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: COMET OUTBURST: Comet 17P Holmes - UPDATE NOV 7  ( 55060 )
drclay
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« : October 25, 2007, 05:53:51 AM »

COMPLETE COMPOSITE IMAGES now posted (scroll to end) From Oct 25 Outburst to November 7 !!
(see NEW posting for observations beginning NOV. 7 2007) at:  http://www.arksky.org/smf/index.php?topic=1445.0

UPDATE November 7 - Latest Image at bottom of sequence
Arkansas Sky Observatory (H45) update on Comet 17P: 
Comet imaged in moonless skies, fair conditions
The comet has maintained steady brightness, both total and nuclear  morphology has not
appreciably changed, and the overall size of the coma has grown considerably, as has the developing tail emerged vividly in P.A. 219 deg.
Coma overall diameter = 11.3' arc (CCD) with increasingly bright offset bright segment as well as possible tail to
SW of nucleus - in PA 219, the previous very bright "knot" of concentration has lessened drastically over the past 72 hours.
Coma appears very large and distinct to the naked eye, perhaps as much as 25 arc minutes
Magnitude, m1 = 2.4, (naked eye) nearly equal to previous night, very distinct cloud to the
naked eye with conspicuous nebulosity and NOW appears to have totally lost the previous distinct yellow color; comparison star (naked eye) is Alpha Per
Nuclear magnitude, m2 = 12.4, continues to drop rapidly as the nucleus becomes even more pinpoint

Overall color is nearly colorless, with slight yellow tint, throughout all expanses of the comet.
NOTE that the updated image posted at the NEW update ( http://www.arksky.org/smf/index.php?topic=1445.0 )  ASO sequence, is in MONOCHROME size there is very little hue of color to the coma at this time.

Equipment: 0.4m SCT @ f/3 CCD, ST402-ME C-I CCD, RGB @ 8 seconds.  Overall magnitude
estimate via naked eye, Alpha Per. by comparison.

UPDATE November 5 - Latest Image at bottom of sequence
Arkansas Sky Observatory (H45) update on Comet 17P: 
Comet imaged in moonless skies, haze and poor conditions
The comet has maintained steady brightness, both total and nuclear  morphology has not
appreciably changed, and although the coma appears to be attaining a more uniformly spread intensity and density, the size has increased only slightly.
Coma overall diameter = 838" arc (CCD) with increasingly bright offset bright segment as well as possible tail to
SW of nucleus - in PA 216, the previous very bright "knot" of concentration has lessened drastically over the past 72 hours.
Coma appears very large and distinct to the naked eye, perhaps as much as 20 arc minutes
Magnitude, m1 = 2.4, (naked eye) nearly equal to previous night, very distinct cloud to the
naked eye with conspicuous nebulosity and NOW appears to be losing the previous distinct yellow color; comparison star (naked eye) is Alpha Per
Nuclear magnitude, m2 = 12.4, continues to drop rapidly as the nucleus becomes even more pinpoint

Overall color is nearly colorless, with slight yellow tint, throughout all expanses of the comet.

Equipment: 0.4m SCT @ f/3 CCD, ST402-ME C-I CCD, RGB @ 8 seconds.  Overall magnitude
estimate via naked eye, Alpha Peg. by comparison.


UPDATE November 4 - Latest Image at bottom of sequence
Arkansas Sky Observatory (H45) update on Comet 17P: 
Comet imaged in moonless skies, high cirrus clouds
The comet has decreased slightly in brightness, both total and nuclear  morphology has not
appreciably changed, but again the overall diameter continues to grow at an extraordinary rate.
Coma overall diameter = 832" arc (CCD) with increasingly bright offset bright segment as well as possible tail to
SW of nucleus - in PA 216, the previous very bright "knot" of concentration has lessened drastically over the past 72 hours.
Coma appears very large and distinct to the naked eye, perhaps as much as 20 arc minutes
Magnitude, m1 = 2.4, (naked eye) noticably dimmer than previous night, very distinct cloud to the
naked eye with conspicuous nebulosity and yellow color; comparison star (naked eye) is Alpha Per
Nuclear magnitude, m2 = 12.2, continues to drop rapidly as the nucleus becomes even more pinpoint

Overall color remains the same, very golden yellow throughout all expanses of the comet.

Equipment: 0.4m SCT @ f/3 CCD, ST402-ME C-I CCD, RGB @ 8 seconds.  Overall magnitude
estimate via naked eye, Alpha Peg. by comparison.

