BABloggee Dan Fischer emailed me to say that comet 17P/Holmes has brightened incredibly, from magnitude 17 to magnitude 3 literally overnight. That’s a brightening of a factor of 400,000!
It’s incredible, and it appears to be legit (see also here). The comet is in the constellation Perseus, and is about 4 degrees from the bright star Mirfak.
I will go out and check this tonight for sure! To see for yourself, first, be in the northern hemisphere. 
Then around 8:00 local time face northeast. See the big W on its side, facing left? That’s Cassiopeia. Below is the star Mirfak (if you keep looking lower, near the horizon, you’ll see the far brighter yellow star Capella). The comet is just below and to the left of Mirfak, and the star is about 3 or 4 times brighter than the comet is supposed to be — unless the comet gets even brighter or fades away. The comet should be easily visible and fuzzy-looking in binoculars.
You can find online sky maps at Your Sky and Heavens Above that can help you.
Sometimes comets can brighten a lot if they break up a bit when they are near the Sun, exposing previously buried reservoirs of ice which then sublimate and are lit up by the Sun. If this is what happened, we need as many observations of it as possible to nail down the brightness. Given that Comet Holmes is over 220 million miles from the Sun and 150 million miles from the Earth, this is very impressive indeed.
If you get pictures, post them on BAUT!
October 24th, 2007 at 2:56 pm
yea! I seen it on Spaceweather just a hour ago!
Skies please stay clear. Be good. BE COOL!
October 24th, 2007 at 3:04 pm
T-minus 7 hours before someone claims that it’s a spaceship firing up its drive or some such.
I’m taking bets on the over/under
October 24th, 2007 at 3:19 pm
I’m certainly going out to take a look, and I hope I see it, as it will be a milestone moment for me. If I see it, it will make the 50th comet I’ve observed in my astro-lifetime.
October 24th, 2007 at 3:21 pm
Cool, I’ll try to take a look tonight!
October 24th, 2007 at 3:32 pm
Yup, it’s cloudy out: proof positive that something of astronomical interest is going on.
October 24th, 2007 at 3:38 pm
Comet Holmes? “Elementary.” I’ll be looking tonight. (:
October 24th, 2007 at 3:49 pm
Stupid Southern Hemisphere! Stupid stupid stupid Southern Hemisphere!!
October 24th, 2007 at 3:53 pm
I sure hope it clears up tonight, I really want to go look, alas I think I will miss out…..darn this Alberta Weather.
October 24th, 2007 at 4:03 pm
Too bad. I hurried out the minute I read this — only to find that it’s completely overcast.
October 24th, 2007 at 4:13 pm
So we get no rain on the East Coast for weeks, and soon as a comet shows up….
How long should it be visible? A few days at least?
October 24th, 2007 at 4:39 pm
Thanks for the head’s up, Phil! Of course, I had to live in So Cal, so I’ll be hoping the smoke clears up enough to see it.
October 24th, 2007 at 4:53 pm
Well, i’m bad luck. As soon as some cool astronomical event happens, it just has to be cloudy here in Poland (light pollution from nearby Szczecin doesn’t help too)
October 24th, 2007 at 4:53 pm
Did I mention that I hate clouds?
Of course my baby apple trees are happy…
Rich
October 24th, 2007 at 5:04 pm
Sometimes, I just HATE Florida weather. It clouded up completely today, so I have ZERO chance of seeing this event.
Hope you have better views, Phil.
October 24th, 2007 at 5:09 pm
Wow I wonder if the appearance of comets has an effect on cloud cover…..
October 24th, 2007 at 5:18 pm
I would try to see it, if only my entire world weren’t engulfed in ash.
October 24th, 2007 at 5:32 pm
I’ll be out tonight as long as it stays as gorgeous as it is right now.
October 24th, 2007 at 5:37 pm
[...] and Bad Astronomy have more [...]
October 24th, 2007 at 6:10 pm
I seen it! Wow, you really can’t miss it! I thought it was a star at first though, until I got sick of it and took my scope out and see!
October 24th, 2007 at 6:16 pm
Eh, cloudy in NW Florida. Dang.
October 24th, 2007 at 6:21 pm
Saw it here from Michigan as well. No problem naked eye.
Last thing I heard it was brighter than 3rd magnitude.
