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The Night Sky of August

Dr. Wayne Wooten
Professor of Astronomy

For August 2022, the first quarter moon occurs on August 5th. The famed Perseid meteor shower is dimmed this year by the full moon, the Thunder Moon, occurring on August 11th, the day before the shower’s peak the next morning. The moon lies four degrees south of Saturn the same evening; Saturn is at opposition, rising at sunset, only three days later. On August 15th, the waning gibbous moon passes two degrees south of Jupiter in the dawn. The moon is last quarter on August 19th, and lies three degrees north of red Mars. The waning crescent lies just above Venus dust before dawn on August 25th. It is new on August 27th.

Mercury is too close to sun for viewing this month until the end of August, when the axing crescent passes seven degrees north of it on August 29th. Venus is about to be lost in the Sun’s glare at superior conjunction for several months, and appears just before the dawn, getting lower and lower each morning. Mars is in the dawn in Taurus, and gets brighter as the earth is overtaking it and closing in on it. Jupiter is Pisces, rising about two hours after sunset by month’s end, and will reach opposition in September, back in the evening sky for the rest of 2022. Saturn reaches opposition on August 14th, closest to earth and brightest in the evening sky. The north pole of Saturn is tilted 14 degrees toward earth now. What a sight in any telescope! Note the Cassini Division, where the rings split, and the shadow of the planet on the rings.

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. 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 (to the north) and Altair. 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. It sits atop the Cross, and lies in a region where new stars and born and old stars die literally in front of our eyes! I was lucky enough to discover one such stellar death, Nova Cygni 1975, on August 27, 1975. It peaked at magnitude +1.8, the sixth brightest star of the summer sky, in two days, but faded below naked eye visibility in just two weeks, alas. A far grander supernova some 15,000 years ago happened SE of the eastern wing of the Swan, epsilon Cygni. The Veil Nebula is faintly visible in big binocs and wide field scopes under very dark skies, but a colorful photographic target. Look to the west at brilliant Venus, and imaging transposing it overhead to the wing of Cygnus; how our ancestors must have been awed by the sudden and perplexing change in the changeless stars! Far more material was blasted out into space than in my nova, and the shock wave from this supernova, now spanning three degrees (six moon diameters), continues expanding at a million miles per hour.

To the south is the southernmost member of the Triangle, 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. Father south of Altair, we find the glorious "Pillars of Creation". They lie in the center of the much larger Earle Nebula, marked M-16 on your SkyMap. It is visible faintly in binoculars, and is lit by the ultraviolet radiation of the hot young stars just condensing in the densest central region of the nebula here. The red is ionized hydrogen, with dark dust lanes marking the profile and "feathers" here.

To the southeast, Antares is bright in the heart of 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. Get a dark sky site, and use the objects listed on the back of the August 2022 SkyMap printout to guide you to the best deep sky wonders for binoculars and small telescopes.

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. Above it is the Trifid Nebula, M-20, another fine and very colorful stellar nursery. Just east of these young star birthplaces is the fine globular cluster M-22, faintly visible to the naked eye and spectacularly resolved in scopes of 8" or larger aperture. Look just east of the top star in the teapot of Sagittarius with binoculars.

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