Astronomy news for the week starting Friday, October 12, 2001.

Our Moon passes through its new phase this week, on Tuesday the 16th. As the crescent wanes and descends the early morning sky, it will stand directly above brilliant the morning of Sunday the 14th, and down and to the left of the planet and close to the horizon in dawn the morning of Monday the 15th. The Moon will then make its first appearance in the western evening sky as a slim waxing crescent the night of Wednesday the 17th. At the time of both crescents be sure to admire the Earthlight on the Moon, light reflected from Earth that lights up the Moon's nighttime side.

Mars continues to hang out in the post-twilight southwestern sky, as it will for the rest of the year, while Saturn and Jupiter encroach ever more into the late evening before midnight, Saturn now rising in Taurus shortly after 9 PM Daylight Time, Jupiter, smack in the middle of Gemini, about two hours later. Still-bright Mars is moving out of Sagittarius and into Capricornus, and will pass Neptune early next month. The planetary sky, however, more belongs to events you cannot see that involve the planet closest to the Sun and the one (excepting tiny Pluto) farthest from the Sun: little Mercury goes through inferior conjunction, when it is more or less between us and the Sun, on Saturday the 13th, and Neptune, in Capricornus, begins its retrograde motion on Wednesday the 17th.

The debate about Pluto's status as "planet" continues unabated. Now well north of the ecliptic path in southern Ophiuchus and nearing conjunction with the Sun, the small body -- about the size of the Western United States -- has as much in common with a slew of even smaller bodies in the "Kuiper Belt" of comets that extends from just beyond Neptune's orbit to well outside Pluto's. Pluto is the largest of them, and could be considered a transition object, so in a way it is both, a planet and a Kuiper Belt object (a "KBO" in the trade) at the same time, so everyone can feel satisfied.

Look down and to the right of Mars for a last admiration of Sagittarius and its five-star "Little Milk Dipper," which as autumn advances will slip into evening twilight. It and its summer cohort are now being replaced by the full autumn sky, the Great Square of Pegasus well up in early evening and crossing the meridian to the south around 11 PM, by which time we easily see Taurus and its two clusters: the Hyades (which make the Bull's Head) and the charming "Seven-Sisters," the Pleiades, which at first look like a fuzzy little ball until closer scrutiny resolves them into a small host of stars, the object brilliant in binoculars.
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