The Great Christmas Comet of 2011, 2011 W3 (Lovejoy) Options

[Mongo]

From comet-ml post #18977:

Hi All,

I have to eat my words to friends about this comet. Looks just like Ikeya-Seki in 1965. A really beautiful Xmas present.

I got a series of images this morning but have no website, so one of the better ones appears in the nzastronomers site.

I estimated the visible tail length at 18 degrees, and the head was still out of sight below the local horizon here in New Plymouth, New Zealand.

[Mongo]

From this Brazilian Portuguese-language blog:

[Mongo]

From comet-ml post #18990 by Robert McNaught:

After several nights or mornings of poor weather, and the prospect of these continuing here at Siding Spring, I decided it was time to move. This morning gave an opportunity to find clear sky about 20km to the west, away from the mountain fog and orographic cloud. And boy, was it worth it! This is a most beautiful comet.

The tail was very obvious to the naked eye, rather brighter than the Milky Way in Circinus, Norma and Ara but not quite as bright as in Crux and Carina. The split between the dust and gas tails was clearly evident to the naked eye.

10x50 binoculars didn't show much more tail length, but structure was present, especially the "spine" along the southern edge of the dust tail, continuing past the bifurcation of the dust and gas tails. The end of the dust tail fades off very rapidly and naked eye, 10x50B and various photos have the tail reaching RA 15h54m Dec -40.0 (2000) The ephemeris position at that time was RA 17h02.3 Dec -34d56' (2000) giving a dust tail of 14.3 deg. The gas tail is perhaps 1 deg longer but fades away much more gradually and thus has a less well defined end point. The edges of the dust and gas tail are very sharply defined.

The tail brightness from the bifurcation towards the head was quite uniform, but as twilight progressed, the tail near the head became lost in the twilight and I didn't see the head visually or record it on photos. This is not a strong conclusion, as I had to move to a better location to find a lower horizon and the sky brightness probably beat me. I'd be reasonably confident that from tomorrow onwards I'll be able to make some meaningful statement about the visibility of the head.

To place this comet in the pantheon of modern comets (essentially subjective), I'd put it in the class of Hale-Bopp, Hyakutake and Bennett with this morning's view.

I'll try to get some photos up later today.

Cheers, Rob

[Mongo]

Here is a photo from this morning by outbackmanyep from Bendemeer, New South Wales, Australia:

[Mongo]

Photo from this site:

[ugordan]

Wow.

[scalbers]

Very nice. Looks rather brighter than pieces of Milky Way in the image. With the help of Mongo's finder chart one can see Antares in the lower left corner, and Mu Scorpii to the upper right of the comet head.

On the spaceweather.com site there is a timelapse of the comet rising as seen from western Australia by Colin Legg. Worth looking at full screen:

http://vimeo.com/34007626

[Mongo]

There are some incredible movies now available from the Sungrazer website, which is linked to in the very first post in this thread.

First is this 7MB Quicktime movie from STEREO/SECCHI COR-1B. Very spectacular -- you first see the comet approaching the sun from the lower right, then the headless tail receding to the upper left, then the tail-less comet nucleus moving away from the sun toward the lower right as it begins to generate a new tail.

Second is this 30MB WMV movie from STEREO/SECCHI HI-1A, also a very striking movie of the comet departing from the sun..

[Mongo]

The latest image of Comet Lovejoy, by Colin Legg. The comet is starting to move into darker skies.



Here is the latest report from Dave Herald from comet-ml post #19013:

At long last the skies are clear in the Canberra region. The nucleus for Lovejoy doesn't rise for another half hour. But already the tail is visible to the naked eye, extending a full 10 deg above the horizon. The surface brightness is similar to the Magellanic clouds - even though they are higher in the sky.

Dave Herald
Murrumbateman, Australia

[Stu]

Good grief... view from the ISS...

http://www.flickr.com/photos/nasa2explore/6555113049

[Tesheiner]

Wow!

[Stu]

Lovejoy Rising...

[centsworth_II]

This time lapse via a tip from Emily's Twitter:
http://www.nasa.gov/multimedia/videogaller...ia_id=125774121

[Stu]

Just saw that, wish I'd noticed there were earlier images to begin the sequence sooner. Oh well...

[Mongo]

From comet-ml post #19028 by Dave Herald:

A bit more on the brightness...

The comet’s tail for the first 12+ degrees is definitely considerably brighter in surface brightness than the adjacent Milky Way band at similar altitudes. My comparison with the Magellanic clouds was of the tail at around 10 deg altitude, with the Magellanic clouds at 40 to 50 deg altitudes, with significant atmospheric absorption at low altitudes.

Re tail length. With the nucleus at 17h 00.6m –37d 10’ (but no condensation visible at that location), the dust tail extended to around 15h 44m, –43.0d, and the ion tail extended to about 15h 58m, –44.3d – giving tail lengths of around 16 deg.

Rob refers to P/ Halley 1986. IMHO, Lovejoy is MUCH more spectacular and visible than Halley was at its best. However it is considerably less spectacular than McNaught was at its best. Overall – it is in the category of ‘spectacular’ comets. Commiserations to those in the northern hemisphere, who won’t be able to see this marvellous Xmas comet.

Dave Herald
Murrumbateman, Australia


From: Robert McNaught
Sent: Friday, December 23, 2011 5:56 AM
To: Comets-ml
Subject: Re: [comets-ml] Comet Lovejoy Spotted From Space Station

Confirming Dave Herald's comment on the brightness of the tail, I made it brighter than the surface brightness of the Small Magellanic Cloud (SMC) on Dec 21.7 UT, but comparable to the LMC. A more subjective comparison (again) would make it much more impressive than P/Halley in 1986 which I saw pretty much every night for over a month after perihelion.

Cheers, Rob