Astronomy news for the two weeks starting Friday, January 4,
2013.
The two-weekers must continue for a while. Thanks for your
interest and patience. The next Skylights will appear January 18,
2013.
The Moon is busy this fortnight with phases and passages. Starting
in its last quarter, the Moon spends the
first week of our period waning in its crescent phase until it reaches
new during the day on Friday, January 11. Morning people can see
the Moon to the right of the star Spica before dawn on Saturday the 5th,
while the following morning the Moon will make a flat triangle with
Spica and
Saturn (the planet to the left). Then on the mornings of
Tuesday the 8th and Wednesday the 9th, the crescent invades Scorpius, the Moon first above Antares then to the left of it.
Finally, on the morning of Thursday the 10th, those with a good
eastern horizon can see the last-glimpse crescent just to the left
of Venus. A day and a half before new Moon, our companion
passes perigee, where
it is closest to the Earth, which will bring especially high and
low tides to the
coasts.
During our second week, you might first catch the setting crescent during twilight the night of
Saturday the 12th down and to the right of Mars,
both quite difficult to see. The crescent grows until the Moon
achieves first quarter on Friday the
18th, the previous evening it being a bit shy of the phase. Nearly
invisible passages continue with the Moon going well north of
Neptune on Monday the 14th and Uranus
on Wednesday the 16th.
After terrific evening and morning appearances in 2012, Venus,
rising in mid-twilight, is fading away, its evening visit in 2013
to be nowhere near as good. But Jupiter still lights the skies,
the planet transiting high across the meridian in mid-evening just above Aldebaran and the Hyades, then dominating the western
sky until a couple hours before dawn. Saturn then does middle-duty
by rising around 2 AM in the middle of our period, the ringed
planet not transiting until near sunrise. Speaking of which, you
are about to get some relief from dark mornings. Because of the
Earth's rotational tilt and orbital eccentricity, Friday the 4th
marks the time of latest sunrise. The last of the planetary set,
Mercury, goes through superior conjunction with the Sun as our
period ends.
In late evening, look high, well above Orion (with his three-star Belt), north even of Jupiter, to find the sixth brightest star in the sky, Capella, the luminary of Auriga the Charioteer, recognizable
by his prominent pentagon of stars. The most northerly of the
first magnitude set, 46 degrees north of the celestial equator, Capella just beats out
summer's Deneb (by under one
degree) for the honor.
