Astronomy news for the week starting Friday, August 11, 2000.

The Moon waxes through its gibbous phase early in the week, reaching its full phase on the night of Monday, the 14th, when it will rise around sunset, set near sunrise, and be up all night. With the Sun now just having passed into Leo, this month's full Moon will be near the Capricornus-Aquarius border. Since Neptune and Uranus both recently passed opposition with the Sun, the Moon encounters them both before it reaches full, Neptune on Sunday the 13th, Uranus a day later.

Venus still lies very low and almost out of sight in the northwestern evening twilight sky, but will gradually make an appearance as the month wears on. At the same time, Jupiter and Saturn make an official appearance in the evening sky, both now rising just before local midnight (1 AM daylight time). Jupiter, in Taurus and just to the east of Saturn, is unmistakably bright, second in the sky only to Venus (not counting Mars, which at its very closest can for a time become brighter than Jupiter). Jupiter is still slowly pulling away from Saturn, and will keep doing so until fall and the two enter their retrograde motion (caused by the Earth swinging between them and the Sun). The two Solar System giants make a fine sight situated roughly between Taurus's two clusters, the Hyades (which make Taurus's head) and the Pleiades (the famed Seven Sisters).

Though the bright Moon blots out the fainter stars, it cannot defeat the Summer Triangle of first magnitude stars, which consists of Vega in Lyra (at the western apex), Deneb in Cygnus (at the eastern), and Altair in Aquila (southern). All are white "class A" stars, but the similarity ends there. Vega is the hottest and apparently brightest of the trio, rapidly-rotating Altair the closest and coolest, and Deneb by far the most distant and luminous. Deneb, a rare white supergiant star, if placed at Vega's distance, would be many times brighter than Venus and would cast easily visible shadows on the ground.

Such large configurations that join constellations are not common in our constellation lore. The best-known are the Summer Triangle and the Winter Triangle that joins Orion, Canis Major, and Canis Minor through Betelgeuse, Sirius, and Procyon. Lesser known is the Great Diamond that links Leo, Virgo, Bootes, and the modern constellation Canes Venatici through Denebola, Spica, Arcturus and Cor Caroli. In the Southern Hemisphere, the False Cross joins Vela with Carina, making a lesser version of Crux, the famed Southern Cross.
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