Astronomy news for the week starting Friday, November 5, 1999.

The waning crescent Moon hovers low in the eastern dawn sky early in the week, then passes through its new phase, when it is temporarily invisible, the night of Sunday November 7. The waxing crescent then pops up in western evening twilight the night of Tuesday the 9th and grows from there toward next week's first quarter. The night of Thursday the 11th finds it just to the right of the Little Milk Dipper of Sagittarius, which is now fading into twilight. The evening crescent is also near apogee, the point where the Moon is farthest from Earth on its elliptical orbit.

The early evening is now dominated by prominent Jupiter, which is already up in the east at sunset. Even binoculars will show its four bright Moons. These four satellites, in order outward Io, Europa, Ganymede, and Callisto, are really of planetary size, Ganymede and Callisto comparable with Mercury. The innermost, Io, is the most volcanic body in the Solar System, its sulfurous volcanoes produced from heat generated by tides raised by giant Jupiter. A dozen other tiny satellites also orbit the planet.

It is Saturn that holds this week's attention, however, as the ringed planet passes opposition with the Sun on the morning of Saturday the 6th. Following Jupiter across the sky by about an hour, Saturn will then rise at sunset, set at sunrise, and cross the meridian to the south at midnight. While Saturn has even more satellites than Jupiter, it has just one big one, Titan, which is about the size of Ganymede and Callisto. It great claim to fame is that it has an atmosphere, one so thick we cannot see the surface, a surface that may contain an ocean of methane.

In the early morning, Venus grabs all the attention. Though past its maximum brightness, its fading is barely noticeable, the luminous planet still able to cast shadows and be seen in full daylight. The inner planets are nearly bereft of moons. Mercury and Venus have none at all. Ours is large, but all by itself, and Mars has but two tiny ones that are probably captured asteroids.

The "wet quarter" of the zodiac, reminiscent of an ancient rainy season, parades by in early evening, beginning with Capricornus, the "Water Goat," to the left of Sagittarius, followed by Aquarius the "Water Bearer," and then Pisces, the Fishes. Though none of these figures are very bright, Aquarius is well-represented by the tight four-star "Water Jar," and Pisces by a fairly prominent circle of stars -- the "Circlet" -- just to the east of the Water Jar.
Valid HTML 4.0!