August 2005

by Deane Morrison

Now that July's fireworks are over, we can get ready for August's. The Perseid meteor shower will arrive on schedule during the second week of August, reaching a peak around noon on the 12th. We won't see anything at that time, of course, but on the night of the 11th-12th, the moon will have set by the time the constellation Perseus rises and the meteors start flying. Get comfortable and watch for fireballs hurtling through the sky from the northeast. The Perseids represent the burnup of dust particles left behind by Comet Swift-Tuttle, a comet that visits our part of the solar system every 130 years. The dust hits our atmosphere at speeds close to 132,000 mph, sparking bright streaks that often leave a persistent trail.

While you're watching the meteors, take a look at all the summer constellations arrayed before you. Quite a few are in or near the Milky Way, which stretches from northeast to southeast in the evening hours. Starting in the northeast, with Perseus, follow the faint river of light through W-shaped Cassiopeia; the Summer Triangle of Deneb, Vega and Altair; and, low in the south-southwest, Sagittarius with its Teapot and Scorpius with its red heart, the bright star Antares. In the west, brilliant Arcturus leads Bootes, the herdsman, toward the horizon. To the east, the Great Square of Pegasus enters the sky.

Looking west after sunset, you'll see Venus somewhat low but still bright. Jupiter, also low in the west, steadily closes in on Venus; by month's end the two will make a nice pair.

Saturn recently became a morning planet, and by the end of August it rises about three hours before dawn. It has forsaken Gemini and is now heading toward the Beehive star cluster in Cancer.

Mars, only two months away from its next close approach to Earth, keeps rising earlier and appears before 11 p.m. by the end of August. Already as bright as most of the brightest stars, Mars is just starting to crank up the wattage. If you have a telescope, wait until the predawn hours, when Mars will be high enough for good viewing.

The full moon of August, called the green corn moon or the grain moon, arrives at about 1 p.m. on the 19th, so it's a tossup whether it's better to look for it the night before or the night after. A new moon occurs on the 4th.

August and September are good times to look for the zodiacal light, a broad, faint finger of light pointing up from the horizon along the sun's path through the sky an hour or two before dawn. It comes from reflections of sunlight off dust in the plane of the solar system.

The feast of Lammas, celebrated the first of August, began as a Celtic holiday called Lughnasaid (LOON-eh-sed). It was one of the Celtic world's four cross-quarter days, which fall midway between a solstice and an equinox. Its more famous cousins are Imbolc (Groundhog Day), Beltane (May Day) and Samhain (Halloween). Lughnasaid was a harvest festival featuring bread baked from the new crop of grain. The Christian Church adopted the holiday as the Loaf Mass, which was eventually corrupted to Lammas.