Photo of the Week. Autumn leaves, blue sky, and it's
not even summer yet.
Astronomy news for the week starting Friday, April 30, 2010.
A quiet week finds the Moon mostly in its waning gibbous phase. Not until near the
end, on the night of Wednesday, May 5, does the Moon pass third quarter, which it does about the time of Moonrise
in North America. We then get to see a snippet of the waning crescent as the Moon prepares to
head toward new late next week. As it begins to climb along the
ecliptic to the north (third quarter found among the dim stars of
Capricornus), it meets up with no planets, a rather unusual
situation. Less than a day past quarter, the Moon passes apogee, where it
is farthest from Earth.
We do find planets among the evening stars, however. Venus tops our
list. As the sky darkens, find it a bit low above the west-
northwestern horizon. It's near impossible to miss. But you do
have to look early, as the brilliant planet, 10 times brighter than
the brightest star, Sirius, goes
down only half an hour past the end of evening twilight. Moving
swiftly to the east against the background stars of Taurus north the Hyades cluster (which makes the
Bull's head), Venus passes six degrees north of Aldebaran on the night of Monday
the 3rd. Note the color contrast, Venus a creamy white, Aldebaran
orange.
Moving up, find Mars. As twilight gives way to darkness, the "red
planet" (which, colored similarly to Aldebaran, is not really that
red) is now well into the southwest. Located in western Cancer between Castor-Pollux in Gemini and Regulus in
Leo, Mars is approaching the border
with Leo, which it will hit about the middle of the month. You can
continue to admire it until around 2:30 AM Daylight Time, when it
finally goes down.
Then it's Saturn's turn.
Almost exactly as Venus sets, Saturn crosses the meridian to the south in between Regulus
and Virgo's Spica. Look early enough to see this
wonderful array, from west to east, Castor and Pollux, Mars,
Regulus, Saturn, and Spica all in a ragged row, more or less like
a natural dotted line marking out the ecliptic. As Saturn sets,
around 4:30 AM, and as dawn begins to light the sky, Jupiter rises,
the giant planet now climbing into nice visibility before the sky
becomes too light.
We greet May with a prominent meteor shower, the Eta Aquarids,
which appear to come out of the constellation Aquarius. While they peak May 7-8, they are visible
during much of the month's first half. The leavings of Halley's Comet,
they normally produce some 30 meteors per hour, though the bright
Moon will severely limit the sight. Nevertheless, you might catch
a few in the early morning hours before sunrise. If you miss this
one, you can catch Halley's other shower, the Orionids, in late October.
As the Big Dipper sails high in
the mid-northern hemisphere, you might contemplate the southern
view. From the mid-southern hemisphere, the Southern Cross rides high, with Centaurus to the left, Carina to the south, all set into the glorious southern
Milky Way.
