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The Sky This Week, 2016 August 30 - September 6

Take a holiday among the stars.
Venus & Jupiter in close conjunction (with interloper)
imaged 2016 August 27 from Alexandria, Virginia

The Moon returns to the evening sky this week, gracing the twilight hours with a gradually growing crescent. New Moon occurs on September 1st at 5:03 am Eastern Daylight Time. If you have a flat western horizon and a good clear sky try to sight the very slender crescent Moon just half a degree from Jupiter. You’ll probably need binoculars to make this sighting as the duo will only be five degrees above the horizon about 20 minutes after sunset. On the following night you should be able to find the Moon about six degrees to the east of Venus and see both objects with the unaided eye. By the evening of the 6th Luna will be about four degrees above the star Zubenelgenubi in the constellation of Libra, the Scales.

The upcoming holiday weekend offers vacationing skywatchers a fine way to say farewell to summer. Whether you’re in the mountains or at the shore the opportunity to be away from city lights offers splendid views of the season’s signature constellations and the most luminous parts of the Milky Way that we can see from the Northern Hemisphere. By 10:00 pm the summer Milky Way glimmers high in the sky, bisecting the celestial sphere from the southwest to the northeast. The Galaxy’s densest star clouds may be seen to the south, just off the "spout" of the "Teapot" asterism formed by the brighter stars of the constellation Sagittarius. If you have binoculars handy, use them to gradually sweep the Milky Way from the horizon to the zenith. You’ll be surprised at the number of luminous knots strewn about the clouds of innumerable stars that the binoculars will reveal. Also notice the seeming "voids" among these star clouds. Hundreds of these were discovered and catalogued by the great American astronomer Edward Emerson Barnard in the early 1900s. They are not real voids, but rather obscuring clouds of cold, dark gas and dust that may someday form new stars and planetary systems. So too is the "Great Rift" that bisects the Milky Way as it passes through the bright stars of the Summer Triangle, which lies directly overhead in the late evening. If you have a telescope, re-trace your binocular steps to view star clusters, glowing gaseous nebulae, and millions of faint background stars. You don’t need a large telescope for this; a small-aperture low-power instrument is ideal for this kind of exploration.

The evening twilight hour finds the bright glimmer of Venus low on the western horizon. Fresh from her close encounter with Jupiter on the 27th, she rapidly outpaces the giant planet, gradually climbing a bit higher each night. You’ll find her sharing the limelight with the slender crescent Moon on the evening of the 3rd.

If you’ve been following ruddy Mars over the past few weeks you will have watched him pass by the star Dschubba, then between the planet Saturn and the star Antares. He is now crossing the Milky Way’s densest star field and should offer a wonderful sight in the low-power telescope as his bright ruddy hue contrasts with the blue-white background stars.

Saturn has now been passed by ruddy Mars and is slowly creeping eastward above the star Antares. You can get a decent view of him in the telescope as soon as he pops out of evening twilight, and he should remain high enough to show his distinctive rings for a couple of hours before he sinks toward the southwest horizon.

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