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Photo of the Week.. Winter is here...
Astronomy news for the week starting Friday, December 24, 2004.
Best wishes for a fine holiday season to all.
The last full week of the year begins with a bright Moon in its waxing
gibbous phase just short of full, that
phase reached on the morning of Sunday, December 26, shortly
after sunrise and moonset for continental North America. As a
result, the near full Moon will rise just before sundown Christmas
night, and will rise just after sundown the following evening. A
day later, on Monday the 27th, the Moon will go through
apogee, where it is farthest from the Earth. The remainder of
the week the Moon wanes in
its gibbous phase toward the third quarter, which will be passed on
January 3. Around midnight the night of Monday the 27th, the
apogean Moon will pass five degrees to the north of Saturn,
between the planet and Gemini's
The year ends with sense of grand symmetry. Saturn, which we have
watched moving ever more into evening skies, now rises during
twilight, while Venus --
which we have seen lowering in morning skies, rises just as
twilight begins. In between, Jupiter
rises shortly after midnight. During the early part of the week,
the bright planets remain strung out in order from the Sun, starting with Mercury,
which is low in southeastern morning twilight, then passing through
Venus, then to Mars in Libra. Continue on to Jupiter,
which, as the sky brightens, is high toward the south in Virgo and to the west of the star Spica, then on to Saturn in Gemini.
The progression ends the night of Tuesday the 28th, when Mercury
and Venus swap places. Mercury, climbing upward in dawn to reach
greatest western elongation on Wednesday the 29th, passes
conjunction with Venus on the 28th, when the two are just over a
degree apart, Venus to the south of fainter Mercury. Watch as the
two inner planets play tag with each other. They will reverse
their positions again on January 13 of next year, when the outward
planetary progression resumes.
Four classic northern constellations surround Polaris and the North Celestial Pole. To the east, above
mighty Orion, is Auriga with bright Capella. Moving then to the west,
we find three major constellations of the Perseus myth: Perseus himself (the Hero of the
story), Cassiopeia (the Queen), and
then rather far over, her husband, Cepheus (the King), which is practically invisible when
the sky is flooded with bright moonlight. To the south of
Cassiopeia lies her daughter Andromeda, while between Auriga-Perseus and the pole is
the faint modern figure of Camelopardalis, the Giraffe.