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(meteorobs) fwd: Re: **COMET HALE-BOPP OBSERVATIONS: 2/25/97 at 1050 hrs...
I know this is long, but Dave Knisely did such a wonderful job with this, I
hope no one minds.
Please e-mail me if you object.
Wayne
-------------
Original Text
From: wayne.t.hally@tek.com (Wayne T. Hally), on 2/25/97 5:29 AM:
To: <wayne.t.hally@tek.com>
SUBJECT too long. Original SUBJECT is 'Re: **COMET HALE-BOPP OBSERVATIONS:
2/25/97 at 1050 hrs UTC. "Get out and see it!"'
---------------------- Original Message Follows ----------------------
In article <33135ACD.1FD0@navixdot net> "David W. Knisely" <dk84538@navixdot net>
writes:
>From: "David W. Knisely" <dk84538@navixdot net>
>Subject: **COMET HALE-BOPP OBSERVATIONS: 2/25/97 at 1050 hrs UTC. "Get
out and
>see it!"
>Date: Tue, 25 Feb 1997 13:34:05 -0800
>This is a multi-part message in MIME format.
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>Forget the cold. Forget the moon. The comet looks great (color AND
>detail), so get out and see this thing now! Below is the latest update.
>David W. Knisely, KA0CZC email: dk84538@navixdot net
>Prairie Astronomy Club, Inc. http://www.4w.com/pac/
>Attend the 4th annual NEBRASKA STAR PARTY, AUGUST 2-9th, 1997
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> COMET HALE-BOPP 1995o1 OBSERVATIONS 2/25/97 at 1050 hrs UTC
> from Beatrice, Nebr., USA: 40.29N, 96.75W, 1380 ft. elevation
> by David Knisely
>CONDITIONS:Clear, Temp. 14 deg. Wind S. 5mph Humidity: 84%
>Naked-eye limit: +5.1 Seeing 1" arc. Moon: Gibbous (4 days past full)
>EQUIPMENT: 10x50 Binoculars, 10 inch f/5.6 Newtonian (47x, 94x, 141x,
220x)
>COMET ESTIMATES: POSITION: R.A. 21h 3.6m Dec.+30 deg. 37' (Cygnus)
>Head Visual Magnitude: +1.0 (comparable star Deneb, vmag +1.25)
>Coma Width: 14 min. of arc (by timings).
>Coma length: 13 min. of arc (approximate).
>Degree of Condensation: 7
>Tail Length: 5 degrees (moonlight interfering with length estimate).
>Naked-eye Observations: VERY NICE! The comet is a very obvious object,
>appearing as a bright yellowish fuzzy star-like object of the first
magnitude
>with a faint fan-like tail extending to the northwest. A narrow
brightening
>or tail streamer could be glimsed with the unaided eye extending for over
a
>degree northwest of the nucleus. The outer tail was quite diffuse, with
>hints of a narrow plasma tail along the northern portion of the tail.
Only
>the inner-most two degrees of tail was very bright.
>10x50 Binocular Observations: The comet's inner coma (especially south of
the
>nucleus) has a definite yellowish hue, with the eastern portions of the
coma
>having a more bluish tint. The inner core was very bright, and slightly
>elongated north to south, with a hint of the southern fan seen on the
14th.
>The tail was bright in the innermost two degrees, and extended in a
position
>angle width at the nucleus of about 40 degrees. The plasma tail could be
seen
>on the northeastern side of the main tail as a very faint narrow streamer
>perhaps 5 degrees in length. The inner core of the dust tail was linear
and
>bright, almost looking like a streamer. The dust tail could be followed
to
>almost four degrees.
>10" f/5.6 Newtonian Observations: SPECTACULAR! At 47x, the coma and inner
>tail gave the comet a somewhat parabolic look, with a brilliant inner core
>and a long broad darker zone running northwest from a point just downtail
of
>the nuclear condensation. The forward portion of the coma was rounded and
>diffuse, with the southern and western portions being the brightest. The
>brilliant nuclear condensation was about 7 minutes of arc inside the
coma's
>front edge, and was non-stellar. It was also an off-white color similar
to
>that of Jupiter. Coming off of the condensation was a bright dirty
yellowish
>curving fan of light, which was close to 90 degrees in position angular
>width, and could be traced over 3 arcminutes southwest from the nuclear
>condensation. Its brightest portion contained an irregular jet which ran
at
>P.A. 100 degrees for about 3 arc minutes before curving gently to the
west.
>The inner portions of the fan near and just to the west of the nucleus
>appeared distinctly mottled. The fan curved in a half-spiral form to flow
>downtail into a bright narrow streamer or dust tail core, which could be
>followed to nearly two degrees from the nucleus. Mean position angle for
the
>tail was about 320 degrees. Hints of another much fainter outer streamer
>along the western side of the tail were also glimsed.
> The outer portions of the western side of the inner tail had a faint
but
>quite striking reddish tint to them. The northern edge of the fan seemed
to
>change from yellowish to a bluish color, and marked the boundary of the
>parabolic dark zone downtail from the nucleus. To the east of the nucleus,
a
>weak narrow curving jet appeared to mark the other side of the dark zone,
as
>it flowed and curved into the plasma tail. The eastern portions of the
coma,
>along with the northern edge of the fan were all distinctly bluish, which
>contrasted nicely with the yellowish color of the fan, and the red or
>orangish tints along the west side of outer coma and dust tail.
> At 94x, the detail in the bright inner fan was remarkable. The nuclear
>condensation appeared slightly elongated north to south, with a point-like
>northern edge. No distinct star-like nucleus could be seen for certain,
and
>the nuclear condensation at times looked like a tiny inner fan or oval.
The
>yellowish color was even more striking at this power, as was the bluish
cast
>of the eastern portions of the coma. The bright fan-like plume contained
>at least two small irregular arcs of light with a roughly wave-like form
to
>them. The outer arc was about 29 seconds from the nuclear condensation,
>while the inner one was about 17 seconds of arc out. Hints of very faint
>mottled detail beyond 40 seconds out were also glimsed. Each arc was very
>irregular, and both ran from P.A. 90 degrees through 280 degrees. The
inner
>arc was connected to an oval hazy patch near P.A. 270 degrees, which
touched
>the nuclear condensation on its western side. A fainter patch could also
be
>seen just to the east of the nuclear condensation. The faint plume at
P.A.
>90 degrees may have been a contrast effect between the dark zone north of
the
>nucleus and the inner plasma tail.
> At 141x, the arcs showed even more detail. Portions of them ran
straight
>for a few arcseconds before curving again. At 220x, each arc contained
weak
>knots or filamentary detail, and the nuclear condensation looked more like
>the inner core of the fan, coming to a distinct point on the north side
when
>seeing improved. At no time, however, was a star-like point seen with any
>certainty anywhere in the condensation. The jet-like feature at P.A. 100
>degrees broke up as it crossed the arcs, and did not look very distinct
even
>beyond them.
>David Knisely
>
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