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),
The red planet, now in northeastern Taurus, undergoes a passage on Wednesday the 30th, when
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.