Astronomy, Photography and Weather

General Category => Astronomy & Space => Topic started by: martinastro on January 05, 2009, 11:44:41 pm

Title: 210P/2008 X4 (Christensen) - Catch It Quick
Post by: martinastro on January 05, 2009, 11:44:41 pm
Another comet called 210P/2008 X4 (Christensen) is also visible before dawn in the E very low in the twilight. It is located in Ophiuchus and is fading from it's peak mag of +6.0 when it was in conjunction with the Sun. It's expected to be mag +6.9 but should fade rapidly soon. It's N and E of Lulin at the moment. Could still be a bright object.


First return of a bright new periodic comet discovered by SOHO spacecraft in 2003. Now it was re-discovered by STEREO-B spacecraft. It must have been brightening very rapidly in the evening sky from September to early December. But it was not observed on the ground. Now it is too close to the sun, and not observable. But it was 6-7 mag on Dec. 24 in the SOHO images, brightening as expected (Michael Mattiazzo). It will appear in the morning sky at 8 mag in early January. Then it keeps observable in good condition while fading gradually.

From BAA...

2008 X4 (P/Christensen) should emerge from conjunction in early January, and will be visible in the morning sky at around 10th magnitude. It passed through the SOHO C3 field between December 20 and 26. Piotr Guzik however pointed out that the forward scattering geometry is very favourable and the comet could be several magnitudes brighter around December 23. Joe Marcus suggested that the forward scattering could be sufficiently strong to enhance the brightness by as much as 6.5 magnitudes, making it a prominent object in the SOHO fields. On December 21.8 it was easily visible in the C3 field at about 8.2, along with two Kreutz comets.

Title: Re: 210P/2008 X4 (Christensen) - Catch It Quick
Post by: Roman White on January 06, 2009, 11:03:37 am
Unfortunately, the conditions aren't the best and the comet got already too faint for my scope.

Alan Hale's report in
Countdown to 500 Comets: no. 446

Comet 210P/Christensen P/2008 X4

Happy New Year! I started off the International Year of Astronomy by adding
a rather unusual comet to my "Countdown" tally. This is a comet that was
originally discovered in May 2003 by Eric Christensen with the Catalina Sky
Survey, and which may be identical to an unconfirmed possible SWAN comet
that was reported the previous month. Despite its faintness at discovery I
was able to obtain a couple of visual observations of it, although I needed
the help of CCD images I'd taken to show me exactly where to look and what
to look for.

The recovery at this first predicted return was most remarkable. It was
spotted by Alan Watson of Australia in HI1b STEREO images taken December 8
as a possible new comet. After a preliminary orbital calculation by Rainer
Kracht, Maik Meyer suggested possible identity with Christensen's expected
comet, a suggestion which was quickly verified (the original prediction
being 22 days off). This turns out to be the first time a first-return
periodic comet was recovered in images taken with a spacecraft.

After putting on a good show in the LASCO coronagraphs around perihelion the
comet has now emerged into the morning sky. After an unsuccessful attempt
with a 20-cm telescope on New Year's morning, I successfully picked it up
with the 41-cm telescope the following morning. On January 2.53, m1=11.2
(extinction corrected), 1.2' coma.

The comet rapidly climbs higher into the morning sky over the coming few
weeks, but will also probably fade rapidly as it recedes from the sun and
Earth. My suspicion is that it will probably fade beyond the range of visual
detectability by about early February.

Description at

Report by J.J.Gonzalez on Jan.04
P/2008 X4 (Christensen):
2009 Jan. 4.26 UT: m1=10.1, Dia.=2.2', DC=5, 20 cm SCT (100x).
[ Mountain location, very clear sky. Beginning of astronomical twilight.
Altitude: 10 deg.].
( Pandorado, alt. 1190 m, Leуn, N. Spain )

Title: Re: 210P/2008 X4 (Christensen) - Catch It Quick
Post by: martinastro on January 06, 2009, 08:37:36 pm
Thanks for the recent visual obsv info Roman. I think I will remove that comet from my list!