Astronomy news for the two-week period starting Friday, January
Welcome to the New Year. May 2009 be good to you.
Starting the week as a fat waxing crescent
just shy of first quarter, which is
passed on Sunday, January 4, the Moon spends the rest
of the first week of our fortnight growing in the waxing gibbous phase. Full Moon is then reached on Sunday the 10th,
after which our companion will enter the waning gibbous as it heads toward third quarter the night of Saturday the 17th.
Perigee, where the Moon is closest to Earth, falls on the same
day as the full Moon, resulting in especially high tides at the coasts.
Though the Moon will pass north of Uranus on Friday the 2nd, the only real
encounter of note is with Leo and
Saturn. Take a
look the night of Monday the 12th, around 11 PM, when the Moon will
lie just to the west of Regulus.
By the next evening, the Moon will have flipped to the other side
of the star, falling between it and Saturn, while the night of
Wednesday the 14th, the Moon will be seen a few degrees to the
south of the ringed planet, the Moon, Saturn, and Denebola (at Leo's tail) all in a
row toward the north.
During our two-week interval, both the inner planets reach their
greatest eastern elongations relative to the Sun. Mercury gets
there first, on Sunday the 4th, when it will be seen near Jupiter (the
giant planet becoming lost to twilight). Venus then repeats
the act on Wednesday the 14th. Look the night of Friday the 9th to
see Jupiter, Mercury, and Venus all in a row upward from the
horizon. Shining gloriously in the southwest, Venus does not now
set until around 9 PM. Though the Sun will henceforth begin to
catch up with it, since the Sun is now setting later, so will Venus
until early in February.
The Earth made
the show last December when it passed the Winter Solstice, and now does it again by passing
perihelion on Sunday the 4th (a popular date), where it will be
closest to the Sun, 91,400,000 miles (147,096,000 kilometers) away,
1.107 percent closer than average. Given the northern weather,
solar distance obviously has little to do with the seasons, which
are caused by the tilt of the Earth's axis. Our proximity to the
Sun will enhance the tides still further.
Early January is home to one of the finer meteor showers of the
Quadrantids, which emanate from
the defunct constellation Quadrans
(the Quadrant), which once marked stars to the east of the Big Dipper's handle. Capable of
producing close to two meteors a minute, the shower will be best
viewed the morning of Saturday the 3rd, and the farther west the
observing site the better.
Switching from the northern sky to the southern, Sirius, the bright Dog Star, crosses
to the south around midnight, bringing along with it the vastness
of Argo, the Ship of the Argonauts.
For northerners, the most accessible of the three parts into which
the Ship is now divided, Puppis
(the Stern), wraps itself to the east and south of Sirius's
constellation, Canis Major.