Skylights featured five times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
, 5
Photo of the Week. Tree banches laden with winter's snow
glorify a deep blue sky.
Astronomy news for the two-week period starting Friday, January
6, 2006.
Welcome to the first full Skylights' fortnight in 2006, with hopes
for a good year to all. Skylights will resume its normal weekly
schedule on Friday, January 20.
The week begins on Friday, January 6, with the first
quarter Moon, which thereafter grows through its waxing
gibbous phase until it reaches full the morning of Saturday the
14th (about the time of Moonset in North America), whereupon it wanes through gibbous toward its third quarter.
The night of Saturday the 7th then finds the Moon just to the west
of Mars, while
the following night sees it to the east of the red planet. Then
the night of Friday the 13th, the Moon will be nicely ensconced
within northern Gemini with Castor and Pollux to the north of it. The
Martian placements will next be repeated with Saturn, the
Moon to the west of the ringed one the night of Saturday the 14th,
to the east of it the following evening.
Venus, which has been with us since last spring, now
takes leave of the evening sky. Very rapidly setting earlier in
bright twilight, it passes inferior conjunction with the Sun (when it is between
us and the Sun) on Friday the 13th (making no transit, as the planet passes to the north
of the solar disk), the event coinciding almost exactly with full
Moon. But no bad luck there, as the planet immediately switches
over and begins to rise in the morning sky before the Sun. By the
end of the month it will be nicely visible in growing twilight. In
the evening before inferior conjunction and in the morning shortly
after the event, Venus shows just a sliver of her daytime side, and
appears as a thin
crescent, even in binoculars. It is said that some can see the
crescent with the naked eye.
We still have two evening planets to admire. Mars, in southern Aries, now transits the meridian
high to the south around 7 PM, while Saturn, still in Cancer, rises in mid-twilight, making
its meridian transit about 1 AM, a bit over an hour before Mars
sets. But just before the red planet goes down,
Jupiter (in Libra) comes up
to dominate the heavens -- at least until Venus makes her mark in
eastern dawn.
Look of course for Orion climbing
the sky in early evening and dominating it for most of the night.
To the north of the grand figure is the pentagon that makes Auriga, the Charioteer, who holds
Capella, the sixth brightest star
in the sky and the closest of first magnitude to the north celestial pole. To the west of
Auriga and nearly overhead in early evening are the streams of
stars that make Perseus, the hero
of the Andromeda tale. The
deep south has its own charms. From the mid-southern hemisphere,
bright Achernar signals the end
of the river Eridanus, which begins at Cursa just to the west of Orion's Rigel. Between it and the southern pole lies the large triangle
made by the Alpha, Beta, and Gamma stars of "modern" Hydrus, the Water Snake, which appears
roughly to fall between our two neighboring small galaxies, and Large and
Small
Magellanic Clouds.
