IPB

Welcome Guest ( Log In | Register )

The Great Christmas Comet of 2011, 2011 W3 (Lovejoy)
Guest_Sunspot_*
post Dec 2 2011, 09:59 PM
Post #1





Guests






http://sungrazer.nrl.navy.mil/index.php?p=.../birthday_comet

Possible very bright sungrazing comet coming mid December - Comet Lovejoy C/2011 W3 (Lovejoy)

Information in the link above.
Go to the top of the page
 
+Quote Post
 
Start new topic
Replies
Mongo
post Dec 21 2011, 12:52 AM
Post #2


Member
***

Group: Members
Posts: 723
Joined: 13-June 04
Member No.: 82



From comet-ml post #18958:

QUOTE
Hi all,

When I first looked out this morning (from Cowra in central NSW) and saw the layers of high and middle-level cloud, I almost went back to bed. But after a few minutes deciding, I set up the 25x100 binocular telescope and started to sweep along the horizon which, surprisingly, was clear for the first two or three degrees. At 4.20 local summer time (1720 UT) I noticed something like a distant searchlight beam rising over the slope of a small hill which sports the rather grandiose name of "Porter's Mount". With the sky becoming bright, I could see a clear feature on the local horizon (a tree about two thirds of the way up the grassland slope of Porter's Mount) near where the beam emerged and, finding this without the telescope, I could then see about 2 - 3 degrees of tail rising up to a bank of heavy cloud. The tail must have been quite intense to be seen in such a bright sky and, from the calculated position of the head, at least 7 - 8 degrees long (although most of this was not seen. Neither was the head as the sky had become very bright by the time it would have cleared Porter's Mount).

On a slightly different topic, as one of the few Ikeya-Seki veterans in this group, it is probably timely to sound a warning not to give up on this comet because of the degree of fading that has obviously taken place. Back in 1965, the arrival of I-S at perihelion was surrounded by a lot of media hype. Predictions that a comet brighter than the Moon was coming, while they turned out to be technically true, failed to make clear that the comet would be only a few arcminutes from the Sun's limb at that time and would fade very rapidly afterwards. Of course, the general public missed much of the display at perihelion and dismissed the comet as a dud. On the day of perihelion, Fred Whipple called it "a scientist's comet"; one that was great for astronomers but a disappointment for the public. Unfortunately, the media dropped the subject (by and large) and when the "public" show occurred over a week later, only those who normally rose before dawn for work or other purposes saw it.

My first couple of views post perihelion were not all that exciting. High cloud always seemed to shroud the eastern horizon and by the time the comet cleared this, the sky was very bright and the comet looked washed out with only a small diffuse spot of a coma and a fading tail. Then, exactly 10 days after perihelion, there was a morning of exceptional clarity and by that time the comet was far enough from the Sun to be rising in a dark sky. The sight was magnificent. In the dark sky, the coma appeared brighter than the earlier twilight views and looked small and dense. As for the tail, this appeared (as John Bortle has written on several occasions to this group) "solid", not diaphanous like the tail of a normal comet. And there was little "normal" about Ikeya-Seki! Today, we would probably think of laser beams or Star-Wars light sabres ... but this was back in 1965!!

Now, I am certainly not saying that W3 will become as remotely spectacular as I-S, but the lessons of 1965 are worth noting. The comet may become faint, but the tail may well retain relatively high surface brightness for quite some time and be impressive in coming days as it pulls out from the twilight (and moonlight). Don't dismiss this comet just yet! There may still be surprises in store.

David


In response to this, John Bortle wrote in comet-ml post #18961:

QUOTE
David is absolutely correct. I anticipate that the spectacle is only likely to grow better with time as the tail moves out of the morning twilight. Keep in mind that the brightness of a sungrazer's dust tail seems to fade much more slowly than does that of the coma, following closer to a rate dictated by the inverse square law. Likewise, Comet Lovejoy's tail is more-or-less still approaching Earth as the comet retreats from the Sun, slowing the fading process even further.