October 24th, 2007 at 6:31 pm
Still cloudy here. Double dang. But camera is on the tripod, battery is charged and remote is attached, so if those clouds part…..
October 24th, 2007 at 6:47 pm
Waiting for someone to say “rushed out to see the comet, then realized it was daytime”.
October 24th, 2007 at 7:00 pm
19:45 CDT (00:45 ut) Clear in chicago, sme small clouds. Looked all over indicated area with 7X35′s, didn’t see anything comet-like. Too many trees and streetlights? Will try again
October 24th, 2007 at 7:09 pm
…and the cloud cover thickens. Frustrating, frustrating, frustrating. My view of the sky to the NE is beautiful. No light pollution at all, to speak of. Did I mention “frustrating?”
October 24th, 2007 at 7:13 pm
Saw it in Denver, but the sky’s so bright that it doesn’t look like much. Maybe it’ll improve as sunset fades (though the near-full moon isn’t helping matters). Naked-eye it just looks like a star. In binos you can see it’s non-pointlike and doesn’t twinkle, but I can’t get any faint “fuzz” around it. Will try again later!
October 24th, 2007 at 7:24 pm
Saw it in KC. A little faint from all the light pollution, but still awesome.
October 24th, 2007 at 7:38 pm
20:15 CDT (01:15 UT) Went back out after checking star chart again. Realized that one “star” had disc. Dragged out 8″ f5 not-so-hot homebuilt telescope. Creamy-white blob, no halo or tail visible.
HOT-DIGGITY-DAWG!! Thanks Phil!!
Chas, from Amazing Adventure 2
October 24th, 2007 at 7:45 pm
Times like this I know I need a decent telescope. I think I scoped it out with my binocs but not 100% sure. I know I was looking in the right spot. Well, The Moon was impossibly bright tonight, and very nice to look at as well.
October 24th, 2007 at 7:50 pm
Got it! At 8:45 CDT from the back yard with my 10x50s. Looks to me about the same magnitude as Del Perseus (3) Difficult with some *very* thin clouds and a very bright moon.
Thanks for the heads up.
October 24th, 2007 at 8:40 pm
Yeah, there’s still no halo that I can see, but it’s definitely roundish. Not spectacular, but pretty damn cool nonetheless.
October 24th, 2007 at 8:49 pm
In my 8 inch dob, it looks like a brighter elliptical galaxy than I’ve ever seen–bright center with not-quite perfectly round halo. I kept thinking I was having focusing problems until I realized that oh, the halo will never be crisper than that. in 9x finder, distinctly yellow. Naked eye, it seemed brighter than Mirfak, which was more dimmed by light pollution. I’m not yet very good at determining magnitudes, but I’d guess brighter than 3.0
October 24th, 2007 at 9:25 pm
It won’t move much from night to night now since it’s already been round the sun and is on it’s way back to the outer solar system. It was near the sun about the same time McNaught was dazzling us in both hemispheres at once.
I hope it remains bright for a couple more nights. If it isn’t the clouds it’s the dang waxing moon…
October 24th, 2007 at 9:53 pm
In my 11×80 binos it is very bright and compact golden yellow at about mag 2.5; it also appears distinctly out-of-round, like a tiny but extremely brilliant elliptical galaxy, with the long-axis apparently in line with the sun. I just talked to a colleague a few hundred miles from me here (i’m in rural Wisconsin) who has a 20-inch dob trained on it and he thinks he’s begun to see evidence of a tail at high magnification.
If I had come across Perseus this evening without knowing what was going on, I would have declared, “What the heck is THAT doing there???” and immediately assumed it to be a nova. Just spectacular!
This is a whopping increase in brightness for a comet so far from the Sun. One wonders if it got knocked by a small asteroid out in the asteroid belt where it is…perhaps the Hubble or other large telescope may be able to discern the signature of a debris fan like that which the Deep Impact probe produced on Tempel 1.
October 24th, 2007 at 10:05 pm
Come to think of it, when I looked at it thru my big binocs, it did look a bit like Saturn– not round, but elongated. Nuts. Now I’m dying to see decent deep CCD images!
October 24th, 2007 at 10:08 pm
Bleah… totally overcast here.