UPDATE November 2 - Latest Image at bottom of sequence
Arkansas Sky Observatory (H45) update on Comet 17P: 
Comet imaged in moonless skies, high cirrus clouds
The comet maintains both brightness and physical attributes; morphology has not
appreciably changed, but again the overall diameter continues to grow at an extraordinary rate.
Coma overall diameter = 638" arc (CCD) with increasingly bright offset bright segment as well as possible tail to
SW of nucleus - in PA 214, now extending to 88.5"" from nucleus, up from previous dates
Coma appears considerably larger to the naked eye, perhaps as much as 17-20 arc minutes
Magnitude, m1 = 2.0, slightly brighter than previous night, very distinct cloud to the
naked eye with conspicuous nebulosity and yellow color; comparison star (naked eye) is Alpha Per
Nuclear magnitude, m2 = 11.6, continues to drop rapidly as the nucleus becomes even more pinpoint

Overall color remains the same, very golden yellow throughout all expanses of the comet.

Equipment: 0.4m SCT @ f/3 CCD, ST402-ME C-I CCD, RGB @ 8 seconds.  Overall magnitude
estimate via naked eye, Alpha Peg. by comparison.

UPDATE November 1 - Latest Image at bottom of sequence
Arkansas Sky Observatory (H45) update on Comet 17P: 
Comet imaged and measured as high cirrus moved in.
The comet maintains both brightness and physical attributes; morphology has not
appreciably changed, but again the overall diameter continues to grow at an extraordinary rate.
Coma overall diameter = 596" arc (CCD) with increasingly bright offset bright segment to
SW of nucleus - in PA 214, now extending to 69.5"" from nucleus, up from previous dates
Coma appears considerably larger to the naked eye, perhaps as much as 17-20 arc minutes
Magnitude, m1 = 2.1, slightly brighter than previous night, very distinct cloud to the
naked eye with conspicuous nebulosity and yellow color; comparison star (naked eye) is Alpha Per
Nuclear magnitude, m2 = 11.1, continues to drop rapidly as the nucleus becomes even more pinpoint

Overall color remains the same, very golden yellow throughout all expanses of the comet.

Equipment: 0.4m SCT @ f/3 CCD, ST402-ME C-I CCD, RGB @ 8 seconds.  Overall magnitude
estimate via naked eye, Alpha Peg. by comparison.

UPDATE OCTOBER 31 - New Image at bottom of sequence
Clear skies prevailed once again.
The comet maintains both brightness and physical attributes; morphology has not appreciably change, BUT overall diameter continues to grow at an extraordinary rate.
Coma overall diameter = 545" arc (CCD) with increasingly bright offset bright segment to SW of nucleus - in PA 220, expanding to 45" from nucleus, up from previous dates
Coma appears considerably larger to the naked eye, perhaps as much as 12 arc minutes
Magnitude, m1 = 2.3, slightly brighter than previous night, very distinct cloud to the naked eye
Nuclear magnitude, m2 = 10.2, substantially dimmer than previous night and nucleus is very starlike
Overall color remains the same, very golden yellow throughout all expanses of the comet.

Equipment: 0.4m SCT @ f/3 CCD, ST402-ME C-I CCD, RGB @ 12 seconds.  Overall magnitude estimate via naked eye, Alpha Peg. by comparison.


UPDATE: October 30
Comet continues a plateau in brightness, but continues to enlarge; details are as follows (NOTE current image at bottom of this page)
Coma Diameter, overall:  482", average 4 CCD measures
Jet images emanating at nucleus and extending SW into coma
Nuclear Magnitude (m2) = 9.4 , slightly brighter within previous 24 hours
Total Magnitude (m1) = 2.4, constant
NOTE outer halo continues to enlarge and intensify relative to darker inner void (?) ring
SEE image in composite, following

UPDATE: October 29
Comet is now maintaining somewhat of a plateau in both overall brightness and size; details are as follows (NOTE current image at bottom of this page)
Coma Diameter, overall:  408", average 8 CCD measures
Jet images emanating at nucleus and extending SW into coma
Nuclear Magnitude (m2) = 9.9 to 10.0
Total Magnitude (m1) = 2.4, slightly down from previous night.


UPDATE: October 28
The comet has increased dramatically in size and complexity; (see LAST image on this page) details are:
Coma diameter, overall:  348.3" (average 8 measurements, CCD)
Coma inner core (bright) diameter: 117.3"
Dark "compression/shock" ring in outer coma:  204.2"
Nuclear magnitude - 9.8 (ave)
Total magnitude = 2.3

NOTE that even though the comet is considerably larger on this morning than on the previous morning, the brightness overall has dropped (naked eye estimate utilizing Alpha Perseii and Alpha Cassiopeia).
.
-----------------------------

October 27:
Even more incredible each night; the comet now measures 255 arc seconds across (via CCD direct measure), and is magnitude 1.9 visual (10 x 50 binoculars); this 5-second RGB composite was taken with the 0.4m SCT f/3 via CCD at 09:55 U.T. and the field measures 6 x 6 arc minutes.  The nucleus was measured photometrically at m1=11.8, offset significantly from center; also note the very bright opposing (from the nucleus) scintillating condensation equally offset from center, but in the opposite direction. 

