Photo of the Week. An evening rose looks to the sky.
Astronomy news for the week starting Friday, October 9, 2009.
The Moon begins our week in the last stages of
its waning gibbous phase, then passes third quarter on
the morning of Sunday, October 11, when it is climbing the eastern
sky as seen from North America. We then see it slip into the waning crescent phase as it heads towards
new the night of Saturday the 17th. On Tuesday the 13th, the Moon
passes through perigee, where
it is closest to the Earth, some 5.5
percent closer than average and thus appearing 5.5 percent larger
than average, though the effect is not noticeable to the
eye.
Just after the quarter, the night of Sunday the 11th, the Moon will
pass about a degree south of bright Mars,
making for a fine sight indeed. It's a great chance to locate the
red planet. Then the morning of Friday the 16th, look for the slim crescent (your last chance to see it
before new phase) just to the southwest of Saturn and very
obvious Venus.
These two planets then put on their own small show, as Venus passes
just 0.6 degrees south of Saturn the morning of Tuesday the 13th,
the Moon seen well to the west. Since Venus is so obvious, it's a
good chance to catch Saturn, which -- though a bright first
magnitude -- will still be 100 times fainter than Venus. With both
of them now rising half an hour before morning twilight begins
(about 5:30 AM Daylight Time), the view will be within a
brightening sky, making Saturn difficult to see.
The evening provides its own show. Jupiter,
crossing the meridian to the south
about 9 PM, dominates, the giant planet not setting until 2 AM.
Since mid-June Jupiter has been in
retrograde motion, to the west against the stars of
northeastern Capricornus, caused by
the faster-moving Earth passing between it and the Sun. That
ends on Tuesday the 13th, when the king of the planetary system
stops and turns around to resume its normal easterly motion as it
heads towards residency in Aquarius
next year.
It's then not a long wait until Mars climbs above the northeastern
horizon just after midnight. The red planet is in a fine setting
to the east of classical Gemini
with Castor and Pollux pointing downward (as it
rises) more or less right at it.
Two nice asterisms are waiting for you to find. With the Moon now
out of the way, look about 20 degrees up and to the left of Jupiter
(to the northeast) to locate the Y-shaped "Water Jar" of Aquarius, then more to the east and a bit
north to catch the ragged circle that makes the "Circlet" of Pisces. Below them (to the southeast of Jupiter),
first magnitude Fomalhaut of Piscis Austrinus, the Southern Fish,
floats above the horizon.
