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The Sky This Week, 2020 May 12 - 19

That hole in the sky is far from empty.
NGC4565, the 'Needle Galaxy in Coma Berenices, imaged 2020 April 21 from Alexandria, Virginia.
NGC4565, the "Needle Galaxy", an edge-on spiral galaxy in Coma Berenices,
imaged 2020 April 21 from Alexandria, Virginia
with a 10.2-cm (4-inch) f/6.5 Explore Scientific AR102 refractor
and a Canon EOS Rebel T2i DSLR.

The Moon graces the early morning sky this week, waning through her crescent phases as she wends her way northward through the barren autumnal constellations.  New Moon occurs on the 22nd at 1:39 pm Eastern Daylight Time.  Look for the Moon near ruddy Mars before dawn on the morning of the 15th.  Luna will be about four degrees southwest of the red planet.

As the Moon slips into the early morning sky we are now presented with a transition from the bright stars of winter to the more subdued constellations of spring.  Gone are the flashy, colorful luminaries of the Great Winter Circle and the bright constellations that host them.  Instead, we are presented with dimmer star patterns that can often be difficult to perceive from urban and suburban skies.  For me, the season has two “signature” constellations and a couple of bright stars, a far cry from the likes of Orion, whose outline can be seen from under just about any kind of inner-city sky.  Despite their lack of overly-bright stars, though, the patterns that form the constellation of Leo the Lion and the asterism we call the Big Dipper can be easily traced from most open spaces.  Leo crosses the meridian between 9:00 and 10:00 pm and is distinguished by the bright star Regulus, which sits at the bottom of a subset of stars commonly called The Sickle.  To the east the rest of the Lion is made up by stars forming a right triangle.  Opposite Leo in the northern sky, the seven stars of the Big Dipper reach their highest position in the sky, making the Dipper appear to pour its contents down to the northern horizon.  If you follow the “arc” of the Big Dipper’s “handle” you will run into springtime’s brightest star, Arcturus, and continuing to the south you will “speed on to Spica”, the blue-tinted star leading the constellation of Virgo.  

Suburban skywatchers will probably notice a large “hole” in the sky bounded by Regulus, Arcturus, and Spica, but if you venture away from the city that hole begins to fill in.  Just east of the triangle that forms Leo’s hindquarters, a large sprinkling of faint stars reveals the constellation Coma Berenices, the Hair of Queen Berenice II of Egypt.  This constellation was created by the court astronomer of Berenice’s husband, King Ptolemy III, one of the few extant star patterns named for an historical figure.  The scattered stars of this group, which number about 60 to the limit of naked-eye visibility, are all members of a nearby star cluster some 288 light-years away.  Despite its rather bland appearance, though, this area of the sky holds much more than meets the eye.  Beyond the stars of the nearby cluster, we don’t have to travel too far to leave the realm of our home galaxy, the Milky Way.  Now we are truly in a great void, but not for long.  Gazing in this direction brings hundreds of faint external galaxies into view, part of what is now known as the Coma-Virgo cluster of over 1000 galaxies averaging some 60 million light-years’ distance.  Our Milky Way is a far-flung member of this group.  Even more distant among Coma’s faint stars is the Coma Supercluster of nearly 10,000 galaxies, residing over 300 million light years away!

Much closer to home, the brilliant glow of Venus can be seen during the early evening, but her dazzle won’t be around much longer.  She is now racing to pass Earth on her faster inner orbit of the Sun, so she is now getting lower in the western sky each night.  She spends much of the week near the second-magnitude star El Nath, and if you watch her in binoculars you will see her gradually separate from the star.  Before she leaves us, though, she will have a close encounter with her inner solar system companion Mercury.  More on this next week.

Jupiter and Saturn are still best seen in the hours before sunrise, where you will find them gracing the southeastern sky.  Jupiter far outshines his more distant companion, but the pair should be very easy to spot as morning twilight gathers.

Mars gets a visit from the Moon early in the week, then continues his course through the faint stars of Aquarius.  You should have no trouble spotting his warm glow in the southeast as he steadily inches his way along the ecliptic.  

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