[新闻] This Is SKY & TELESCOPE’s AstroAlert for Comets

NEW COMET IN HERCULES

Using giant 20 x 120 binoculars, Japanese amateur Tetuo Kudo
has discovered a comet of 9th (or perhaps) 8th magnitude,
moving east-southeast through Hercules. He made the find
early on the morning of December 14th (local time).
According to the announcement on IAU Circular 8032,
confirming CCD images by Ken-ichi Kadota (Saitama, Japan)
revealed a short tail about 1/3 degree in length, pointing
away from the Sun.

A preliminary orbit calculated by Brian G. Marsden of the
Minor Planet Center in Cambridge, Massachusetts, indicates
that this comet is headed for perihelion in late January,
when it will pass well inside the orbit of Mercury and may
brighten considerably. Unfortunately, it will then be
almost directly *behind* the Sun as seen from Earth, hence
virtually impossible to observe. Before that time, Northern
Hemisphere observers should be able to follow the comet
with binoculars in the morning sky through mid-January.
Skywatchers in the Southern Hemisphere are in a position
to see it emerging from the Sun's glare in late February,
in the evening sky.

Congratulations, Tetuo Kudo!

The ephemeris below, calculated from Marsden's preliminary
orbital elements on Minor Planet Electronic Circular
2002-X84, gives the comet's right ascension and declination
(equinox 2000.0) at 0 hours Universal Time on selected
dates. Also listed are the comet's distance from the Earth
(delta) and Sun (r) in astronomical units (where 1 a.u. is
about 149,600,000 kilometers), its elongation angle from
the Sun in degrees, predicted magnitude, and the
constellation though which it is passing. (If the numbers
in the columns don't line up properly, reset your e-mail
program to a fixed-width type font like Courier.)

Visit http://cfa-www.harvard.edu/iau/cbat.html for
information on subscribing to the IAU Circulars. Or go to
http://cfa-www.harvard.edu/iau/mpc.html for similar
information relating to the Minor Planet Center's
many services.



Roger W. Sinnott

Senior Editor
Sky & Telescope


-----------------------------------------------------------
                                                         
                Comet C/2002 X5                          
                                                         
Date     R.A.      Dec.   Delta    r    Elong. Mag. Const.
(0h UT)   h   m     o  '    a.u.   a.u.     o              
                                                         
Dec 15   15 54.3  +44 48   1.085  1.210   71.4   7.5  Her
Dec 16   16 02.6  +44 13   1.069  1.189   70.6   7.4  Her
Dec 17   16 11.0  +43 35   1.054  1.167   69.8   7.3  Her
Dec 18   16 19.5  +42 54   1.039  1.146   68.9   7.2  Her
Dec 19   16 27.9  +42 09   1.025  1.124   68.0   7.1  Her
Dec 20   16 36.4  +41 22   1.012  1.102   67.0   6.9  Her
Dec 21   16 44.9  +40 31   0.999  1.080   66.0   6.8  Her
Dec 22   16 53.4  +39 36   0.987  1.058   64.9   6.7  Her
Dec 23   17 01.8  +38 38   0.976  1.035   63.8   6.6  Her
Dec 24   17 10.2  +37 37   0.966  1.012   62.6   6.5  Her
Dec 25   17 18.5  +36 32   0.957  0.989   61.3   6.4  Her
Dec 26   17 26.7  +35 24   0.948  0.966   60.0   6.2  Her
Dec 27   17 34.9  +34 13   0.941  0.943   58.6   6.1  Her
Dec 28   17 42.9  +32 59   0.934  0.919   57.2   6.0  Her
Dec 29   17 50.8  +31 41   0.928  0.895   55.7   5.9  Her
Dec 30   17 58.6  +30 20   0.923  0.871   54.2   5.7  Her
Dec 31   18 06.2  +28 57   0.919  0.846   52.7   5.6  Her

这个彗星叫C/2002 X5 (Kudo)，在网上搜索发现周兴明发现的一颗SOHO彗星也叫C/2002 X5 (SOHO)：
http://www.rzuser.uni-heidelberg.de/~shoenig/sohocoms.html
为什么会有重名？