The Sky This Week 12-19 Sep 2003
The Moon wanes in the morning skies this week, leaving Mars to light the night and drawing a bead on the rising Saturn in the pre-dawn sky. Last Quarter occurs on the 18th at 3:03 pm Eastern Daylight Time. Look for Luna near the Pleiades star cluster on the morning of the 16th. The next morning she stands just north of the ruddy star Aldebaran, and on the mornings of the 19th and 20th you can spot her in the company of yellowish Saturn.
As we head toward the autumnal equinox, most of you are probably noticing how the days are getting shorter. This is particularly true for early risers, who must now awake to near total darkness, when just a few weeks ago it was bright at 5:30 in the morning. This is the time of year when the rate at which the length of day changes is fastest, amounting to some two and a half minutes per day. This, coupled with the clear cool nights of autumn, make this time of the year the favorite for skywatchers.
The usually drab autumnal sky is graced by the dazzling glimmer of the planet Mars, which beams down in ruddy radiance from a perch among the faint stars of the constellation Aquarius. Mars is still quite close to earth in relative terms, and the size of his apparent disc still exceeds that of the 1988 opposition, the previous favorable one. He has started to fade slightly from his nearly -3 magnitude of late August, but he still holds the title of the brightest object in the sky after the Sun and Moon. Mars will continue to shrink in size and brightness as Earth draws away from him, but he will continue to be a fun object to study with the small telescope for several more months. His next opposition, in November of 2005, will be your next chance to see him is you miss him in the next several weeks.
The later times of sunrise play to the advantage of those of us who like to watch the morning twilight announce the dawn, but don’t like the indecent hours of summer to do so. At 6:00 you can see the golden yellow glow of Saturn high in the eastern sky, framed by the bright stars of the Great Winter Circle. Signs of the cooler weather to come abound at this hour, with the striding figure of Orion high in the southeast and the Pleiades high overhead. If you look low in the east at this hour, on a morning with a really clear sky, you should be able to spot the bright glow of Jupiter, beginning his steady plod toward the evening sky.
