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The Sky This Week, 2013 May 7-14

Planets gathering in the west, and galaxies galore overnight.
MarkarianChain_130414_01small.jpg
Markarian's Chain, the heart of the Virgo Galaxy Cluster.
Imaged from Morattico, VA 2013 APR 14 with a
80-mm (3.1-inch) f/6 Antares Sentinel refractor, iOpton "Cube Pro" mount,
and a Canon EOS Rebel T2i DSLR.  Digital "stack" of 16 30-s exposures at ISO 3200.

The Moon returns to the evening sky by the week’s end, slipping into the sky as a thin crescent.  New Moon occurs on the 9th at 8:38 pm Eastern Daylight Time.  Observers on the other side of the world will be treated to an annular solar eclipse at this time.  The path of this “ring of fire” sky show runs from northern and eastern Australia across the eastern tip of Papua New Guinea before heading out into the vast open waters of the central Pacific Ocean.  At its greatest extent the Moon will cover just over 95% of Old Sol’s disc, so there will be no chance of seeing the delicate features of the solar corona.  Once the Moon enters the local evening sky you can spot her 48-hour-old crescent just under 7 degrees below the Moon in the early evening twilight.  If you have a clear western horizon, look 9 degrees below and to the right of the Moon on this evening.  You may be rewarded with a quick glimpse of brilliant Venus, now slowly emerging from her recent solar conjunction

Clear skies seem to be at a premium these days, but if perchance the sky does clear this is another great week to “go deep” with telescopic observing.  The absence of the Moon means that it is prime time to hunt down faint, distant galaxies that haunt the space behind the constellations of spring.  By now most of you should be able to recognize the Big Dipper and Leo in the mid-evening sky, and the bright star Arcturus now dominates the eastern sky with its rose-tinted glow.  Farther to the south you’ll run into the bright blue star Spica and the golden hue of Saturn, which form a nice triangle with Arcturus.  The general part of the sky that’s bounded by these familiar stars is well-known to amateur astronomers as the “Realm of the Galaxies”, because it is here that you will find the center of the Virgo Galaxy Cluster.  Located some 55-60 million light-years away from us, there are hundreds if not thousands of galaxies associated with the group.  It is even though that our Milky Way galaxy is a far-flung member.  Hundreds of these external star cities are visible to large amateur telescopes, and many of the brighter ones can be glimpsed in very modest instruments.  If the weather is clear on Saturday, May 11th, you can explore some of these distant places with members of the Northern Virginia Astronomy Club (NOVAC) at their annual Astronomy Day event at Sky Meadows State Park near Paris, VA.  While the park charges a per-car parking fee, the events get under way at 3:00 pm with safe solar viewing, guest speakers, and a chance to see what amateur astronomy is all about.  Details may be found on the Club’s website.

Bright Jupiter now peers at me for a few minutes between the roofs of nearby houses.  He is still easily found in the gathering twilight, but his low altitude makes him almost impossible to observe with the telescope.  Fortunately he will soon be joined by bright Venus in the twilight sky, and as May ends and June opens Mercury will join the fray.  We might not get our best telescopic views of the giant planet at this time, but there will be ample time for interesting photo opportunities with more conventional gear over the next several weeks.

Golden Saturn now comes into view about 45 minutes after sunset in the southeastern sky.  The planet passed opposition 2 weeks ago, so he’s in the sky all night long.  By now you may notice that his rings don’t seem to be quite as bright as they were around opposition.  The small phase angle that’s now growing with each passing evening reveals more and more of the shadow texture of the particles in the rings, causing them to appear a tad dimmer.  You’ll have to wait for a very still night to fully appreciate the detail in the planet’s ring system.  His southerly declination subjects him to more atmospheric turbulence and extinction, but on nights when the “seeing” is good you can’t find a more exotic sight in all the heavens!

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