Astronomy news for the week starting Friday, July 6, 2001.

The Moon falls "between quarters" this week, spending the entire seven day period in its waning gibbous phase, full moon having taken place last Thursday, July 5th, the third quarter not being passed until next Friday, July 13. As it moves through the constellations of the Zodiac, it passes south of Neptune on Saturday the 7th, south of Uranus on Sunday the 8th (both planets in Capricornus), and its apogee (where it is farthest from the Earth) on Monday the 9th.

The planets put on quite a show for us this week. In the evening, Mars, four degrees south of the ecliptic and about as southerly as it can get, glows a brilliant red just to the east of the bright reddish star Antares in Scorpius. The planet, brighter than the brightest star and comparable to Jupiter, lies above the great curve of stars that make the Scorpion's tail. Since Mars moves in orbit only a bit slower than Earth, we will have it with us in the evening for the rest of the year.

The big event, however, takes place the morning of Friday, the 13th (a lucky day!) when Venus, Saturn, and the bright star Aldebaran of Taurus all gather together into a tight equilateral triangle below the Pleiades star cluster (Saturn down and to the left of Venus, Aldebaran below, to the south of Saturn). Venus is now at its earliest rising of the year, coming up just before 3 AM daylight time, about an hour ahead of twilight. As the sky grows light, you might then glimpse Jupiter and Mercury just above the east- northeast horizon, Mercury (the fainter) about two degrees down and to the right of Jupiter. The pair comes into conjunction the day before, on Thursday the 12th. Three days before, on Monday the 9th, Mercury passes its greatest western elongation, the little planet 21 degrees to the west of the Sun.

Even the asteroids get into the act, as Ceres, the largest of them (though only 900 kilometers across and invisible to the naked eye) passes opposition with the Sun on Saturday, the 7th. Only number 4 in discovery order, 500-kilometer wide Vesta (the third largest of them), can be seen without optical aid, and then just barely. Nearly 100,000 of the critters have been discovered. Vast numbers of tiny ones small enough to hold in your hand hit the Earth every day as meteorites.

Two crowns ride the nightly sky, one in the north, the other in the south. As the sky darkens, look 30 or so degrees north of the equator (nearly overhead for mid-northern latitudes) to find the gentle curve that makes Corona Borealis, the Northern Crown. If you are far enough south, around 1 AM you can watch the passage of Corona Australis, another curve of stars that makes the Southern Crown, which lies directly below the Little Milk Dipper of Sagittarius.
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