August 2008

Most of the planets have taken the summer off, leaving their king, Jupiter, to reign in solitary splendor.

Coming out low in the south above the Teapot of Sagittarius, the giant world commands attention as the brightest beacon in the evening sky. Its large yellowish orb glows like a drop of honey dripping from the Teaspoon, the Teapot's tiny and more northerly companion.

Next to Sagittarius, Scorpius rears its head and claws toward the west. The sinuous, well-named constellation is set off by one of the largest stars known: ruddy Antares, the heart of the scorpion.

The Milky Way makes a handy guide to other constellations as it slashes across the evening sky from northeast to southwest. Following this pale river of light up from Scorpius and Sagittarius, we encounter the bright star Altair in Aquila, the eagle; brilliant Vega in the parallelogram of stars known as Lyra, the lyre; and Deneb, the jewel of the Northern Crown in Cygnus, the swan.

Altair, Vega, and Deneb form the Summer Triangle of bright stars. Flanking the triangle to the east, the diminutive dolphin Delphinus leaps toward the Great Square of Pegasus, while to the west, heroic Hercules kneels upside down. West of Hercules, glorious Arcturus seems to drag kite-shaped Bootes, the herdsman, down toward the horizon.

Continuing our tour of the Milky Way past Deneb, the squiggle of stars called Lacerta, the lizard, is hard to distinguish except against very dark skies. Next comes the W- or M-shaped Cassiopeia, and finally Perseus, the constellation from which August's famous meteors radiate.

This year the best time to look for the Perseid meteors will be the predawn hours of the 12th. A plump gibbous moon will set around 1:30 a.m. local time, leaving a relatively dark sky for the fireballs and their often long, persistent trails. Perseus will then be high in the east, so meteors can be followed for long distances in any direction. Like most other meteor showers, the Perseids are best viewed from the comfort of a reclining lawn chair.

On the 16th, August's full moon undergoes a partial eclipse that ends before it rises over the Midwest. But when it does come up, the moon will be just a few hours past the point of perfect fullness and so pleasing to the eye. Many Algonquin Indian tribes called this the sturgeon moon to honor the once-abundant lake sturgeon, a large denizen of waters such as the Great Lakes and Lake Champlain that is most easily caught this time of year. Some tribes, noting the moon's color as it rose through hazy skies, called August's full moon the red moon, while others dubbed it the green corn moon.

Mornings in August and September are good times to see the elusive zodiacal light. Appearing as a faint, broad finger of light pointing up from the horizon, it may be glimpsed against very dark skies between two hours and one hour before dawn. It will be hard to see, however, between about the 15th and the 28th, when a bright moon is likely to interfere. The zodiacal light results from sunlight reflecting off particles of dust in the plane of the solar system.

The arrival of August may mean vacation to us, but to farmers it has long meant the first harvest of grain. To the ancient Celts, bread baked from this crop gave rise to a holiday called Lughnasaid (LOON-eh-sed), one of four cross-quarter days falling midway between a solstice and an equinox. The modern feast of Lammas (a corruption of "loaf mass"), celebrated August 1, stems from Lughnasaid but is less well known than its fellow cross-quarter days, whose English names are Groundhog Day, May Day, and Halloween.