Stars over Sisters

The month of August brings with it the highly reliable, sometimes spectacular, Perseid meteor shower, one of the astronomical highlights of each year.

The shower occurs when the earth travels through debris left behind by comet Swift-Tuttle. While these meteors can be seen from July 17 through August 24, this year's shower will peak on the night of August 12 into the early morning hours of August 13. Normally, observers can expect to see about 60 meteors per hour, but this time around a waning gibbous moon will wash out some of the fainter streaks of light.

While the radiant point of the shower is the constellation Perseus, located in the northeastern sky near Cassiopeia, meteors will streak across all parts of the sky. The best time to view the shower is between about midnight until dawn from a dark location. For those who can't stay up late, mid-evening is the best time to catch what are known as an "earth grazers" - memorable meteors that are elongated and linger across the sky.

As night falls early in August, the southernmost constellation of the zodiac, Scorpius the scorpion, pops into view. To find it look low in the southern sky, about 15 to 20 degrees above the horizon. Scorpius actually looks like a scorpion-the stars in the asterism make a J-shape, like a scorpion's tail. Antares, the thirteenth brightest star in the sky, marks the scorpion's heart. Antares is a red supergiant star, having a radius of three AU (astronomical units), three times the distance between the earth and the sun.

In Greek mythology, Scorpius' story is intertwined with that of Orion's. Orion had bragged that he could kill every animal on Earth, and set out to do so. However, the Earth goddess didn't want him to harm her animals, so she sent a scorpion to deal with him. After stepping on the scorpion, Orion died. The king of the gods, Zeus, later placed both the scorpion and Orion in the heavens, but at opposite ends of the sky. Therefore, when Scorpius sets in the fall, Orion will begin to rise.

Since Scorpius' tail dips into the Milky Way, many deep-sky objects are found here. These include the fine open star clusters M6, the Butterfly Cluster, and M7, Ptolemy's Cluster, and are found near the stinger on the scorpion's tail. There are also two prominent globular clusters in Scorpius. M4, located just west of Antares, is one of the closest globular clusters to our solar system. M80 is about 95 light-years in diameter and contains several hundred thousand stars, making it one of more densely populated globular clusters in the Milky Way galaxy. A nova was discovered here in 1860.

This month, the moon is in its first quarter on August 3, last quarter on August 17, and new on August 25. The full moon on August 10 is the closest and largest full moon of the year. This is because the moon is at perigee (closest point in the moon's orbit to the earth) when the sun and moon are at opposite locations in the sky (full lunar phase).

The bright pair of planets, Venus and Jupiter, will be visible in the east before sunrise in August. Mars is still visible in the western sky during the evening, residing in the constellation of Virgo. Mars has a reddish color, making it recognizable next to Virgo's brightest star, Spica, which is a blue-white color. Saturn is visible to the east of Mars and Spica during the evening hours, as well.

To learn more about the night sky, join the Sisters Astronomy Club on Friday evening, August 29 for its Stars over Sisters star watch event. The program will take place at Sisters Park & Recreation District beginning at 8 p.m. Telescopes will be provided through which to view the wonders of the heavens.