Astronomy news for the week starting Friday, July 22, 2011.
Skylights now resumes its normal weekly schedule.
And we begin it with a third quarter Moon,
which appears the night of Friday, July 22, around moonrise in
North America, allowing for a near-perfect split of the Moon into
its daytime and nighttime halves. It thereafter progressively
slims in its waning crescent
phase until it finally disappears from view as a new Moon on
Saturday the 30th. Your last view of an ultrathin crescent might
(with a clear eastern horizon) be had as our week ends, on the
morning of Friday the 29th.
As our Moon glides along its path, it encounters pairs of planets
and clusters. The morning after the quarter, that of Saturday the
23rd, finds our companion up and to the west of rising
Jupiter, while the next morning, the crescent will appear
immediately to the left of the giant planet. The morning of Monday
the 25th, it will make a charming sight to the right of the Pleiades of Taurus, while the following morning
it will sit just above Aldebaran and the Hyades, which makes Taurus's vee-
shaped head. Then the next morning, that of Wednesday the 27th,
the Moon rather dramatically approaches
Mars (appearing just to the right of the planet). Indeed it
will actually occult, or cover, Mars, the event sadly visible only
from the South Pacific and South America.
Though still a morning object, as the month ends lordly Jupiter, in
the southwestern corner of Aries,
rises just after midnight Daylight Time. Not
quite three hours later, up comes reddish Mars, which lies between
the tips of Taurus's horns. In the so-far neglected evening, find
Saturn, but look early, as the ringed planet, still
to the northwest of Virgo's Spica, is down by 11:30 PM Daylight. If
your preference is the morning though, in addition to admiring
Jupiter and Mars, look for a few of the meteors of the Southern Delta Aquarid shower, which peaks
near the end of the month and appears to radiate from the
constellation Aquarius.
We are in the season for the Milky
Way. Under a dark sky in late evening, it pours out of Cygnus (with Deneb, nearly overhead at midnight),
brightening as it plunges southward into Sagittarius and the Galactic center.
