cildarith
Carpal Tunnel
Reged: 08/26/04
Posts: 2122
Loc: San Diego, CA
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This morning the smoke and ash had cleared sufficiently for a view of this unusual event, so I dragged myself out of bed for a quick look and sketch.
17P/Holmes
Periodic Comet
Parks Astrolight EQ6 • 6" f/6 Newtonian Reflector
7.5mm Parks Gold Series Plössl • 120x, 26' Field of View
Filter: NIOSH N95 Particulate Respirator 
26 October 2007 • 09:45-10:15 UT
On the 23-24th of October, 2007 Comet 17P/Holmes experienced a major outburst, increasing its brightness 1 million times in just a few short hours, rising from 17th to 2nd magnitude. Such events are usually caused by the sudden release of gas and/or dust particles from the comet (the yellow color suggests the latter, in this case). During the early morning hours of October 26, the smoke from the Southern California fires had cleared sufficiently to make this observation. To the unaided eye, 17P rivaled the brightest "star" in the constellation Perseus – appearing only slightly less prominent than magnitude 1.8 Alpha Persei (Mirfak). In 10x50 binoculars it had a bright yellow hue and looked slightly fuzzy or unfocused.
Through the eyepiece of my telescope the golden hue was striking as was its brilliance, near-perfect circular symmetry, and sharp stellar pseudo-nucleus. It resembled a huge, bright, yellow planetary nebula about 4' in diameter. At high magnifications (120x, 240x) the central regions of the comet displayed considerable detail. A bright arc of material extends from the nucleus from south to west, with three prominent streamers involved in and extending from this arc. The circular coma has a somewhat annular appearance. Beyond the bright circular coma, two faint plumes of material, one to the northwest (elongated) and the other to the south-southeast (very broad and diffuse) could be detected by gently rocking the scope from side to side.
This comet was discovered by British astronomer Edwin Holmes on November 6, 1892 while conducting observations of the Andromeda Galaxy (M31). The entirety of its 6.88 year orbit is spent between the orbits of Mars and Jupiter.
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WadeVC
Carpal Tunnel
Reged: 12/02/05
Posts: 2799
Loc: Lodi, California,
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OMG...I forgot that you are down in the area where the fires are burning. I hope is all well with you on that end Eric.
Nice sketch of the comet. Glad to see that you were able to observe this nifty visitor from space. Nicely done! 
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Orion XTi10 f/4.7
Orion XTi8 f/5.9
Meade NGC 70mm f/10
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My Sketch Gallery
My Astronomy Blog
A wise man can see more from the bottom of a well than a fool can from a mountain top.
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Dee
professor emeritus
Reged: 03/12/06
Posts: 646
Loc: Ireland
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That is an outstanding sketch of this comet  and I think another is in order.
Dee
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pike_fly
sage
Reged: 10/10/07
Posts: 365
Loc: Roxborough Park, Colorado
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Beautiful observation Eric - what power does the enlargement represent. I didn't knotice the man when viewing last night, but I didn't go much past 90X. I was having a hard time telling if I was in focus without a star in view.
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Lee
8" Celestron f6 Dobsonian
10" Zhumell Dobsonian
Class 4 Bortle Scale Backyard Site
View Lee's Gallery
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cildarith
Carpal Tunnel
Reged: 08/26/04
Posts: 2122
Loc: San Diego, CA
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Wade: Thank you! We're doing just fine at this point, aside from the wretched air quality...
Dee: Thanks very much, I'm glad you like the sketch.
Lee: Thanks! The observation was made using both 120x and 240x, but in this case the inset is just a crop of the central region of the sketch to capture the detail lost in file compression necessary to meet the board's image size requirements.
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Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs
CN Sketch Gallery
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Ares
member
Reged: 03/03/07
Posts: 89
Loc: Krakow, Poland
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Outstanding comet sketch. For sure the best I've seen...
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-Ares-
8" f/4 Newtonian
Orion SVP mount
Obs.loc.: 50.2°N 19.8°E
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rodelaet
Carpal Tunnel
Reged: 04/28/06
Posts: 2655
Loc: 50°56' N - 4°58' E (Belgium)
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Eric, The fact that you're sketching again is excellent news.
The sketch itself is a brilliant piece of work.
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Rony
My Astronomy Sketches
My Binocular Sketches
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cildarith
Carpal Tunnel
Reged: 08/26/04
Posts: 2122
Loc: San Diego, CA
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Thanks for your comments, Ares and Rony!
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Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs
CN Sketch Gallery
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frank5817
Post Laureate
Reged: 06/13/06
Posts: 3045
Loc: Illinois
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Eric,
Beautiful sketch of the current comet. Excellent work on the details and color. I'm probably getting a better look at this comet through sketching here at the Forum than I would have seen at my eyepiece. Glad to hear the fires are not being fanned by the winds as they were and you are out of harms way. I have relatives in Ramona and they are keeping me posted.
Frank
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novbabies
Postmaster
Reged: 06/05/05
Posts: 15678
Loc: Northern Georgia!
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Eric, great sketches! Your close up with the three extensions makes me long for access to my scope (it's in CT, I'm in GA), but thnakful that I had the foresight to at least bring my 7x35 binocs. What an amazing spectacle we are priveleged to be seeing !!!
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Good Seeing!
