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View Full Version : Comet 17/P Holmes in outburst



The Bad Astronomer
2007-Oct-25, 02:02 AM
I just took several shots of Comet 17/P Holmes which is currently in outburst. It's easily 3rd mag, if not brighter. I posted the images on my blog (http://www.badastronomy.com/bablog/2007/10/24/comet-holmes-wow/).

Here is one of it with Cassiopeia. The contrast could be better, but it's there! Unfortunately, the Moon is nearly full, so contrast is an issue. Go to the blog post for better contrast images.

VoijaRisa
2007-Oct-25, 04:44 AM
I managed to find it in my 8" SCT (once I got my finder realigned :doh:).

I don't have my SLR with me and my power cord is MIA too, so I just tried to snap a shot of it holding the camera up to the eyepiece. I got a few decent images representative of what I saw in the eyepiece. Here's the best of 'em.

BBigJ
2007-Oct-25, 05:50 AM
Thanks VR, you just saved my the trouble of dragging my 10" dob out into the street. I wouldn't see anything better than that in my light polluted Bay Area sky.

RickJ
2007-Oct-25, 06:08 AM
Here's my version. Dang thing was so bright I had to use 0.5 second sub exposures or my non blooming camera BLOOMED on the core of this guy. That's bright. This is 11 half second shots plus 4 one second shots in each RGB color. Taken through clouds that soon shut me down. How bright is this guy?

This guy is currently about 2.45 AU out there and it is receding. That would put it in the asteroid belt. So did it get belted? Sorry. I know it's done this before so likely it's own doing but still you have to wonder.

14" LX200R

Rick

winensky
2007-Oct-25, 12:18 PM
Thanks everyone and especially Rick, best pic I've seen yet. The blasted thing sits on my north east horizon so keep posting guys!

Kind regards
Matt

jpstanley
2007-Oct-25, 01:23 PM
Not sure where the green came from, but here's my photo.

VoijaRisa
2007-Oct-25, 02:11 PM
Nice shot jp.

I'm again struck by how symmetric the halo appears to be. Through my 8" it looked nearly perfectly round with a tiny bit of extention that I attributed more to reflection in the eyepiece than any natural extention.

This seems rather odd to me. Outgassings wouldn't be so symmetric from what I understand. Sure they can redistribute themselves, but that much this quickly?! The same for some sort of collision. Makes me wonder...

Seeing your images that confirm that nice symmetric halo only confuses me more.

wayback
2007-Oct-25, 02:23 PM
I'm again struck by how symmetric the halo appears to be.

Indeed - it seems like that on all the pictures. Is there a known projectory of the comet?

btw: great pictures!

RickJ
2007-Oct-25, 05:03 PM
4 hours after I took the image posted earlier in this thread I tried again when the clouds opened a hole. I used 1x1 binning for 0.5" per pixel resolution. Clouds only opened long enough for a black and white shot. Boy has it changed in those 4 hours. Now there's a ring that was only hinted at in the earlier image and it is off center the opposite direction. This guy seems to be making symetrical outbursts. For some reason, when converted to JPEG the nucleus goes from a near point to a blob that runs down and to the right (southwest). There's a bright jet in that position on the 16 bit tiff. I can't seem to get the JPEG to work right. The compression in Photoshop seems not to understand comets and I'm due to hit the road in 20 mintues so no time to figure it out.

Taken at 6:40 UT Oct 25, 2007

Rick

The Bad Astronomer
2007-Oct-26, 08:24 PM
I took some shots last night through my 12.5" using the camera mounted on a tripod. Only a couple turned out looking like what the eyepiece view was. Here's one. The yellow color by eye was amazing. Must be lots of dust in the outgassing.

Noclevername
2007-Oct-27, 01:03 AM
Hmm, looks like a dandelion puff!

Tucson_Tim
2007-Oct-27, 02:07 AM
Great pictures. Keep them coming . . .

JAICOA
2007-Oct-27, 02:07 AM
Lots of great photos here, You all did great guys Welldone!

mirceaar
2007-Oct-27, 01:20 PM
I managed to get this pic under a nasty sky filled with haze. And the vewy vewy ugly full moon.

Moseley
2007-Oct-27, 01:31 PM
Welcome to the new members with their excellent pics.

Thanks for all the great pics guys.

france113
2007-Oct-28, 02:19 AM
hey guys.
i got this 40mm telescope( i know its not powerful), so im wondering if it is possible for me to see it?

Tucson_Tim
2007-Oct-28, 02:22 AM
I managed to get this pic under a nasty sky filled with haze. And the vewy vewy ugly full moon.

That's a great picture!

Tucson_Tim
2007-Oct-28, 02:28 AM
hey guys.
i got this 40mm telescope( i know its not powerful), so im wondering if it is possible for me to see it?

