Astronomy news for the week starting Friday, August 17, 2007.
The Moon begins the week in its waxing
crescent phase bound for first
quarter the night of Monday, August 20, just about the time it
is crossing the meridian to the south
in late daylight in North America, making for a near-perfect half-
Moon. Just two days before the quarter, the Moon passes apogee,
where it is five or so percent farther from Earth than average, and thus
appears about five percent smaller than average (the effect not
visible to the eye).
As the Moon then waxes in its gibbous
phase, it will make a fine sight with Antares (in Scorpius) and Jupiter the night of Tuesday the 21st as
it passes just barely south of the star with bright Jupiter
looking almost directly down upon the pair. Watch next as the Moon
transits between Scorpius and Sagittarius and then as it invades the heart of
Sagittarius's "Teapot" the night of Thursday the 23rd.
Saturn passes formal conjunction with the Sun on Tuesday the 21st,
and is thus quite invisible, along with Venus,
which passes inferior conjunction on Friday the 17th, and Mercury, which went through
solar conjunction LAST week. The remaining two ancient planets,
Jupiter and Mars,
respectively hold court in the evening and the morning. Jupiter
now crosses the meridian just before sundown and is quite obvious
in the southwest as the sky becomes dark. It makes a fine sight
and contrast with the red supergiant Antares just below it. It
sets around 12:15 Daylight Time, just a few minutes before Mars
rises in the east. In Taurus,
the red planet's placement is every bit as pretty as Jupiter's, if
not more so, as it is beautifully located between the Hyades cluster (which makes the
Bull's head) and the Pleiades.
The mythical sky is loaded with several strongmen. Winter gives us
Orion, Auriga (the Charioteer), and Perseus (not to mention the twins, Gemini), while the summer skies are
stomped by Bootes (the Herdsman
who drives the Ursa Major, the
Great Bear), Ophiuchus (wrapped
with Serpens), and the great
Hero Hercules, who presents himself
nearly overhead as the sky darkens. Look to a box of stars at the
constellation's northern end, the "Keystone," which with a star map will guide your eye to
one of the great clusters of the northern
hemisphere, Messier 13, the
"Hercules Cluster."
