Astronomy news for the week starting Friday, March 13, 2009.
The week begins with the
Moon in its waning gibbous phase,
which ends with the third quarter on
Wednesday, March 18, about the time of Moonset in North America.
We then get to see a bit of the waning
crescent before Friday rolls around again. That the week has
seven days is no surprise, as the weeks mark off the intervals
between the lunar phases of the moment (new, full, the quarters).
With the Sun nearly at the
Vernal Equinox in Pisces, this third quarter will be
the lowest of the year, falling just shy of the Winter Solstice, between the classical
figures of Sagittarius and Scorpius.
The morning of Monday the 16th, the Moon will seen to the west of
Scorpius's Antares (the two
always making a fine sight), while the following morning they will
be much closer, with the Moon now to the east of the star. The day
after last quarter, on Thursday the 19th, the Moon then passes apogee, when it
will be farthest from Earth.
Plunging toward the Sun, Venus is notably
lower in the western sky, setting before 9 PM, and by
8:30 in twilight at the end of the week. The evening now
more and more belongs to Saturn, which is
already up in the east at sunset and crosses the meridian to the south just before
midnight. The star close to it is fourth magnitude Sigma Leonis.
In the morning sky, Jupiter glows in
twilight close to the southeastern horizon.
Creeping slowly along the ecliptic at a degree per day,
the Sun finally reaches the Vernal Equinox on the celestial equator
the morning of Friday, March 20, about the time of sunrise in North
America, allowing for a bit of morning celebration.
Spring in the northern hemisphere formally begins at 6:44 AM
Central Daylight Time (7:44 EDT, 4:44 PDT). On that day, the Sun
will rise due east, set due west (rendering days and nights
more or less equal), and be overhead at the Earth's
equator. It also formally rises at the north pole
and sets at the
south pole, though refraction by the Earth's atmosphere and the
finite diameter of the Sun advances the "rise" and delays the "set"
by a bit.
Comet Lulin
is both fading away and moving more slowly. This week it spends
its time in central Gemini,
passing just south of Delta
Geminorum the middle of the week.
