Photo of the Week. The waxing
gibbous Moon with its heavily cratered highlands and prominent
volcanically-coated maria. Mare Imbrium is just coming into
sunlight at the upper left.
Astronomy news for the week starting Friday, December 10, 2010.
Skylights is back. As usual, we begin our week with the Moon,
which starts off in the waxing crescent
phase as it heads towards first quarter,
that phase reached during daylight on Monday, December 13th. It
thence switches over to the waxing
gibbous. The evening of the quarter, it will make a fine sight
with Jupiter,
the giant planet situated seven degrees to the south of it. So
will be Uranus, though
with the bright Moon so close, it's a telescopic object. Just five
hours before the quarter, the Moon passes apogee, where it
is farthest from Earth. The combination will make for especially
low high
tides at the coasts (as well as especially high low tides).
The two brightest planets still rule the opposite sides of the sky,
and will for some time. In the evening,
Jupiter is still nicely with us, though it makes something of
a transition as it transits the meridian to the south just as twilight
draws to a close and sets at midnight, making it a true evening
object. Picking up speed to the east, Jupiter is slowly closing in
on Uranus
, the two now within 2.5 degrees of each other. (They will
pass conjunction with each other on January 2.) In the morning, Venus
becomes ever more visible, rising now quite unmistakably around
3:30 AM, about as early as it will get.
In the gap between Jupiter-set and Venus-rise, you get to admire Saturn, which comes up about
an hour and a half after the giant planet sets. Like Jupiter,
moving easterly, it is slowly narrowing the gap between it and Virgo's Spica, the two of comparable
brightness, but not color, Spica the bluer. Back in the evening,
on Monday the 13th (a busy day), Mercury and Mars come into
conjunction (Mercury just a degree to the north), though twilight
will make the passage near-impossible to see.
The real treat of the week is the Geminid meteor shower, one of the best of the
year. The best time is the morning Tuesday the 14th, when, with
the Moon out of the way, in a dark sky you might see more than 100
an hour emerging from the direction of the constellation Gemini. They are the leavings of
"asteroid" 3200 Phaeton, which is now suspected of being a
dead comet with a period of just 1.4 years.
As the winter stars approach, Orion rising as Jupiter sets, we can begin saying
goodbye to fall's Fomalhaut
(the luminary of otherwise dim Piscis
Austrinus, the Southern Fish), which lies well to the south of
Jupiter. To the left of (and almost joining with) it lies the
modern constellation of Sculptor,
the Sculptor's Studio.
