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The Sky This Week, 2014 August 26 - September 2

Fine sights for summer's last nights.
M4_140705_01small.jpg
Globular Cluster Messier 4 in Scorpius, with the bright star Antares
and the smaller globular cluster NGC 6144

Imaged from Morattico, Virginia, USA
with an 80mm (3.1-inch) f/6 Antares Sentinel refractor and Canon EOS Rebel T2i DSLR

The Moon waxes in the evening sky this week, scudding along the southern reaches of the ecliptic and into the bright starfields of the summer Milky Way.  First Quarter occurs on September 2nd at 7:11 am Eastern daylight Time.  Look for Luna some two degrees east of the bright star Spica low in the southwest about an hour after sunset on the 29th.  Two nights later she forms an attractive grouping with the planets Mars and Saturn.  On the evening of the 1st you’ll find her just over a degree north of the star Graffias, the northernmost of the three stars that form the “head” of Scorpius.

For the first few evenings of the week you’ll have another great opportunity to get to know our home galaxy, the Milky Way.  All week long Luna sets before midnight, and at that time the gauzy glow of our fellow galactic stars will bisect the sky for viewers in dark locations.  Take advantage of the last long weekend of the summer to view this wonderful sight with whatever you have at hand, be it a telescope, binoculars, or your unaided eye.  The naked-eye view inspired much lore among ancient people.  To the ancient Greeks it represented milk spilled from the breasts of the goddess Hera while nursing the infant Heracles.  The Inuit see it as “The Pebbly River”, with the stars of the constellation of Cygnus representing a man in a kayak paddling between the bright “stones”.  Binoculars begin to reveal its true nature as an unbounded sea of stars, especially through the vast star clouds found off the western tip of the “teapot” asterism in the constellation of Sagittarius.  You’ll also see clumps of brightness interspersed among the countless stars; examination of these with small to modest telescopes will show them to be clusters of stars and bright clouds of glowing hydrogen gas fluorescing from the radiation of hot newborn stars in their hearts.  Take note as well of the many dark rifts and patches interspersed among the star clouds.  These are especially prominent from southern hemisphere locales, where they were seen as “anti-constellations” by the ancient Inca people.

Early in the evening spend some time looking at the waxing Moon, especially on the evening of the 31st.  You won’t have to move the telescope very far to enjoy Luna along with Mars and Saturn, which will form a nice grouping in the southwest as evening twilight falls.  Take a moment to examine each object in turn and compare their apparent sizes.  The Moon will show exquisite detail on her battered face, while Mars will be little more than a tiny pink dot, scarcely bigger than the smallest visible lunar craters.  Mars is about twice the size of the Moon, but he’s some 500 times farther away.  Saturn will show a more generous disc, but his special feature is his magnificent system of rings, which should be easily visible in any telescope.  Saturn is over 7.5 times farther away from us than Mars, and the distance across his rings is over 70 percent of the distance from the Earth to the Moon!  They form the flattest and thinnest structure in the solar system with a thickness of one or two hundred meters.

As the Sun steadily rises later each morning you don’t have to get up at “oh-dark-thirty” to admire the bright planets of the morning sky, Venus and Jupiter.  If you’re up by 6:00 am you should be able to spot them in the eastern sky despite the glow of twilight.  If you don’t mind rising a bit earlier, you’ll also see the rising stars of the Great Winter Circle make their entrance to the sky.  It won’t be very long before the glow of the summer Milky Way will be replaced by the fixed glimmers of these bright stars.

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