August 2007

by Deane Morrison

Low in the south, Scorpius stretches its S-shaped body and claws westward. Behind it, the Teapot of Sagittarius, the archer, is perpetually poised to pour its contents on the arachnid's tail. Hovering above Antares, the heart of the scorpion, Jupiter adds a brilliant accent to the pair of summer constellations. The king of planets, with its slightly yellowish hue, contrasts well with the ruddy complexion of Antares.

Antares, a red supergiant star, is nearing the end of its life. It has swelled up to almost unimaginable size--700 times the diameter of the sun--and shines with the brightness of 10,000 suns. Yet its mass is only 15 times as great as our parent star. Although about 500 light-years away from us, Antares rivals Mars in brightness and color, and, in fact, bears a name meaning "rival of Mars." Someday, it will light up our sky as it explodes in a gargantuan supernova.

Speaking of the Red Planet, it glides eastward through the stars of Taurus this month. On the 21st, it will be high in the east-southeast in the predawn sky, below the Pleiades cluster and close above the V-shaped Hyades, which outlines the face of the bull.

Thanks to a new moon on the 12th, this should be a great year for viewing the famed Perseid meteors. The shower peaks between midnight and the early morning hours the night of the 12th-13th. Perseids are usually bright and fast, and often leave persistent trails. So get yourself a lawn chair, lie back, and look to the northeast.

Early risers will be treated to a spectacular total lunar eclipse the morning of the 28th, when the full moon plows through Earth's dark inner shadow, or umbra. The moon first touches the umbra at 3:51 a.m. CDT and reaches deepest eclipse at 5:37 a.m. For us, the eclipse will be cut short around 6:37 a.m., when the moon sets with much of its disk still shrouded in umbra.

Algonquin Indian tribes called August's full moon the green corn moon or the sturgeon moon, after the Great Lakes fish that is most easily caught in late summer. This year it follows a low trajectory across the sky in Aquarius, the water bearer.

Another early morning treat for viewers with clear, dark skies is the elusive zodiacal light, visible in August two hours to an hour before dawn. This faint cone of light comes from reflections of sunlight off dust left by meteors in the plane of Earth's orbit.

The month of August may seem slow and stultifying to us, but to ancient and Medieval people it brought hope and renewal. In August the first harvests were reaped, and having bread baked from the new crop was cause for celebration. The feast of Lammas, celebrated August 1, began as a Celtic holiday called Lughnasaid (LOON-eh-sed). It was one of the Celtic world's four cross-quarter days, falling midway between a solstice and an equinox. The other cross-quarter days are Imbolc (Groundhog Day), Beltane (May Day) and Samhain (Halloween). The Christian Church adopted the holiday as the Loaf Mass, which was eventually corrupted to Lammas.