Photo of the Week. The waning gibbous Moon rides low
in an arctic morning sky.
Astronomy news for the week starting Friday, August 3, 2007.
The waning gibbous Moon does not have far to go at
the beginning of the week before it passes third quarter on Sunday, August 5. It then
enters the waning crescent phase for the
remainder of our period, allowing the skies to darken once again,
which will bring out the stars. The morning of Monday the 6th
(night of the 5th) finds the fat crescent rather well
to the northwest of Mars, making for ready
location of the reddish planet. The following morning, that of
Tuesday the 7th, is even better, as the Moon, now to the east of
the Pleiades in Taurus, makes a fine triangle with
Mars and the cluster. Yet another morning later, that of
Wednesday the 8th, finds the Moon rising to the left of Taurus's Hyades. Lunar perigee
is passed right at the beginning of the week.
With Saturn,
Venus, and Mercury quite
out of sight near the Sun, the planetary sky
devotes itself to Jupiter and Mars. Jupiter,
now crossing the meridian just after
sunset, is into the southwestern sky by the time the sky darkens,
and sets just after local midnight (1 AM Daylight). It finally
ceases its westerly
retrograde motion against the background stars the night of
Monday the 6th. In southern Ophiuchus to the east of Antares, the planet does not quite
make it back over the border into Scorpius before it turns around and heads back to the
east.
Mars, rising just before local midnight, occupies the sky with
Jupiter for about an hour. Steadily brightening, it passes this
week into zeroth magnitude. Only nine
stars are brighter. Yet it still pales next to Jupiter, which
shines at nearly the minus third magnitude, and is nearly 15 times
brighter than Mars.
We are beginning our run up to the Perseid
meteor shower, which peaks the morning of Monday, August 13,
when you can expect to see 60 to 90 meteors an hour in a dark,
moonless sky. Even during our current week you may see a scattered
few in the early morning hours.
The Summer Triangle of Deneb (in Cygnus), Vega (Lyra), and Altair (Aquila) is now prominent in mid-evening high overhead
and stretching to the south. Look to the southern anchor Altair to
help guide you to several small constellations that include Sagitta (the Arrow) just to the
north of it, Delphinus (the Dolphin) to the
northeast, and Equuleus (the Little Horse)
to the west. Aquila is a central figure
in the summer Milky Way as
the white band plunges southward from Cygnus to Sagittarius.
