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The Sky This Week, 2017 November 28 - December 5

See the International Space Station!
Trail of the International Space Station
imaged from the U.S Naval Observatory in 2017 November 27, 22:44 UT.
20-second exposure with a Canon EOS Rebel T2i DSLR and a 24mm lens.

The Moon brightens the evening sky this week, waxing from the gibbous phase to Full Moon, which occurs on December 3rd at 10:47 am Eastern Standard Time.  December’s Full Moon is variously called the Cold Moon, Long Night Moon, or the Moon Before Yule.  It is usually the Full Moon that achieves the highest declination in the sky, thus providing a pale glimmer to the barren landscape below.  This year, however, the Cold Moon’s declination will be slightly bettered by the next Full Moon, which will fall on New Year’s Day.  However, both of these Full Moons occur near the time of the year’s closest perigees, so they will both appear a bit brighter than usual.

I often say that there aren’t many bright objects to look for during the early evenings in late autumn, but this week we’ll be treated to a particularly luminous, albeit fleeting, celestial object.  The International Space Station has been dutifully circling the Earth since 1998, and it has grown to a space outpost that’s almost as big as a football field.  When it passes overhead under the right lighting conditions its brightness can easily rival the bright glow of Venus.  We’ll be under those conditions here in the Washington area for several evening passes of the ISS this week.  The first good pass occurs on the 28th, when the Space Station rises in the west at around 6:26 pm EST.  It will pass close to the bright star Vega in the northeast, then head toward the star Polaris, the North Star.  It will vanish into Earth’s shadow near Polaris a little after 6:28 pm.  The week’s best pass occurs on the 29th, when the ISS appears in the southwest at 5:33 pm.  It culminates near the zenith at 5:35 pm, then heads off toward the northeast, drifting through the stars of Perseus and Auriga by 5:37 pm.  The week’s final good pass occurs on the evening of December 1st, when the Station follows a similar path to that of the 28th, rising in the west at 5:25 pm, passing just under Polaris at 5:28 pm, and setting in the northeast at 5:30 pm.  Each time you see it, remember that there are six human beings inside that brightly glowing dot, rotating in and out at six-month intervals.  If you don’t live in the Washington area, you can still see predictions for bright ISS passes at your location courtesy of the Heavens Above website.

The Moon presents a great target for the small telescope on the nights leading up to Full Moon.  With Luna reaching higher declinations in the northern sky she shines through less of our distorting atmosphere, often allowing scrutiny under your highest magnification eyepieces.  By the week’s end the Moon is placed among the rising stars of the Great Winter Circle.  If you find yourself up at midnight around the time of Full Moon you’ll have a feast for the eyes with Luna perched high above the bright stars of Orion, surrounded by the many-hued stars of the long winter’s night.

You’ll have to wait until the Winter Circle heels over in the west before there’s a bright planet to look at, and right now that planet isn’t particularly bright.  Mars begins the week just to the north of the bright star Spica in the constellation of Virgo.  As the week moves on, so does the red planet, leaving Spica in his wake.  At the moment Mars shines just above second magnitude, considerably fainter than the star.  His warm pink-hued glow distinguishes him from Spica.

Jupiter should be easily spotted in the southeastern sky as morning twilight begins to brighten the horizon.  The giant planet is gradually drifting toward the second-magnitude star Zubenelgenubi in the constellation of Libra, the scales.  Old Jove will pass the star shortly before Christmas, and Mars will overtake both during the first week of next year.

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