Astronomy news for the week starting Friday, September 25, 2009.
We begin the week, the night of Friday, September 25, with the Moon right at its first quarter, and at about midnight too in
North America, allowing you to see the near-perfect quarter on the
meridian to the south in its full
glory. With the Sun just past the Autumnal Equinox in Virgo, the quarter, 90 degrees to the east of the Sun, will shine low to
the south among the stars of Sagittarius just to the east of the Winter Solstice. The Moon then spends
the rest of the week in its waxing gibbous
phase as it heads towards full the night of Saturday, October 3.
Watch then as the Moon takes on Jupiter. It
will appear to the west of the giant planet the night of Monday the
28th, then will make a fine appearance just to the northeast of it
the following evening. Half a day later, the Moon invisibly passes
Neptune, which lies just to the east of the King of the
planetary system. The night of Sunday the 27th, the Moon passes apogee, where it
is farthest from the Earth in its somewhat
elliptical
orbit.
For some time now, Jupiter has been eminently visible as an evening
planet. As September passes into October, it crosses the meridian
to the south around 9:30 PM Daylight Time, then sets around 2:30
AM. In between, half an hour after midnight (Daylight Time), Mars
rises, beautifully placed just to the south of Castor and Pollux in Gemini. Note its color relative to white Castor and
orangish Pollux. Rising ever later, Venus does not loft
herself up above the eastern horizon until about 5 AM. But the
advent of twilight is getting later too, so the brilliant planet
still rises in a dark sky, beating dawn by half an hour. Moving
rapidly to the east against the stars, Venus passes through
southern Leo to the southeast of Regulus.
Then its Mercury's turn, the
little planet rising just as twilight barely begins to light the
sky, as it heads toward greatest western elongation next week. At
about the same time, Saturn, which
has cleared the Sun and is somewhat fainter than Mercury, makes its
morning debut. The two will come into conjunction with each other
late next week just 0.3 degrees apart.
The "wet quarter" is upon us, this area of the sky featuring the
three watery constellations of the
Zodiac. First up is Capricornus, easily found using bright
Jupiter, which hovers to the west of the Water Goat's northeast corner made of
Delta and Gamma Capricorni. (But wait until
the Moon is out of the way.) The rest of it appears like an old-
fashioned upside down hat to the west and south. To the northeast
of Capricornus look for the "Y" of stars that makes Aquarius's Water Jar and a bit more to the west to locate the Circlet of Pisces, the Fishes. Well south of the Water Jar lies
the bright star Fomalhaut, of
Pisces Austrinus, the Southern
Fish.
