Astronomy news for the week starting Friday, December 17, 2010.
The Moon continues its journey, first in the waxing gibbous phase as it heads toward full on the night of Monday, December 20,
actually reaching for perfection around midnight as the date
changes to the 22nd (depending on location), when it
undergoes a grand
total eclipse that is visible throughout
all of North America.
The Moon will begin to enter the total shadow at 12:33 AM CST the morning
of the 21st. Totality respectively begins and ends at 1:41 and
2:53 AM CST, with central eclipse taking place at 2:17 AM. The
partial phase then ends at 4:01 AM. For a short time before and
after, the Moon will travel the penumbra, a region of partial
shadow (where someone on the Moon would see only a bite taken out
of the Sun by the Earth). Add an hour
for Eastern Standard Time, subtract one for MST, two for PST, three
for Alaska, four for Hawaii.
Even when in total shadow, the Moon usually remains visible with a reddish-coppery
color, compliments of light scattered into the shadow through and
by the Earth's surrounding atmosphere, the amount of light
depending on the state of the air, particularly as to how loaded it
is with obscuring volcanic debris.
On the night of Saturday the 18th, look for the rising waxing
gibbous Moon just to the right of the Pleiades cluster in Taurus, then to the left of the Hyades and Aldebaran the following evening.
After the eclipse, the Moon then gibbously
wanes, third quarter not being passed
until Tuesday the 28th.
The other major event has the Sun passing the winter solstice in Sagittarius around sunset on the evening of Tuesday the
21st, the exact time 5:38 PM CST (see above for other time zones).
At that time, the Sun will be as far south as possible, 23.4
degrees south of the celestial
equator, will be overhead at the Tropic of Capricorn, and be as
high as possible at the south pole (leaving the
north pole
in the heart of darkness). Though the days will remain cold, at
least we know that the Sun is coming back to warm the northern
hemisphere once again.
Jupiter
(dead-on the Pisces-Aquarius border) still illuminates the
evening hours as it slides to the west of the meridian within mid-twilight, while
setting around 11:30 PM, about an hour and a half before Saturn (on the
other side of the sky) rises in Virgo to the west of Spica. As the ringed planet climbs,
we await the rising of brilliant Venus, which
makes its appearance around 3:30 AM, as early as it will get for
this round. You can follow it easily into bright twilight.
Taurus does indeed take the
stage, crossing the meridian high to the south around 11 PM,
followed of course by mighty Orion, the raging Bull seeming to face the ragged
circle that makes the dim head of Cetus, the Sea Monster, which lies just north of the
celestial equator.