It's a naked-eye object at approx magnitude +2.5. so you'll be able to see it just fine. Depending on the quality/focal length of your scope you should be able to get a solid 10x magnification. You won't see a lot of detail - probably just a fuzzy dot. You won't see the image as large as the photos here that were taken with much larger scopes. You're also far enough north to get a good view. Go for it - you've got nothing to lose by trying. Let us know what you see . . .

ngc3314
2007-Oct-28, 03:53 AM
Just watch it grow! This set of images is displayed in matching logarithmic scales, and taken 20 hours apart today. To first order, one expects the total brightness to be constant, and the surface brightness to drop as the square of the linear expansion factor (as long as the dust particles stay the same). To my eye, it was distinctly fuzzy with the naked eye tonight, but not particularly less prominent overall than last night.

I am struck that the offset of the brightest diffuse region from the apparent nucleus is more or less perpendicular to the project orbital motion (which is nearly to the right in these images). This is not to suggest that I have any profound idea as to what that means. However, I am now convinced that the ringlike structures are real, even without having a chance to do any detailed image modelling or filtering...

fogged in
2007-Oct-28, 04:39 AM
Just watch it grow! This set of images is displayed in matching logarithmic scales, and taken 20 hours apart today. To first order, one expects the total brightness to be constant, and the surface brightness to drop as the square of the linear expansion factor (as long as the dust particles stay the same). To my eye, it was distinctly fuzzy with the naked eye tonight, but not particularly less prominent overall than last night.

I am struck that the offset of the brightest diffuse region from the apparent nucleus is more or less perpendicular to the project orbital motion (which is nearly to the right in these images). This is not to suggest that I have any profound idea as to what that means. However, I am now convinced that the ringlike structures are real, even without having a chance to do any detailed image modelling or filtering...
With that much increase in less than one day, is the magnitude still considered 2.5 ?
I can see it with my naked eyes even with the moon in the sky. It's pretty clear here on the coast tonight. Like someone said earlier......... looks kind of like a dandelion with my 8 power binoculars.

Romanus
2007-Oct-28, 06:14 AM
I just saw 17/P tonight...she is BEAUTIFUL. Very bright--easily visible with moderate light pollution and a nearly full Moon, and the declination could not be more favorable at this time of year. Though I'm no expert in guessing magnitudes, it looks nearly as bright as Alpha Persei itself, which would peg it at solid second mag. Beautiful in 10x50s, and impressive even in my 60mm at 30x; very symmetrical coma, with a noticeably off-center brightness at its nucleus. If my eyes don't deceive me, I even saw hints of shell structure myself.

An astronomical treat all around, and my first periodic comet. :)

france113
2007-Oct-28, 07:13 AM
it is kinda hard for me to spot stuff like that, but i think i got it. thers a bright sorta red object in the sky, its north east of the moon from where im looking. is it the comet, mars or a star? :confused:

actually its 50x 450mm

mirceaar
2007-Oct-29, 09:13 AM
If it's really bright and reddish that would be Mars.
You can get directions to the comet on this map here (http://www.spaceweather.com/images2007/24oct07/skymap_north_holmes.gif?PHPSESSID=pricqj10veoqe8t8 cc6qs6kuk6).
If you got clear skies, you'll be able to spot it w/ naked eyes.

That's a great picture!
Thanks, Tim.
Now I'm watching it grow on the 'net, 'cause the sky here's been anything but clear and there's no clear night in sight this week. Grr.

france113
2007-Oct-30, 05:26 AM
i spotted the red object in north east, that might even be the comet. i want to do it today too :)
thanx for the map!

jt-3d
2007-Oct-30, 06:59 AM
i spotted the red object in north east, that might even be the comet. i want to do it today too :)
thanx for the map!

That might just be Mars. It's pretty close to the moon right now. I think you need to look more north. I looked at it tonight through my 7x35 binoculars and if you see it, you will know what it is. I think you said you're using binoculars. If you're in doubt, keep looking because that's most likely not it.

Not to sell Mars short but it's not going anywhere. Holmes is. :)

agingjb
2007-Oct-30, 07:24 PM
Finally picked out the comet. It's a naked eye "star", thirdish I'd say, obviously not a star in binoculars. Seeing isn't wonderful BTW; M31 (fairly close) wasn't that easy.

mirceaar
2007-Nov-02, 12:44 AM
I'm back after just one clear night to take a shot at 17P.:p

Tucson_Tim
2007-Nov-02, 12:50 AM
I'm back after just one clear night to take a shot at 17P.:p

Big difference after four days!

Kootenaistar
2007-Nov-02, 07:16 AM
Don't have my own scope, but even naked eye I managed to get it after a computer check on a sky map and binos. Also, here's a tidbit discussed with a friend who does have a good scope and belongs to our astro club. ANY comet will travel with it's tail (if there is one) pointing directly AWAY from the sun. The way it sits now, after its orbit of the sun awhile ago, it is almost directly opposed to the sun from where we see it. Therefore, could not that somewhat brighter "pie slice" be the tail showing through :think:

NGCHunter
2007-Nov-02, 04:20 PM
Here's the only shot I've been able to get of it in clear weather so far (though clouds still rolled in early leaving me with only a few frames to stack). Taken on 10/31. It's a stack of 3x15 second exposures with a Sony DSC-F828 looking through a 40mm eyepiece on an 8" LX200.

mirceaar
2007-Nov-03, 02:00 AM
And the show goes on :)

mirceaar
2007-Nov-03, 11:09 PM
And one more, I'd say more life-like.

