Photo of the Week. During winter's cold, enjoy a
summer sunset.
Astronomy news for the two weeks starting Friday, December 22,
2006.
Wishing you clear skies and Happy Holidays, Skylights will resume
its normal weekly schedule on January 5, 2007. Thanks and best
wishes to all.
Having just passed new, the Moon grows in its waxing crescent phase towards first
quarter, which is reached on Wednesday, December 27, after
which it waxes
in the gibbous phase to full,
which does not take place until after the turn of the year, on
Wednesday, January 3, the Moon giving us wonderful light with which
to celebrate New Year's Eve. With the Sun just past the Winter Solstice in Sagittarius, the full Moon will be
just past the Summer Solstice in Gemini and very high at midnight.
The remainder of the week sees the Moon gibbously waning.
The night of Saturday the 23rd, the Moon passes south of Neptune
(still in eastern Capricornus),
while on Christmas night it will make a very close pass to Uranus,
which currently resides in Aquarius.
You can also celebrate the New Year with Jupiter, which by January 1 will be rising just before
dawn, making a lovely sight up and to the left of Antares in Scorpius (the planet just over the border into Ophiuchus). Down and to the left
you might spot dimmer Mars, which as the year
turns rises just as dawn commences. The evening sky now holds Saturn, the
ringed planet rising in western Leo
around 8 PM on January 1. Time now too to begin looking for Venus in southwestern evening twilight. Though the
planet still sets before the sky is fully dark, its brilliance may
allow you to spot it. Get ready for a wonderful apparition of this
closest of all planets, as by late spring it will gleam gloriously
in a dark sky, not setting until near midnight Daylight Time.
Once again, however, it is
planet Earth that takes the stage, as it passes perihelion,
where it is closest to the Sun, the
same day as the full Moon, on Wednesday, January 3, thus showing
that proximity to the Sun has nothing whatever to do with the
seasons, which are caused entirely by the 23.4 degree tilt of
the Earth's axis relative to the orbital perpendicular. On that
date, the Sun will be 1.7 percent closer to the Sun than average,
a distance of 147 million kilometers, or 91.4 million miles.
Though it has passed the Winter Solstice, the Sun still rises a bit
later each morning, the result of the eccentricity of the orbit and
the axial tilt.
The bright Moon will mess up one of the grand meteor showers of the
year, the
Quadrantids (named after the defunct constellation Quadrans just to the east of the Big Dipper), which peak the
mornings of January 3 and 4 and ordinarily (in a dark sky) produce
100 or so meteors an hour.
Seasons are met with iconic constellations. None epitomizes
winter like Orion, while the
progress of autumn is told by the glorious "W" of Cassiopeia. Now with winter upon us,
the Queen begins her escape to the west. High overhead as the sky
darkens, as the evening and the season move on, she falls slowly
into northwestern skies to be replaced by Ursa Major's Big Dipper, which begins rising in the
northeast to tell of the coming of spring.
