[meteorite-list] 17P/Holmes magnitude graphs & images

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Sun, 28 Oct 2007 02:20:30 -0500
Message-ID: <04c501c81933$061ba280$b92ee146_at_ATARIENGINE>

Hi,

    Similar tale for me. Solid cloud cover, day and
night, since before the first news of the outburst,
but it cleared today. I went out as soon as it got dark,
before moonrise, and with no stars even visible yet,
faced the NE, and raised my 40-year-old 7x50's
from the horizon upward -- and it was the first thing
I saw!

    I would have estimated the coma in the binoculars
at nearly the width of a full Moon, but as soon as
the Moon rose, the glare reduced its appearance to
half that. Air quality and seeing were lousy, or worse;
when Capella rose, it was green and red and white
and I thought it was an airplane until it didn't go
anywhere.

    Despite the very turbulent and scintillating air, I
thought it might be worthwhile dragging the 100's
of pounds of cast-iron-mounted telescope (built
in the 1950's on the theory that a good telescope
mount needs lots of mass to stabilize it) and have
a look.

    About half-way through the dragging I began to
regret the decision but I persisted until I had it out
in the middle of the asphalt road (which was the
only place I could see the NE sky from). My relict
mount scope (free of spotting scope and circles)
holds a 6-inch mirror, classic f8. I used a 40mm
wide field eyepiece yielding 30X and swept up the
comet.

    I see a diffuse coma about 16 arc minutes across
and a brighter "inner coma" about 5-8 arc minutes
in diameter with a sharp "condensation" of brightness
near the edge of the "inner" coma. Outside the diffuse
coma is a "green glow" that extends about another
8-10 arc minutes. I call it "green" but frankly, to me,
the color seemed more like a greenish cyan. I saw
no yellow in the central coma, only a pure white
luminosity.

    The relative dimensions of comas and glows are
dependent on the darkness of the background sky, and
I'm wagering that if the comet retains its brightness for
one to two more weeks, everyone will exclaim how the
outermost coma has grown, once that Moon is gone.

    It is a very odd looking comet. The boundaries of the
coma(s) seem very sharp. Someone (was it Larry Lebofsky?)
said it looked like a planetary nebula, and it truly does, as
if the coma material had been thrown off in short, sharp
"bursts" or explosions and had expanded in two "shells."

    There are "hints" of some interior structure, but the
seeing at my location was too poor to be sure. It helps
that the comet gets near the top of the sky where the
best seeing is, if there's any good seeing to be had.
Maybe when we can get that Moon out of the sky...
As always, those with the darkest skies will see the
most.

As for those puzzled by the decision to use an ancient
6-incher instead of the ubiquitous and bigger Schmidt-Cass
(I got one), the 6-inch has a very accurate figure. When
it was new, it tested at about 1/120th wave, and it's really
good for detail work, very sharp.

    Now all I need is stiller, quieter air, a big can of
Moon-Be-Gone, and to get my neighbors to turn off
all their lights and go to sleep at 8 pm... Thankfully,
it looks like Holmes will continue whatever it is that it's
doing for a while. By Tuesday, we'll have three hours
of dark before Moonrise, and an hour more every day.

    I was still in the middle of the street when my nearest
neighbors came home after midnight and missed crushing
me (and wrecking their car on all that cast-iron): "What are
you doing in the middle of the street?" I explained that I was
looking at a newly brightened comet and started the point-
at-a-star routine, and before I could get the directions on
where they should look out of my mouth, they exclaimed,
"Omigod, I see it! It's all fuzzy!" .


Sterling K. Webb
----------------------------------------------------------------------
----- Original Message -----
From: "Darren Garrison" <cynapse at charter.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Saturday, October 27, 2007 10:44 PM
Subject: Re: [meteorite-list] 17P/Holmes magnitude graphs & images


First clear night since the brightning--- found it quickly and easily with
cheap
binoculars, fuzzy eyes, ever-worsening skies, and the year's brightest full
moon.
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Received on Sun 28 Oct 2007 03:20:30 AM PDT