Tucson_Tim
2007-Nov-03, 11:14 PM
And one more, I'd say more life-like.

It's not so spherical anymore. Thanks for posting.

winensky
2007-Nov-04, 10:03 AM
True, our orbits are diverging and we are begining to see the gas and dust trail more 'edge on'.

Kind regards
Matt

Slobodan
2007-Nov-04, 10:35 PM
Since comet 17/P Holmes is now considered to be a "life time astronomical event" among astronomers why we still don't see any pictures of the comet from the world's biggest telescopes? Is it just because they have schedules which can not be changed even if there is a "life time event" under way?

JAICOA
2007-Nov-06, 08:26 PM
I concur with the question. there seems to be no interest to nasa and other large based obervatorys there leaving it to us i guess the Amateurs.

Urbane Guerrilla
2007-Nov-12, 05:46 AM
Found Holmes on the second glance in the very early hours of 11/11/07, right there in Perseus. France, find Mirfak, the "fork star" in Perseus' Greek-lambda shape and the transparent lit-up disc of the comet should be in your binoculars' field of view. After finding Mirfak, find Delta Persei. It's even nearer that one.

Yep, still naked-eye. Ridiculously easy in binoculars, but looking with naked eye, you can pick it up well with averted vision.

Urbane Guerrilla
2007-Nov-13, 03:45 AM
Actually, it's nearer Mirfak than Delta Pers. Sorry 'bout that. Took a look predawn with Perseus high in the NW, about 1315 UT. Just a big round thing in 7 x 50s, naked eye visible even with the east just beginning to lighten.

Tucson_Tim
2007-Nov-13, 01:24 PM
Actually, it's nearer Mirfak than Delta Pers. Sorry 'bout that. Took a look predawn with Perseus high in the NW, about 1315 UT. Just a big round thing in 7 x 50s, naked eye visible even with the east just beginning to lighten.

When the comet first outburst it was much closer to Delta Persei. Just a few days ago it was equidistant from both Alpha and Delta. Now it is closer to Alpha Persei and closing in. Check out this thread for position projections:

http://www.bautforum.com/astronomical-observing-equipment-accessories/66491-will-17p-holmes-occult-alpha-persei-mirfak-alcheb.html

Urbane Guerrilla
2007-Nov-30, 08:52 AM
Thanks, Tim. How are things at the U of A -- my alma mater, or as near as I come to one? I took frosh astronomy there to satisfy the science requirement, as I'd picked UA for its Slavic Languages Department, and was quite bitten by the astro bug.

NGCHunter
2007-Nov-30, 04:36 PM
Since comet 17/P Holmes is now considered to be a "life time astronomical event" among astronomers why we still don't see any pictures of the comet from the world's biggest telescopes? Is it just because they have schedules which can not be changed even if there is a "life time event" under way?

Hubble did take a picture of the nucleus at the beginning of this month.
http://bp2.blogger.com/_FgKwPBKWZpo/Rz1wuqS5iYI/AAAAAAAAAS0/u1O3FneOeY8/s320/Holmes_from_Hubble.jpg
Apparently the coma is now bigger than the sun... that's mind boggling when you think about it.

ngc3314
2007-Dec-01, 04:13 AM
Since comet 17/P Holmes is now considered to be a "life time astronomical event" among astronomers why we still don't see any pictures of the comet from the world's biggest telescopes? Is it just because they have schedules which can not be changed even if there is a "life time event" under way?

There is a nice image from a widefield mosaic camera at the 3.6-meter Canada-France-Hawaii telescope here (http://apod.nasa.gov/apod/ap071121.html). among other places. There may be more not getting wide release. By now, the comet is so big that few large telescopes have wide-enough field imagers to take it in without a major mapping project (come to think of it, last time I imaged it with our campus 0.4m telescope, it took me 12 frames). Best I can remember, the Gemini telescopes don't take in much more than 5 arcminute fields, with Subaru's SuprimeCam the giant-telescope champion at something like 3/4 degree. On top of that, it would take something even more amazing (like SN 1987A) to chase all the star and galaxy people off the telescopes with their carefully prepared schedules of multiobject spectroscopy. For something this bright, large telescopes haven't offered too much unique in the way of imaging; IR spectroscopy would be a powerful approach, though. {Truth in advertising - I did get bumped from the schedule of the ESO 3.6m by SN 1987A several months after its explosion was observed. I happend to check somewhat later and found that it was snowing for most of those nights anyway...] Also, keep in mind that not all facilities feel much urge to release pictures quickly for public edification, depending on their user communities...