Go back and consult some of my earlier posts concerning the development of Comet Ikeya-Seki's post-T dust tail. Such may well foreshadow the sort of evolutionary path that the tail of Comet Lovejoy may see in days to come on a somewhat more modest scale.

Folks, be assured that the show isn't over yet by any means.

J.Bortle
Go to the top of the page
 
+Quote Post

Posts in this topic
- Sunspot   The Great Christmas Comet of 2011   Dec 2 2011, 09:59 PM
- - Sunspot   Here it comes http://sohowww.nascom.nasa.gov//dat...   Dec 14 2011, 09:22 AM
- - titanicrivers   And check out the SOHO Movie Theater! Choose ...   Dec 15 2011, 04:14 AM
|- - SteveM   QUOTE (titanicrivers @ Dec 14 2011, 11:14...   Dec 17 2011, 03:39 AM
- - Mongo   Spaceweather COMET LOVEJOY UPDATE: Matthew Knigh...   Dec 15 2011, 07:59 PM
|- - stevesliva   QUOTE (Mongo @ Dec 15 2011, 03:59 PM) If ...   Dec 15 2011, 08:05 PM
- - Mongo   Same here. Right now it's overcast from horiz...   Dec 15 2011, 08:31 PM
- - Juramike   It lives! http://www.youtube.com/watch?featur...   Dec 16 2011, 02:06 AM
- - Mongo   Here is another video: http://sdoisgo.blogspot.co...   Dec 16 2011, 03:52 AM
- - Explorer1   That's one tough cookie.... Any estimate for h...   Dec 16 2011, 08:09 AM
- - jamescanvin   140,000 km (1.2 solar radii) above the surface   Dec 16 2011, 08:31 AM
|- - Mongo   QUOTE (jamescanvin @ Dec 16 2011, 08:31 A...   Dec 16 2011, 02:45 PM
- - Sunspot   Seems to have left it's tail behind. http:...   Dec 16 2011, 09:48 AM
|- - Toma B   QUOTE (Sunspot @ Dec 16 2011, 11:48 AM) S...   Dec 16 2011, 04:08 PM
- - Mongo   It is still very soon, but it appears that Comet L...   Dec 16 2011, 10:12 PM
- - Sunspot   The Ion tail has reappeared too.   Dec 16 2011, 10:47 PM
- - Mongo   Another movie: SOHO LASCO C3 This site only show...   Dec 17 2011, 03:29 AM
- - nprev   The next few days may prove interesting...and spec...   Dec 17 2011, 03:34 AM
- - Sunspot   Visual sightings starting to come in now.   Dec 17 2011, 01:10 PM
- - Floyd   Why is the view better from south of the Equater? ...   Dec 17 2011, 02:31 PM
- - Mongo   Comet Lovejoy is no longer a daylight comet, so da...   Dec 17 2011, 02:58 PM
- - Floyd   Thanks Mongo, great explanation!   Dec 17 2011, 06:00 PM
- - MaG   Our friends took image from Argentina today mornin...   Dec 17 2011, 08:46 PM
- - Mongo   This was posted today by highly respected astronom...   Dec 18 2011, 10:30 PM
- - nprev   ...if John Bortle says anything about comets, I be...   Dec 18 2011, 10:34 PM
- - Stu   Wow. Ok, now I really am officially northern hemi...   Dec 18 2011, 10:48 PM
|- - scalbers   QUOTE (Stu @ Dec 18 2011, 10:48 PM) Wow. ...   Dec 18 2011, 11:33 PM
- - nprev   Now, now, Stu...we had Hale-Bopp! But, yea...   Dec 18 2011, 10:55 PM
- - Mongo   Report of a daylight sighting of Comet Lovejoy on ...   Dec 19 2011, 12:21 AM
- - nprev   Wow. Mongo, please keep feeding salient info like...   Dec 19 2011, 12:58 AM
- - Mongo   For those readers who are in the southern hemisphe...   Dec 19 2011, 02:15 AM
