SKYLIGHTS

Astronomy news for the week starting Friday, August 25, 2000.

We begin the week with the Moon just short of perigee, when it is closest to the Earth, as it heads toward its new phase on Tuesday, the 29th (which it reaches just about sunrise in North America). It will then become visible as a thin crescent in western evening twilight the night of Wednesday, the 30th -- providing you have a good, flat horizon.

Planets now begin to invade the evening sky, though just barely. First in line after sunset is brilliant Venus, which though climbing a bit every night, is still visible only in western twilight. Let the Moon be your guide. The night of first lunar visibility, Wednesday the 30th, Venus will shine just down and to the left of the lunar disk, the two making a wonderful evening sight that should not be missed, though you will have to look early, shortly after sunset.

In the other direction, to the east, Jupiter and Saturn are now rising before midnight, Saturn around 11:30, Jupiter about twenty minutes later. Set within the beautiful stars of Taurus, they bring a reminder that northern autumn is on its way, the sky's great Bull presiding over chilling weather as the Sun descends through Leo toward the autumnal equinox, which it will reach in less than a month, on Friday, September 22.

To complete the roundup, Uranus and Neptune still hang around in the evening amidst the stars of Capricornus, while Mercury lies too close to the Sun to be seen (having just cleared its superior conjunction with the Sun last week). Finally (ignoring dim Pluto), Mars is now clearing the morning Sun, and is just barely visible low on the eastern horizon in dawn's light.

With the Moon out of the way, this is a fine time of year to admire the Little Dipper, the chief figure of Ursa Minor, the Smaller Bear, which in early evening now stands almost straight up on its handle. Perpetually rounding the north celestial pole, and always visible for those living above 20 degrees north latitude, the Little Dipper's chief star, Polaris, closely marks the pole itself. While the Dipper's two front bowl stars, Kochab and Pherkad, are relatively bright, the rest of its stars are quite faint and hard to find unless the sky is fairly dark. Down and to the left see Ursa Major's Big Dipper, and down and to the right Cassiopeia, which, with Taurus, is another harbinger of the autumn soon to come, the three constellations acting for us as a giant calendar.