SKYLIGHTS

Astronomy news for the week starting Friday, June 11, 1999.

The Moon wanes through its final crescent at the beginning of the week, and passes through new on Sunday the 13th about noon for most of the US. It passes perigee, its point closest to the Earth, only 20 hours earlier. The morning of Saturday, the 12th, the very slim crescent will lie in eastern twilight below Saturn (now visible in early morning) and brighter Jupiter. By the night of Monday, the 14th, the Moon's waxing crescent will be just visible in western evening twilight, but will put on a better show the following two nights. On the night of Tuesday the 15th, it will be to the left of Mercury, which is beginning to make an appearance, and better, the night of Wednesday the 16th, it will appear just below brilliant Venus, the sight well worth a look and maybe a photo.

Venus, well to the northwest in evening, makes a show for itself as well. It is passing to the east through central Cancer between Gemini and Leo, and in the middle of the week will be just to the east of the Praesepe (Beehive) star cluster. In a dark sky, the Beehive, 500 light years away, is visible to the naked eye as a faint smudge, and is easily seen in binoculars. At the beginning of the week, on Friday the 11th, Venus also passes its greatest elongation 45 degrees to the east of the Sun, and will set about as late as possible.

Venus's rival Mars then takes center stage. Though having begun its direct motion in Virgo near Spica, the movement is still quite slow, reddish Mars and bluish Spica making a fine pair for some time yet to come, the two looking down as if a pair of celestial eyes. The planet made wonderful news last week with its first accurate topographic map, produced by the Mars Global Surveyor. The huge Hellas basin, one of the largest impact features in the Solar System, drops 6 miles deep, while Olympus Mons, the largest volcano, rises 17 miles into the thin carbon dioxide air.

As summer approaches, the classic summer constellations begin to make convenient appearance. Scorpius, with bright Antares, is due south at local midnight, while Sagittarius, easily recognizable by the five-star "Little Milk Dipper," crosses the meridian an hour later, the brightest part of the Milky Way now cascading through them. Just above Scorpius is sprawling Ophiuchus, which represents Ascelpius, the ancient healer.