- - Mongo   From Malargue, Argentina this morning:   Dec 19 2011, 02:14 PM
- - Mongo   Finder chart for 35 degrees south on Wednesday mor...   Dec 19 2011, 08:44 PM
- - Stu   Tail sighted - and photographed - from Australia.....   Dec 19 2011, 09:30 PM
- - Mongo   This is interesting. From the comet-ml mailing li...   Dec 19 2011, 09:45 PM
- - nprev   Magnificent!!!   Dec 20 2011, 04:06 AM
- - machi   Amazing images, it's unbelievable, that this l...   Dec 20 2011, 10:06 AM
- - tasp   Impressive it withstood the tidal effects too.   Dec 20 2011, 02:06 PM
- - Mongo   Latest today from comet-ml mailing list: QUOTE Hi...   Dec 20 2011, 06:59 PM
|- - jamescanvin   QUOTE (Mongo @ Dec 20 2011, 06:59 PM) The...   Dec 20 2011, 09:45 PM
- - nprev   In moonlight, no less. Good grief.   Dec 20 2011, 07:45 PM
- - Mongo   Finder charts for 35 degrees South latitude on Thu...   Dec 20 2011, 08:40 PM
- - Mongo   Oh-oh. That title change may have been premature....   Dec 20 2011, 11:51 PM
- - Mongo   A photo from this post: QUOTE After reading Ian C...   Dec 21 2011, 12:27 AM
- - Mongo   From comet-ml post #18958: QUOTE Hi all, When I ...   Dec 21 2011, 12:52 AM
- - Mongo   From comet-ml post #18977: QUOTE Hi All, I have ...   Dec 21 2011, 05:06 PM
- - Mongo   From this Brazilian Portuguese-language blog:   Dec 21 2011, 05:09 PM
- - Mongo   From comet-ml post #18990 by Robert McNaught: QUO...   Dec 21 2011, 07:58 PM
- - Mongo   Here is a photo from this morning by outbackmanyep...   Dec 21 2011, 08:07 PM
- - Mongo   Photo from this site:   Dec 21 2011, 09:46 PM
|- - ugordan   Wow.   Dec 21 2011, 10:05 PM
- - scalbers   Very nice. Looks rather brighter than pieces of Mi...   Dec 21 2011, 11:06 PM
- - Mongo   There are some incredible movies now available fro...   Dec 22 2011, 12:07 AM
- - Mongo   The latest image of Comet Lovejoy, by Colin Legg. ...   Dec 22 2011, 03:11 PM
- - Stu   Good grief... view from the ISS... http://www.fli...   Dec 22 2011, 06:54 PM
- - Tesheiner   Wow!   Dec 22 2011, 07:20 PM
- - Stu   Lovejoy Rising...   Dec 22 2011, 08:44 PM
- - centsworth_II   This time lapse via a tip from Emily's Twitter...   Dec 22 2011, 09:08 PM
- - Stu   Just saw that, wish I'd noticed there were ear...   Dec 22 2011, 09:12 PM
- - Mongo   From comet-ml post #19028 by Dave Herald: QUOTE A...   Dec 22 2011, 10:48 PM
- - Mongo   Here is a cropped version of the full-resolution p...   Dec 22 2011, 10:53 PM
- - Mongo   I like this shot, taken by Jim Gifford, it is very...   Dec 22 2011, 10:58 PM
- - Mongo   From comet-ml post #19031 by David Seargent: QUOT...   Dec 23 2011, 12:35 AM
- - Mongo   A great photo by Lester Barnes of south Australia:   Dec 23 2011, 01:57 AM
- - Mongo   Commentary by John Bortle (comet-ml post #19037) o...   Dec 23 2011, 01:29 PM
- - Mongo   From comet-ml post #19038, replying to David Searg...   Dec 23 2011, 01:34 PM
- - Mongo   Another report on the comet by Geoff Dudley (comet...   Dec 23 2011, 01:42 PM
