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Comet Holmes

Photo of the Week. By November 11 of last year (as seen here), Comet Holmes had widened and had closed in on Mirfak (Alpha Persei) in Perseus. By November 23rd, it had passed to the other side of the star. (See it on October 31.)

Astronomy news for the week starting Friday, January 25, 2008.

In its waning gibbous phase at the start of the week, the Moon heads towards third quarter on Tuesday, January 29th, the phase hit around the time of Moonrise in North America. The last few days of the week are then spent within the thinning waning crescent. We end the month of January with the Moon at apogee, where it is farthest from the Earth.

The morning of Friday, February 1, is special, and well worth a look even in the bitter cold of winter. For many weeks now, Venus has been slowly sinking toward the eastern horizon as seen around dawn (the planet now rising around 5:15 AM, just before the commencement of twilight). At the same time, having passed conjunction with the Sun last December, Jupiter has been moving up from the horizon. The morning of Friday the 1st, these two brightest of planets will pass in glorious conjunction a mere 0.6 degrees apart, just a bit more than the angular size of the full Moon, Venus (six times brighter than Jupiter) to the north. Look to the southeast from a location with a decent horizon around 6 AM or a little before. At the same time, the morning sky will be enhanced with the crescent Moon, which will lie just to the west of Antares in Scorpius, all making for a grand view. As February then progresses, the two planets will separate, Jupiter moving up at dawn, Venus sinking toward twilight, though it will remain with us through the month of February.

That leaves us with Mercury (lost in evening western twilight, but glorious as seen by the recent Mercury Messenger flyby), Mars, and Saturn. The red planet, now in northeastern Taurus, undergoes a passage on Wednesday the 30th, when it ceases retrograde motion and begins moving again to the east against the stars, heading again toward Gemini. The planet's orbital inclination has raised it a full three degrees north of the ecliptic, making it pass especially high for mid-northerners at its 9 PM transit of the meridian. Descending the northwestern sky, Mars does not set until around 5 AM, less than an hour before Jupiter and Venus rise. Again, in between is Saturn in Leo to the east of Regulus, which comes up over the eastern horizon at 7:30 PM just as twilight ends, and crosses to the south around 2 AM.

As twilight ends, look for Perseus nearly overhead. As the King and Queen (Cepheus and Cassiopeia, who in myth become the Hero's in-laws) drift now into the northwest, they are replaced by the northeasterly rising of Ursa Major and its Big Dipper, whose front two bowl stars point to the left toward Polaris, which anchors the end of the much fainter Little Dipper.
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