October 25th, 2007 at 1:30 am
I saw this tonight through a large Dobsonian scope about 15″, it looked great. You could not see a tail since the sun is opposite the comet in the celestial sphere thus the tail points away from us. But you could certainly see the nucleus and the gases around it. I saw it from N. Texas DFW area at about 02:00 UT. Fantastic!
October 25th, 2007 at 3:35 am
I got a look at this last night. Spectacular! An extra ‘star’ has literally just sprung up out of of nowhere in Perseus!
I wrote a more thurough observation log on my blog: http://www.bartbusschots.ie/blog/?p=561
Is’t astronomy fantastic, you just never know what you’re gonna see!
Bart.
October 25th, 2007 at 7:43 am
In the literature I read, this is what happens when they start up their fusion torches in preparation for Earth orbiting and takeover.
Oh, you study astronomy literature along with the sci-fi? Well then, would this comet become a prime target to fetch some of a comets juicy innards for free?
October 25th, 2007 at 7:49 am
Oh I’m so excited to see pictures, maybe it will be clear tonight, I am taking the scope out as soon as I get home!
October 25th, 2007 at 8:20 am
[...] seems to be crashing and burning like other famous things you know, has just become super-bright people say you can actually see it without those huge telescopes! We’re not kidding! See it here! And [...]
October 25th, 2007 at 8:49 am
I ran out and saw it this morning at 6 am in Southern Oregon and it was so bright! I cannot wait to see it again tonight.
October 25th, 2007 at 10:56 am
Saw it with my wife and kids last night from California- with the unaided eye it looks just like a ~2.5 magnitude anomalous “star” in Perseus, until you observe with binoculars (we used 7x50s) and it looks round, but extended (not fuzzy). I turned my scope to observe in more detail and it looks very spectacular. In appearance it looks similar to those 8th or 9th magnitude comets, but much much brighter! The nucleus is quite bright, and the coma is well extended and looks round at first, but it’s actually slightly elliptical. Can’t wait to see what it looks like tonight.
October 25th, 2007 at 12:26 pm
RATS! the smoke from the So Cal fires is heading my way as we speak! I’m hoping for a slight wind shift for tonight.
October 25th, 2007 at 1:30 pm
Thanks for the heads up…would have missed it otherwise.
October 25th, 2007 at 3:20 pm
[...] (here), as well as further links to information sources and another post on locating the object here, and some of his pictures [...]
October 25th, 2007 at 9:04 pm
Great object, the color is yellow green big fuzz ball in 10×50′s at 10 pm from Boston area. Go Red Sox!!
October 26th, 2007 at 6:11 am
The skies over upstate N.Y. cleared lastnight….Even with the big, bright moon…there it was…a fuzzy in all its glory!
October 26th, 2007 at 9:19 am
True, visible naked-eye even in full moon! with 90mm meade etx, its a fuzzy ball, very big, bigger than what jupiter is seen.
[is the tail forming there?]
October 26th, 2007 at 12:44 pm
WOW!
October 28th, 2007 at 8:14 pm
[...] does not look ‘Perseus’ familiar to us due to the bright stellar object now.” Spaceweather and Bad Astronomy have more details. Thanks to BAUT member Keith G for the photograph. Here’s a link to the forum [...]
October 29th, 2007 at 3:09 pm
29 OCT 07 PM
Phil and all,
As the song goes, “…and the skies are not cloudy all day.” (night too) so the seeing should be good tonight in SW Oz. I’ll take the old Dobsonian out tonight for a look see before Moon rise, and report back tomorrow. I can turn off the security lights out here on the farm and light pollutin’ Dodge City is 30 miles away so no problem.
Thanks!,
Jim Oss, hobbiest astronomer and amateur radio operator (AA0PP)
homeontherangesunflowers@yahoo.com
Jetmore, Kansas
October 30th, 2007 at 7:11 pm
i just saw it here in east tn and it was amazing. you could see it with the naked eye but you could see it really good with a pair of bionaculers
November 6th, 2007 at 12:55 am
I have taken a few timelapse movies of the comet over the past few days and am out every night that i can until its not visible anymore. its easy to get photos of this one.
check them out here:
http://www.revver.com/playlist/show/291594/
thomas
November 6th, 2007 at 5:55 am
Cool, 400 000x is a lot
November 15th, 2007 at 1:38 am
We saw it last night (early morning actually) over Ojai, California. Clear skies – Awsome!