- - Mongo   Now that Lovejoy is "officially" a Great...   Dec 23 2011, 02:00 PM
- - Mongo   As expected, comet Lovejoy is growing more promine...   Dec 23 2011, 07:04 PM
- - Mongo   To make comparisons easier, I have put images of I...   Dec 23 2011, 07:15 PM
- - Mongo   The tail is getting bigger! From Rob Kaufman ...   Dec 23 2011, 07:21 PM
- - Mongo   From Robert McNaught, comet-ml post #19047: QUOTE...   Dec 23 2011, 10:42 PM
- - Mongo   More confirmation of today's observations, by ...   Dec 23 2011, 11:08 PM
- - Mongo   A response by Vello Tabur in comet-ml post #19055 ...   Dec 24 2011, 03:53 AM
- - elakdawalla   Mongo, I just want to say thanks for these summari...   Dec 24 2011, 04:03 PM
|- - ElkGroveDan   QUOTE (elakdawalla @ Dec 24 2011, 08:03 A...   Dec 24 2011, 04:13 PM
- - Explorer1   That would be rather tricky, considering the Darie...   Dec 24 2011, 06:46 PM
- - Mongo   Christmas Eve image of comet Lovejoy by Scott Alde...   Dec 24 2011, 07:42 PM
- - nprev   W O W ! ! !   Dec 25 2011, 01:36 AM
- - Mongo   Yes, I think that Lovejoy has done quite well for ...   Dec 25 2011, 02:08 AM
- - Mongo   From comet-ml post #19078 by David Seargent: QUOT...   Dec 25 2011, 02:55 PM
- - Mongo   From comet-ml post #19088 by Robert McNaught: QUO...   Dec 25 2011, 07:41 PM
- - Mongo   Comet-ml post #19096 by Rob Kaufman: QUOTE Here...   Dec 26 2011, 02:30 PM
- - Mongo   Comet-ml post #19100 bt Dave Herald, regarding the...   Dec 26 2011, 02:35 PM
- - Mongo   Comet-ml post #19101 by Rob Kaufman: QUOTE Hi Fra...   Dec 26 2011, 02:37 PM
- - Mongo   From comet-ml post #19115 by Jim Gifford: QUOTE A...   Dec 26 2011, 08:37 PM
- - Stu   Latest ISS shots put together...   Dec 26 2011, 09:07 PM
- - Mongo   From comet-ml post #19117 by Rob Kaufman: QUOTE N...   Dec 26 2011, 09:28 PM
- - Mongo   Comet-ml post #19119 by John Bortle: QUOTE --- In...   Dec 26 2011, 10:57 PM
- - Mongo   Comet-ml post #19122 by David Seargent QUOTE Hi a...   Dec 27 2011, 02:47 AM
- - Mongo   Comet-ml post #19122 by Vello Tabur QUOTE Hi, I ...   Dec 27 2011, 02:54 AM
- - Mongo   From comet-ml post #19128 by Michael Mattiazzo: Q...   Dec 27 2011, 05:49 PM
- - Mongo   A spectacular image hosted on Gary Kronk's Com...   Dec 27 2011, 08:02 PM
- - Mongo   Comet-ml post #19131 by Andrew Pearce: QUOTE Hi a...   Dec 29 2011, 02:00 AM
- - Mongo   Comet-ml post #19142 by Andrew Pearce QUOTE Hi Al...   Dec 29 2011, 11:02 PM
- - Mongo   Comet-ml post #19150 by Chris: QUOTE Hi all, I ob...   Dec 31 2011, 01:13 AM
- - Mongo   From comet-ml post #19154 by Michael Mattiazzo QU...   Dec 31 2011, 02:15 PM
- - Mongo   Comet-ml post #19169 and #19174 by David Seargent...   Jan 1 2012, 06:39 PM
- - Mongo   Comet-ml post #19176 by John Bortle: QUOTE By phy...   Jan 1 2012, 06:43 PM
- - nprev   Just heard from my stepdaughter, who returned toda...   Jan 2 2012, 03:28 AM
2 Pages V   1 2 >


Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 29th March 2024 - 07:18 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.