SKYLIGHTS
Astronomy news for the week starting Friday, December 10, 1999.
The Moon waxes through its crescent phase this week, reaching first
quarter the night of Wednesday the 15th shortly before moonrise in
North America. On its way to the quarter it will embrace a host of
planets, occulting (or passing over) Neptune on Saturday the 11th
and then both Mars and Uranus on Sunday the 12th. Unfortunately
the events take place in the daytime. Nevertheless, Mars and the
Moon will still put on a nice show in the southwest early on the
evening of Sunday the 12th. Since the occultation takes place
about 1 PM Central Time, by nightfall the Moon will have moved only
a bit to the east, and as a result will make a close couple with
the red planet right in the middle of the constellation
Capricornus. Go look!
The Moon passes Mars only two hours before passing Uranus, so Mars
begins the week just to the west of the much more distant giant
planet. Since Mars is closer to the Sun, however, it is moving
much faster to the east against the stellar background, and on the
night of Monday the 13th will pass only 0.7 degrees to the south of
Uranus. The conjunction will provide a fine chance to locate the
dimmer planet, which is itself passing an excellent guide, the much
brighter fourth magnitude star Theta Capricorni. Look just above
Mars to find the star, and then just barely below the star to find
Uranus. Though Uranus is at the edge of naked-eye vision,
binoculars will be needed.
Our sky is also graced this week by one of the best meteor showers
of the year, one that is -- unlike the Leonids of last month --
quite reliable. The Geminids, which appear to radiate from the
constellation Gemini, will come to a maximum the night of Monday
the 13th. With the Moon out of the way and Gemini climbing the
sky, you may see up to two meteors per minute after midnight. The
Geminids are the fluffy debris that has been flaked from 3200
Phaeton. Once thought to be an asteroid (and carrying an
asteroid's name), Phaeton's connection with the meteor shower
clearly indicates it to be a "dead" comet, one whose orbit we pass
every December.
While admiring Mars and meteors, be sure also to pay heed to the
giants of the Solar System, to Jupiter and Saturn, which are high
in the sky just to the south of the flat triangle that makes the
classic figure of the constellation Aries. Below them lies Cetus,
the Sea Monster of the Perseus myth, its lonely bright star Deneb
Kaitos in the monster's tail shining below the Great Square of
Pegasus.
