SKYLIGHTS

Astronomy news for the week starting Friday, January 15, 1999.

We begin the week with the Moon very nearly out of sight. It will be visible low on the eastern horizon in dawn as an extrememly thin cresent the morning of Saturday the 16th some 27 hours before new. It then passes through new, when it is in conjunction with the Sun, the morning of Sunday the 17th, and will first be seen the evening of Monday the 18th as a very thin crescent in western twilight below Venus. The next night, look for Venus down and to the right of the crescent. The brilliant planet will make itself increasingly known as the week and the month progress as it begins to dominate the western sky. Then look for the waxing crescent to make a close pass below Jupiter the night of Thursday, the 21st, the two making a lovely pair in evening twilight. Next, look to the left of Jupiter find dimmer Saturn, which is now due south in mid-twilight. Finally, if you wait a few hours, you can see Mars, which is now rising just to the south of east a bit past midnight only a few degrees to the northeast of the bright star Spica in Virgo.

The brilliant winter stars are now at their height, the Pleiades -- the famed "Seven Sisters" cluster -- in Taurus crossing the meridian high to the south around 8 PM, great Orion just before 10. Between Orion's belt and the Pleiades lies Aldebaran, making the glowing reddish eye in the vee-shaped head of Taurus the Bull. The "vee" of stars is also a cluster, the Hyades, in mythology half- sisters to the Pleiades. At a distance of 150 light years the Hyades stars are only a third as far away as the Pleiades, so the cluster is more spread out and at first less impressive. Binoculars show a wonderful sprawl of Hyades stars that actually glow behind Aldebaran, the bright star not part of the cluster and only half the distance away. The Hyades cluster has long been a fundamental distance benchmark for astronomers, against which all other clusters and stellar distances have been compared. The Hyades is also notably older than the Pleiades and long ago lost the bright blue stars than make its younger sisters. Taurus is also a seat of active star formation. Within the confines of the constellation astronomers find great clouds of molecule-rich interstellar gas and groupings of stars that have just come into being.