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The Night Sky of August

Dr. Wayne Wooten
Professor of Astronomy

For August 2014, the first quarter moon passes two degrees north of Mars on August 3rd, and will occult Saturn for all of Australia on August 4th, but we will only see a close miss here. The full moon, the Green Corn Moon in American Indian tradition, will be on August 10th and thus interfere badly with the peak of the Perseid meteor shower on the mornings of August 12-13th this year. The moon is last quarter on August 17 and rises about midnight. The waxing crescent moon passes five degrees south of Jupiter and Venus in the dawn sky on August 23rd, and is new on August 25th. The waxing crescent moon again occults Saturn on August 31st, but only in northern Africa does it appear after sunset. Here they will just be rising as it happens in morning daylight.

Mercury is not well placed for northern hemisphere viewers this month, lost in the sun's glare. Venus continues to dominate the morning sky, but is still on the far side of the sun, appearing as a bright, featureless gibbous disk in the telescope this month. She passes by Jupiter in the dawn on August 18, only .2 degrees north of the second brightest planet for one of the closest groupings of bright planets in your lifetime, so set you alarm clocks for this! Mars is fading on the far side of its orbit now. It catches and passes just 3.4 degrees south of Saturn on August 25th. Saturn lies in Libra now. Enjoy the rings, now 20 degree open and tilted toward earth and sun; the most beautiful planet falls closer to the western horizon each evening, to be lost in the sun's glare in September.

The Big Dipper rides high in the NW at sunset, but falls lower each evening. Good scouts know to take its leading pointers north to Polaris, the famed Pole Star. For us, it sits 30 degrees (our latitude) high in the north, while the rotating earth beneath makes all the other celestial bodies spin around it from east to west.

Taking the arc in the Dipper's handle, we "arc" SE to bright orange Arcturus, the brightest star of Spring. Cooler than our yellow Sun, and much poorer in heavy elements, some believe its strange motion reveals it to be an invading star from another smaller galaxy, now colliding with the Milky Way in Sagittarius in the summer sky. Moving almost perpendicular to the plane of our Milky Way, Arcturus was the first star in the sky where its proper motion across the historic sky was noted, by Edmund Halley.

Spike south to Spica, the hot blue star in Virgo. From Spica curve to Corvus the Crow, a four sided grouping. It is above Corvus, in the arms of Virgo, where our large scopes will show members of the Virgo Supercluster, a swarm of over a thousand galaxies about 50 million light years away from us.

Hercules is overhead, with the nice globular cluster M-13 marked on your sky map and visible in binocs. It is faintly visible with the naked eye under dark sky conditions, and among the best binoc objects in the night sky.

The brightest star of the northern hemisphere, Vega dominates the NE sky. Binoculars reveal the small star just to the NE of Vega, epsilon Lyrae, as a nice double. Larger telescopes at 150X reveal each of this pair is another close double, hence its nickname, the "double double"…a fine sight under steady sky conditions.

Below Vega are the two bright stars of the Summer Triangle; Deneb is at the top of the Northern Cross, known as Cygnus the Swan to the Romans. It is one of the most luminous stars in our Galaxy, about 50,000 times brighter than our Sun. To the south is Altair, the brightest star of Aquila the Eagle. If you scan the Milky Way with binocs or a small spotting scope between Altair and Deneb, you will find many nice open star clusters and also a lot of dark nebulae, the dust clouds from which new stars will be born in the future

To the south, Antares rises about the same time in Scorpius. It appears reddish (its Greek name means rival of Ares or Mars to the Latins) because it is half as hot as our yellow Sun; it is bright because it is a bloated red supergiant, big enough to swallow up our solar system all the way out to Saturn's orbit! Just above the tail of the Scorpion are two fine naked eye star clusters, M-7 (discovered by Ptolemy and included in his catalog about 200 AD) and M-6, making one of the best binocular views in the sky. Your binoculars are ideally suited to reveal many fine open star clusters and nebulae in this region of our Galaxy.

East of the Scorpion's tail is the teapot shape of Sagittarius, which marks the heart of our Milky Way galaxy. Looking like a cloud of steam coming out of the teapot's spout is the fine Lagoon Nebula, M-8, easily visible with the naked eye. In the same binocular field just north of the Lagoon is M-20, the Trifid Nebula. Just east of the pair is the fine globular cluster M-22, faintly visible to the naked eye and spectacularly resolved in scopes of 8" or larger aperture. It lies just to the upper left of the star that marks the top of the teapot shape of Sagittarius, so it is easy to spot in binocs as well. Our featured shot of the month is of M-22, and you can see why it is one of our favorite objects to show the public in big scopes!

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