Astronomy news for the two weeks starting Friday, December 5,
2014.
The next Skylights will appear Friday, December 19.
It's yet another two-weeker and it's jammed full of good stuff.
We begin just shy of full Moon, which is
passed the morning of Saturday, December 6, near Moonset in North
America. Look near dawn for it glowing above the northwestern
horizon. We then swing through the waning
gibbous phase, third quarter on
Saturday the 14th near sunrise, and finally through a good portion
of the waning crescent. The evening
of Friday the 5th, the Moon plows through the Hyades star cluster in Taurus, which because of the lunar
brightness will be hard to see, though you may spot Aldebaran (which is not actually
a member of the cluster). The Pleiades will be northwest of them. Then look the
night of Thursday the 11th to see the Moon passing five degrees
south of Jupiter, while the following night it will make a fine
triangle with Jupiter and Regulus in Leo. At the end we see the crescent bearing down on
Saturn the morning of
Friday the 19th. The Moon passes apogee, where it is farthest from Earth, in the
middle of our fortnight, on Friday the 12th.
Jupiter remains ascendant, rising before 10 PM as we begin our
period, shortly before 9 by the end of it. It crosses the celestial meridian to the south just
before dawn. The giant planet ceases its direct motion against
the stars of Leo to the west of Regulus on Tuesday the 9th, whence
it begins its westerly
retrograde trek.
Mars, climbing through Capricornus, continues its 8 PM setting time as it
slowly falls behind the Earth. Returning to the scene, Saturn
clears the start of twilight shortly after we began this tale
northwest of the three-star head of Scorpius. Not that anybody will notice, but Mercury passes superior
conjunction with the Sun (on the
other side of it), on Monday the 8th. You won't see it again
until 2015. Venus,
however, is slowly becoming visible within evening twilight. And
because of Earth's axial tilt and orbital eccentricity, the
earliest sunset as seen from mid-northern-latitudes arrives on
Monday the 7th. By the time of the start of winter (and shortest day) on
December 21, the evening sky is notably lighter.
One of the better and more interesting meteor showers, the Geminids, peaks the morning of Saturday
the 14th. Capable of more than a meteor a minute, the shower will
be marred by a quarter Moon. The Geminids are the debris of Comet
3200 Phaeton. Once thought to be
an asteroid, Phaeton orbits the Sun in a short period of just 1.43
years and comes well inside the orbit of the Earth (but does not
intersect us).
Right in the middle of things, in early evening find the Great Square of Pegasus high to the south, Andromeda streaming off its
upper left corner. Then around midnight climbs one of the great
glories of the sky, Orion, the
Hunter, with his silvery three-star belt and the magnificent red supergiant Betelgeuse at the upper left.
Wait a bit then to see the rising of brilliant Sirius, the brightest star of the
sky.
