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

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Thu Oct 26 17:20:36 2006
Message-ID: <005901c6f944$8eb421e0$a5714b44_at_ATARIENGINE>

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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Received on Thu 26 Oct 2006 05:20:26 PM PDT