Perseid Meteor Shower
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AUGUST 2006 SKYWATCH The highlight of the August night sky is the Perseid meteor shower on August 12-13. Comet Swift-Tuttle has been passing through the inner solar system for centuries, spreading dust along its orbit and delighting watchers. Every year at this time, Earth passes through that orbit, and we have a sky show, some years very spectacular. What we see is the friction of these dust particles as they enter the earth’s atmosphere at 37 miles per second, and burn up. The typical meteor is produced by a particle no larger than a pea, and no particles from a meteor shower ever fall on earth, say astronomers. They burn up too quickly. Full Moon falls on August 9, so the night sky is still too bright for prime viewing by the 12th. Nevertheless, the Perseid shower is usually abundant, and its meteors are bright, so we still might see a good show. Check out the nights of August l3-14 as well, for we will still be experiencing the Perseid shower. In fact, the shower lasts from about July 30- August 25. So keep your eyes on the night sky this month, especially later at night, and especially when the sky is darker. In the early evening of August 12 (a Saturday), set up a chair outdoors facing east. Look a third to a half way up in the sky. After the moon rises, turn your chair away from the moon, and look overhead. The moon will be moving westward as the meteor shower climbs, and peaks. To see that peak, about 2 a.m. turn your chair back to the east, and concentrate on an area of sky about halfway up, the vicinity of the constellation Perseus. How many meteors can we see? Perseids have a high count of 110/hour at the zenith on a dark sky night. However, under these conditions of more light, we can expect to see from 20-30 meteors/hour, still a treat. Planetary viewing is close to the horizon this month, in evening twilight, or in morning twilight. Brilliant Jupiter is still visible in the southwest. The moon passes close to it on August 1 and on August 29. Mars now is faint, and will disappear below the horizon by the end of the month. Perhaps we can spot it with a new crescent moon on August 25. Saturn is below the horizon, hanging out with Sun. We can’t see it again until later in the month, when it rises in the morning. Watch the early morning sky, especially in the latter part of the month, for the real action. Mercury, Saturn, and Venus all rise close together in the dawn sky by the third week of August. They make a beautiful trio. The old crescent moon adds magic on the morning of August 21, when it passes just above Venus, the highest of the three. On August 22, the wafer-thin crescent moon passes just to the left of Saturn, and just above Mercury. On August 23, perhaps in the dawn we can see the ghost of the old moon being incorporated into the sun, to become a new moon. |