Mark
Orion 12" XTi f/4.9
VERY old Edmund 6" f/8 reflector
Assorted binoculars
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CarlosEH
Post Laureate
Reged: 01/19/05
Posts: 3115
Loc: Pembroke Pines, Broward County...
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Eric,
A fantastic observation of this very interesting comet and it's unique jets and coma. Your renderings at low and high power show this very well. We are all glad to see you observing after your local disaster. The best of luck in your recovery.
Carlos
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Achernar
Post Laureate
Reged: 02/25/06
Posts: 3721
Loc: Alabama, USA
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Nice rendition of Comet Holmes. The yellow color I saw matches your drawings perfectly. It seems you had better seeing than I did last night, given the close up of the nuclear jets.
Taras
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10-inch F/4.5 Discovery Dob
6-inch F/8 Homebuilt Dob
4 1/4-inch F/4 Homebuilt reflector
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Special Ed
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Reged: 05/18/03
Posts: 3531
Loc: Greenbrier Co., WV 38N, 80W
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Eric,
Excellent rendering of your detailed observation.  I believe that one reason why 17P/Holmes has such an unusual appearance is because we are between the comet and the Sun so much of the material is streaming almost directly away from us. The comet is high above the ecliptic and we aren't exactly between it and the Sun,so we can see partly behind it. That might account for the fan-shaped coma. See the orbit simulated here. Just put P/Holmes in the search window.
PS I just noticed what filter you were using.
Edited by Special Ed (10/28/07 01:08 PM)
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WadeVC
Carpal Tunnel
Reged: 12/02/05
Posts: 2799
Loc: Lodi, California,
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Quote:
PS I just noticed what filter you were using.
Yeah. Thank goodness its not one I hope to add to my collection anytime soon...and one I'm sure Eric would love to get rid of as well.
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Orion XTi10 f/4.7
Orion XTi8 f/5.9
Meade NGC 70mm f/10
Orion UltraView 10x50 Wide-Angle Binoculars
My Sketch Gallery
My Astronomy Blog
A wise man can see more from the bottom of a well than a fool can from a mountain top.
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cildarith
Carpal Tunnel
Reged: 08/26/04
Posts: 2122
Loc: San Diego, CA
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Thanks for your comments one and all!
I was clouded out Friday night, but last night was very clear:
17P/Holmes
Periodic Comet
Parks Astrolight EQ6 • 6" f/6 Newtonian Reflector
7.5mm Parks Gold Series Plössl • 120x, 26' Field of View
28 October 2007 • 05:55-06:45 UT
Here is my second observation of the outburst of periodic comet 17P/Holmes. It is still easily visible to the unaided eye, but seems to have dimmed slightly. Its size has increased considerably and is now clearly non-stellar, appearing as a small circular puff of nebulosity in both the 6x30 finder and the 10x50 binoculars.
The envelope of dust surrounding Comet 17P/Holmes has expanded considerably in the 44 hours since my previous observation of this spectacular outburst. I estimate its apparent angular diameter as about 8', nearly double the size seen in the previous sketch. Though much larger, the comet also seems slightly dimmer; the strong yellow color has also abated somewhat and the hue is now very pale.
The pseudo-nucleus remains a stellar point, even at high magnifications, but it now seems to have become increasing shrouded by the dust that has been emitted. A bright fan of material extends in a roughly southward direction from the pseudo-nucleus to the perimeter of the still almost perfectly circular coma. Faint streamers curve northeastward on either side of this fan like the appendages of a ghostly scarab. A semicircle of darkness wraps halfway around the core on the northeast side.
Near the pseudo-nucleus, two prominent but diffuse streamers dominate the bright fan of ejected dust, one extending due south, and the other south-southwest. A prominent knot is visible intermittently in the SSW streamer, very close to the pseudo-nucleus.
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Eric
6" f/6 Parks Newtonian
10x50 Bushnell Binocs
CN Sketch Gallery
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WadeVC
Carpal Tunnel
Reged: 12/02/05
Posts: 2799
Loc: Lodi, California,
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Another great report and sketch to follow it up Eric.
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Orion XTi10 f/4.7
Orion XTi8 f/5.9
Meade NGC 70mm f/10
Orion UltraView 10x50 Wide-Angle Binoculars
My Sketch Gallery
My Astronomy Blog
A wise man can see more from the bottom of a well than a fool can from a mountain top.
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frank5817
Post Laureate
Reged: 06/13/06
Posts: 3045
Loc: Illinois
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Eric,
Excellent additional sketch from last night.  I looked for streamers and subtle texture but no luck. I think it was the poor seeing or maybe my older eyes or both. I'll need to try again tonight.
Frank
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rolandlinda3
Carpal Tunnel
Reged: 01/24/06
Posts: 1622
Loc: Crozet VA 22932
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Both sketches are really nice. It is so good to see sketch detail. I have friends running to see it through scopes, but I know without studying and sketching it, they won't see half of what you have captured. Roland
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CarlosEH
Post Laureate
Reged: 01/19/05
Posts: 3115
Loc: Pembroke Pines, Broward County...
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Eric,
Another outstanding observation of this very interesting "hairy star." The jets and coma continue to be prominent. I hope to observe this comet soon myself.
Carlos
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Dee
professor emeritus
Reged: 03/12/06
Posts: 646
Loc: Ireland
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Very interesting second report, you know your comets, fantastic sketch that eyepiece must be outstanding !!!
Your skills in observing are to be applauded.
Dee
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