> >> > >
> >> > > I'm not comparing this to the nice photos
> >> recently posted on the
> >> > > internet, but posting it to to compare the
> >> > > magnitude...photographically at least... less
> >> than 20 hours ago....
> >> > >
> >> > > Thanks kindly, Doug
> >> >
> >> >
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> >>
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Received on Thu 26 Oct 2006 05:59:42 PM PDT