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The Sky This Week, 2011 October 11 - 18

Something to hang your coat on...


Jupiter & Ganymede, 2011 OCT 10, 04:05 UT
Imaged with a 20-cm (8-inch) Schmidt-Cassegrain telescope
from near Morattico, VA.

The Moon dominates the evening sky view as the week opens. She rises before midnight every night as the week progresses, waning to Last Quarter phase on the 19th at 11:30 pm Eastern Daylight Time. Look for Luna close to the bright planet Jupiter on the evenings of the 12th and 13th. On the 14th and 15th she passes to the south of the rising Pleiades star cluster. Also on the 15th, look for the bright ruddy star Aldebaran about six degrees below the Moon’s silvery disc. Hopefully many of you had a chance to view the Moon last weekend during International Observe the Moon night. For a change the weather cooperated and gave us a near-perfect evening. The next great chance we’ll have to share the Moon through a telescope will be Halloween, when a waxing crescent will be available to show to neighborhood Trick-or-Treaters.

With the passing of the Moon to later hours we once again find the early evening as prime time to do a little "deep-sky" observing. As the fall foliage begins to peak, many of us will head to the mountains to enjoy the fall colors. Take along your binoculars for viewing some of the treats of the late summer sky as the Milky Way appears after the end of evening twilight. There are many star clusters and glowing nebulae to catch your attention as you slowly sweep the Galaxy’s amorphous glow. One of my favorite binocular targets lies about one-third of the distance from the bright star Altair to the brighter star Vega along one of the sides of the Summer Triangle. Take a leisurely sweep of this part of the sky to see a small asterism that resembles an upside-down coat-hanger. Like many amateurs before me I "discovered" this object accidentally while looking through binoculars. It is not usually plotted on basic star charts, so it often surprises those who find it. Known formally as Collinder 399, the "Coat-hanger Cluster" is one of the best examples of objects that look best in binoculars. While it is best seen from a dark sky, it can be easily spotted from the suburbs as well.

If you look to the west shortly after sunset you may notice a persistent bright point of light in the twilight glow. Resembling the landing light of a distant airplane, this is really the glimmer of the planet Venus, which is slowly emerging into the evening sky. I had my first glimpse of the returning planet this past weekend looking over the Rappahannock River from Virginia’s Northern Neck. Venus will linger over the twilight horizon until late November, then she will climb rapidly to grace the evening sky by the end of the year.

Where Venus requires a bit of work to find, Jupiter is easy to spot once he rises. The giant planet now crests the horizon before 7:30 pm, and by 9:00 pm he’s easily seen in the east. By 10:00 he’s high enough to train the telescope on his swirling cloud tops and shuttling moons without looking through too much of our turbulent atmosphere. With last week’s break in our rather gloomy fall weather I spent many hours at the eyepiece watching Old Jove’s subtle details rotate through the eyepiece of my telescope, and the show is only going to get better. Jupiter reaches opposition on the 28th and will be around to delight us well into next year.

One more planet awaits your view, but at the moment he’s playing a distant second fiddle to Jupiter. Ruddy Mars rises a bit before 2:00 am EDT and spends the week drifting eastward between the scattered stars of Cancer and the distinctive outline of Leo. Mars currently appears as a tiny pink-hued gibbous in the telescope, but his strong ruddy color makes him a standout in the pre-dawn eastern sky.

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