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The Night Sky of June

Dr. Wayne Wooten
Professor of Astronomy

For June 2013, the Moon will be new on June 8th, so the first week fins the moon waning in the morning sky. On the 10th, the thin waxing crescent moon passes about 5 degrees south of the Venus-Mercury pairing in the SW sky. Venus is on bottom, but much brighter than Mercury to the upper left of it. The first quarter moon is high up in the south at sunset on June 16th and appears high lit. The waxing gibbous moon passes seven degrees south of Saturn in the SE on June 20th. The beginning of summer occurs at 12:04 AM CDT on June 21, the longest day of the year, with about 14 hours of daylight for the Gulf Coast. Full moon, the Honey Moon, is June 23rd. This full moon occurs very close to perigee, when the moon is closest to Earth, so if you think it is bigger than normal, you are right! Note also this creates Spring Tides, with the sun and moon aligned to produce very high and low tides. The last quarter moon is on June 30th.

As June starts, you may just spot Jupiter below Venus on June 1st. Jupiter is about to get lost in the sun’s glare, so look about 30 minutes after sunset. You may wait until Jupiter sets to spot fainter Mercury to the upper left of Venus. All three are in a straight line on June 2nd, a great but challenging photo opportunity. Jupiter is lost in the sun’s glare by June 10th, when we have the nice grouping of the crescent moon just south of Venus and Mercury. Mercury is by then overtaking Earth, and retrograding westward toward the Sun, while Venus is moving higher in the evening sky, to dominate it for the rest of this year. Mercury passes to the lower left of Venus on June 17th, but the faint, thin crescent may be hard to spot naked eye by then. Mars gradually moves into the morning sky in June, low in the dawn sky.

High up in the southern evening sky is the most beautiful planet, Saturn, well east of Spica, the brightest star of Virgo. Saturn is brighter than Spica, and more yellow in color. Saturn’s rings are now open about 17 degrees; they will continue opening up wider until 2017, when they are tilted 27 degrees toward us and the Sun. You may also see some belts and zones on the planet’s disk. The largest, Titan, will be seen in any small telescope, but others will need larger scopes to spot.

The winter constellations are being swallowed up in the Sun’s glare, but you might spot Sirius low in the SW as June begins. Sirius vanishes into the Sun’s glare by mid-June, and this sets the period as "Dog Days", when Sirius lies lost in the Sun’s glare. In reality, Sirius is about 20x more luminous than our star, but also lies eight light years distant, while our star is eight light minutes away from us.

The brightest star in the NW is Capella, distinctively yellow in color. It is a giant star, almost exactly the same temperature as our Sun, but about 100X more luminous. Just south of it are the stellar twins, the Gemini, with Castor closer to Capella, and Pollux closer to the Little Dog Star, Procyon. By the end of June, all the winter stars, like Sirius, are vanished behind the Sun.

Overhead, the Big Dipper rides high. 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.

If you drop south from the bowl of the Big Dipper, Leo the Lion rides high. Note the Egyptian Sphinx is based on the shape of this Lion in the sky. 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, then 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.

To the east, Hercules is rising, with the nice globular cluster M-13 marked on your sky map and visible in binocs. This rich cluster is one of the top telescopic sights in good sized scopes. This fine photo of M-13 is by EAAA member Rick Johnston approximates how it appears through a six inch telescope at 100X. Several other good globular clusters are also shown and listed on the best binoc objects on the map back page.

The brightest star of the northern hemisphere, Vega (from Carl Sagan’s novel and movie, "Contact"), rises in the NE as twilight deepens. Twice as hot as our Sun, it appears blue-white, like most bright stars. Its constellation, tiny Lyra, looks like a parallogram just south of Vega, but was the harp of Orpheus in Greek legends.

In the southeast, Antares rises about the same time as Vega does, in the brightest of all constellations, Scorpius. Antares 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!

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