Photo of the Week. A spectacular view of the Earth's
shadow rises in the east just after sunset as seen from Mt. Wilson
Observatory, with the pink "Belt of Venus" above it, while Venus
itself is still in transit over the
Sun. Courtesy of Richard Sanderson.
Astronomy news for the week starting Friday, January 18, 2013.
The next Skylights will appear February 1, 2013. Thanks again for
your patience.
Since the end of last year, the lunar phases have been
synchronizing with Skylights' schedule, but since the quartering of
the phases averages 7.4 days long, they begin to break away. We
start with first quarter on Friday,
January 18, but then after gliding through the waxing gibbous, we do not reach full Moon until the night of Saturday the
26th with the Moon well up, Castor
and Pollux in Gemini pointing southeastward at
it. The subsequent waning gibbous fills
the rest of our fortnight, as third
quarter stretches out a bit more, the phase not passed until
Sunday, February 3.
During our first week, the Moon makes yet another great pairing
with Jupiter.
Look the evening of Sunday the 20th to see the waxing gibbous make
a nice triangle with
Jupiter and the Pleiades,
the cluster at the
top apex but hard to see in bright Moonlight. Then the following
night, Jupiter will once again (as it has for the past two cycles)
appear right up against the lunar limb with Aldebaran down below, making for
a most memorable sight (the planet actually occulted by the Moon as
seen from part of South America).
Venus, rising in bright twilight, is effectively gone, as is
its "inferior" mate, Mercury, which passes superior conjunction with the Sun
(on the other side of the Sun) as the fortnight begins. In the
evening, Mars sets
about as twilight ends and is gone as well. That leaves us with
the two dominant bodies of the planetary system, Jupiter and Saturn. Jupiter is by far the brightest starlike object in
the sky. Ending its
retrograde motion (westerly against the stars) about as our
period ends (on Wednesday the 30th), Jupiter is as far to the west
above the Hyades and Aldebaran
in Taurus as it is going to go.
Transiting high to the south across the celestial meridian in mid evening, the giant
planet (11 times the diameter of Earth) spends the remainder of the
evening in the western sky until it sets around 3 AM. Dimmer
Saturn, which spent much of last year hanging out around Spica in Virgo, now resides in Libra nearly 20 degrees to the east of the star and
rises shortly after midnight.
Among the constellations, there is
nothing quite like Orion with his bright triple-starred Belt and not one, but two, supergiants, reddish Betelgeuse up and to the left of
the Belt, blue-white Rigel down and to the right of it. The grand
classical figure is sketched out by second magnitude Bellatrix at the upper right and
Saiph at the lower left. We then
add the Sword with the Orion
Nebula below the Belt, his right and left arms, Meissa at his head, and we are
complete.