From Oct. 25:
What an incredible sight....to the naked eye, it appears as a bright new star in the constellation of Perseus, high in northern skies and never rising nor setting throughout the nights of the next few weeks.

Comet 17P Holmes, a very obscure and dim object to say the least only 30 hours ago, is blazing away at a brightness increase never seen before in such a short period of time, rising more than 15-16 magnitudes since October 23.  Now at brightness 2.0 (ASO, Oct. 25 UT, 04:10) and perhaps still brightening, this comet must be watched continuously for the next several weeks.

It appears as you seen in the first light photo from ASO; this is an RGB color image from an ST 401-ME camera, 12 second images in each color and combined.  No post processing, just a raw image, showing the brilliant round yellow-green huge (nearlly 3 arc minutes across) coma.  Very high contrast negative imaging reveals a possible dust tail coming nearly due north (down) from the comet as well as one streaming from the south side of the coma.

The field of view in the Oct 25 image is 12 arc ' by 7' with SOUTH up.  Oct. 27 image is 6' x 7' arc, scale is identical on both.

The comet is presently as bright if not brighter than any star in both Perseus and Cassiopiea and could continue to brighten.

Dr. Clay

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* compositeOct25_29.jpg (61.51 kB, 1000x1200 - viewed 10124 times.)

* 17P_Nov5_0400.jpg (27.01 kB, 880x640 - viewed 5293 times.)
« : November 07, 2007, 04:26:55 PM drclay »

Dr. Clay
drclay@tcworks.net
ASO Petit Jean Mountain /MPC H41
ASO Petit Jean Mountain South /MPC H45
ASO West Conway /MPC H43
.......serving astronomy since 1971
els1958
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« #1 : October 28, 2007, 02:27:25 AM »

I just came in from viewing the comet 17P.  Remarkable.!  I started with 7x40 binoculars and not really expecting much.  But WOW!, this is one incredible sight.  I immediately set up my LX200 10".  In very urban skies, the amount of detail was surprising.  The nucleus appeared like a bright background star - pin-point - just off center.  Using a 24mm panoptic, the comet appeared to consume 20% of the FOV width.  What's that, about 4-6 arc minutes? Thought you might like an urban report.

Eric Smith
Ray Brooks
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I wish I didn't work nights!


« #2 : October 28, 2007, 03:24:44 AM »

I'm at work right now (10:20 pm) in downtown Little Rock and can see it naked eye through the city lights.

I got my little Tasco 8x21 binocs out of my car and was stunned.  Can't wait to get a scope on it!!

How ya doing Doc?
Brian Emfinger
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« #3 : October 30, 2007, 12:50:54 PM »

addition: November 8, 2007.  I made a little video of the expansion > http://www.realclearwx.com/comet17pholmesvid.htm[/u][/color] and more pictures here = http://www.realclearwx.com/comet17pholmes.htm

Here is another sequence showing the growth of the comet in comparison with how large it has become in comparison with the moon from October 24 - November 8



http://www.realclearwx.com/110807a.jpg

Previous Picture from November 5= http://www.realclearwx.com/11020401.jpg

Previous Picture from October 30= http://www.realclearwx.com/1030071.jpg


« : November 08, 2007, 07:22:43 PM Brian Emfinger »

Brian Emfinger
      Ozark, AR
www.brianemfinger.com
kingfish
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« #4 : October 30, 2007, 07:45:30 PM »

Great job Dr. Clay on keeping us updated on the evolution of this spectacular comet.  Keep it coming.

Dan Lamoreaux
Tulsa, OK
petevasey
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« #5 : November 09, 2007, 10:28:55 AM »

It would appear that the cloud of gas forming the ion tail has moved away from the main coma, possibly under solar wind pressure.  Any ideas??

10 x 3 minute RAW subs with unmodded Canon 350D. William Optics ZS66 with Meade .63 reducer.  Cropped from full frame (the corner stars are distorted).  The bright star is of course Mirfak. (Mirphak?). Mid sequence time 2140 UST.

Median combined in Deep Sky Stacker.

I see the same shapes with images taken with my Artemis 285 and a 135 mm lens at the same time, so it isn't an artifact, but this image is nicer  :wink:

A 'deep'  image from a couple of days earlier (next posting due to size restrictions) shows a similarly shaped cloud of gas next to the coma - could this be the mass that has detached?  (SBIG ST-8XME and TMB505 refractor)

Peter.

[attachment deleted by admin]
« : November 09, 2007, 05:37:51 PM petevasey »
petevasey
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« #6 : November 09, 2007, 10:30:08 AM »

And here is the image from a couple of days earlier (see above post)

Peter.

[attachment deleted by admin]
petevasey
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« #7 : November 09, 2007, 05:46:42 PM »

And another pic showing the detached tail, but not heavily stretched, so more natural looking, with structure visible in the coma.  10 x 1 minute RAW frames with 350D on ZS66 as above.

Peter

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