Countdown to 500 Comets: no. 500
- Comet Lovejoy C/2011 W3
Made it to 500! My "project completed" comet is, on one hand, one of the
brightest and most scientifically interesting comets of recent years, and,
on the other hand, one of the most difficult and challenging comets I have
Comet Lovejoy is a Kreutz sungrazer, the first such comet discovered from
the ground in 41 years (although hundreds have been detected by orbiting
coronagraphs aboard spacecraft, most notably SOHO). After passing through
perihelion on December 16 it emerged into the southern hemisphere's morning
sky during the last two weeks of 2011. From all accounts, Comet Lovejoy was
a spectacular sight from the southern hemishere during that time, with a
naked-eye tail in excess of 30 degrees long, and with several observers
according it "Great Comet" status.
The situation was very different from the northern hemisphere. I did try for
the comet during daylight on several occasions as it was approaching and
receding from perihelion, but apparently it wasn't quite bright enough to
detect with the equipment I had. Afterwards, all I could do was view with
envy the images from the southern hemisphere, and read accounts of how,
after early January, it began fading, until by mid-month there was little
left but a "ghostly" tail (still quite long) and essentially no coma.
By the latter part of January the comet had traveled far enough north for me
to attempt. On the evening of the 22nd, with the 41-cm telescope I seemed to
detect an extremely pale and vague "something" with about the same surface
brightness as the gegenschein, that nevertheless moved with the expected
rate in the expected direction during the 1 1/2 hours that I followed it.
After being clouded out the next two nights I tried again on the evening of
the 25th, and once again saw this extremely pale and vague glow, and I was
able to confirm it as being the comet by following it for two hours as it
again moved with the expected rate and direction. On January 26.15, "m1" =
12.0 (extinction corrected); 3' "coma;" I would take both of these values
with the proverbial grain of salt, since I'm not sure what physical meaning
the "magnitude" has in a situation like this, and the "coma" was so
ill-defined that it was almost meaningless to attempt a size measurement; at
times it seemed to be twice this size, or even larger.
I am almost certainly finished with the comet, as the moon is now starting
to wash out the evening sky, and I'm sure there will be nothing left to
detect of it once the moon clears out. Since Comet Lovejoy may well be the
first member of a "cluster" of Kreutz sungrazers that was predicted in a
recent paper by Zdenek Sekanina and Paul Chodas, there may be more of these
comets in the years to come, and hopefully at least one will pass through
perihelion during the September/October timeframe, which will allow
observations from the northern hemisphere as well.
Description at http://www.earthriseinstitute.org/coms49.html#500
Images and reports (including reports of outreach efforts) are welcome.
- Hi everyone,
First off, I would like to thank everyone for their kind comments and words
of encouragement after I successfully added comet no. 500. (And special
thanks to Terry Lovejoy for discovering it!) It has been an interesting
ride, not only the past five years while I was actually pursuing
"Countdown," but the entire 42 years since I spotted Comet Tago-Sato-Kosaka
on that February evening way back when.
Everyone's asking, "what's next?" For one thing, I'm continuing to observe
as I always have, and I've already been looking for no. 501. (Don't have it
yet, although I've already looked for four different comets that could have
been it had I successfully detected them.) I don't foresee slowing down or
stopping anytime soon, although there will probably come a point sometime
when I no longer feel like trying to track down every single 14th-magnitude
comet that comes along. At the end of the essay I wrote when I started
"Countdown" (http://www.earthriseinstitute.org/comessay.html) I mentioned
some comets that I hope to see in the future; to those I might add comets
like PANSTARRS C/2011 L4 (it would be nice if we northerners could have a
"Great Comet" for a change), and any additional incoming members of the
Sekanina-Chodas "cluster" of Kreutz sungrazers (please, please, will at
least one of these pass perihelion during September or October so we
northerners can appreciate it, too?) While I don't expect it to get bright,
it will be most interesting to follow 67P/Churyumov-Gerasimenko during its
next return while it is being accompanied by Rosetta.
For the time being, I will continue to update my update page
(http://www.earthriseinstitute.org/comupdate.html) on an approximately
weekly basis. I will certainly include new tally additions as they are
added, although this will usually be done without announcement or fanfare.
As for future programs:
Most of you are probably aware, perhaps through my various "Countdown"
announcements, that I underwent some significant upheavals in my personal
life over the past few years, and among other things these have forced me to
put any kind of Earthrise-related activities and programs on the back
burner. However, those upheavals and changes are behind me now, and I am
once again able to focus on developing some worthwhile educational and
With that thought, yes, there will be a new comet-related observing program,
and I am currently in the process of putting it together. Although there are
still a number of details to be worked out, the primary focus will be on
scientific observations of comets, and in fact some of you have already
communicated some interesting thoughts to me along these lines, and I will
likely be incorporating these into the program. Some of you have also
privately communicated an interest in being part of such a program, and I
can pretty much guarantee I will be taking you up on that, and meanwhile
sometime in the not-too-distant future I will likely be issuing a general
call for others who might be interested, and will also likely approach a few
of you privately as well.
I also should be acquiring some new equipment within the fairly near future,
which should enable me to re-start my imaging program. I know I will never
be able to match the quality of the work of some of the talented people on
this list, but even so I would like to think I can take some images that are
somewhat aesthetically pleasing as well as scientifically useful.
So, I would just say, "watch this space!" I'm hopeful of announcing the new
program in two to three months, but we'll see. In any event, may there
continue to be comets that keep appearing for all of us to enjoy.