Astronomy news for the two weeks starting Friday, December 16,
2011.
Skylights will next appear December 30, 2011.
And a happy holiday season to all. Our fortnight pretty much spans
the lunar crescents, starting with the last
quarter on Saturday, December 17. It then runs through the
eastern morning waning crescent to new
on Christmas Eve around noon in North America, then switches to the
western skies as the evening waxing
crescent, which will grow until first
quarter on New Year's Eve. The night of Wednesday the 21st,
the Moon will pass perigee, where
it is closest to the Earth.
The night of Friday the 16th sees the Moon several degrees to the
southwest of Mars.
Then the morning of Monday the 19th, the Moon will rendezvous with
Saturn and its
current partner Spica, to the west
of the ringed planet, while the following morning it will below the
pair. As the Moon then thins, on the morning of Thursday the 22nd,
it will appear to the right and a bit up from
Mercury, which will be making a nice appearance in dawn's
light. After the new phase, next look for the Moon to the right of
very obvious Venus the evening of Monday the 26th, then above it
the following evening. In far lesser events, the crescent will
pass north of Neptune on
Wednesday the 28th, while (to complete the year) similarly taking
on Uranus on
Saturday the 31st.
Planets are all over the sky. Venus hath
arrived, for sure. Look into the southwest in late twilight to see
it glowing brightly above the horizon, not setting until half an
hour or more after the sky gets fully dark. Next up is
Jupiter, which crosses the meridian by 8 PM and does
not set until shortly after 2 AM. Still south of classical Aries, Jupiter ceases
retrograde motion on Monday the 26th, thereafter resuming its
normal easterly trek against the stars. More than an hour before
midnight, Mars then rises to the south of Leo's hindquarters, the red planet crossing the
meridian just before morning twilight begins. That leaves Saturn
and Mercury. The ringed planet, beautifully positioned in Virgo to the northeast of Spica,
rises just a hair before Jupiter sets. Our smallest planet
actually rises in the morning dark just before dawn, and on
Thursday the 22nd, passes seven degrees north of Antares, goes through greatest
western elongation relative to the Sun, and, as
noted above, appears a bit down and to the left of the waning
crescent Moon. In a lesser event, Pluto goes through conjunction
with the Sun on Thursday the 29th.
Our own Earth makes bigger
news, as the Sun passes the Winter
Solstice in Sagittarius at
11:30 PM CST on Wednesday the 21st (10:30 MST, 9:30 PST, 12:30 AM
EST on the 22nd) to mark the beginning of astronomical winter. On
that date, with the Sun as far south as it gets (overhead at the Tropic of Capricorn), we in the
northern hemisphere will have our shortest day and longest night of
the year.
Though winter is upon us, the northern sky still presents a set of
autumn constellations. In early
evening, look for the "W" of Cassiopeia a bit to the west of overhead. Farther west
is the dim pentagon-shaped figure of her husband, Kingly Cepheus, while to the east lie the
star-streams of the hero Perseus,
the rescuer of Andromeda, who
lies south of the Queen.
