AUGUST  1997

049    AUGUST 3, 1997:   Observing Meteors

Now that your meteor gear is assembled (see last week’s StarWatch), you’re ready to try catching some Perseids. Pick a location with good horizons, and set up facing the northeast. Perseid meteors will appear to radiate from the constellation of Perseus, the Hero, which becomes prominent after midnight. Plan on at least 2-3 hours of observing. For the first hour, just watch. Around midnight Perseids seem to diverge from a location in the NE, about a third of the way up in the sky. They move swiftly; some are very bright, and many leave trains, an afterglow of luminescent air after the flash. Keep your own hourly counts. Break for no more than 10 minutes/hour of observing. Rates increase after midnight as the Earth rotates us forward so that we plow into the bits of cometary debris which result in creating Perseid meteors. Perseid rates will be greatest on the morning of August 12. Photographing the Perseids next week...

050    AUGUST 10, 1997:   Photographing Meteors

Perseid meteors will fly after midnight on the mornings of Tuesday, August 12th and Wednesday the 13th, and in lesser amounts thereafter. Moonset on the 11th is at 11:30 p.m., and 1:12 a.m. on the 13th. To photograph the Perseids, use an SLR camera, 50 mm lens set at F/2.0-F/2.8, and a relatively fast film such as Royal Gold 400 for color or Tri-X for b/w prints. A tripod and cable release are necessary to control exposure times and motion. Set your shutter speed to bulb, "B" and with your cable release, lock your shutter open for periods of no more than five minutes. Point your camera straight up. You may need a hair dryer to warm your lens occasionally between shots so that dew does not condense on the glass. For point and shoot cameras, contact Tim Miller at Dan’s Camera City--610-434-2313. Some Pentax models and others have a "B" setting, but many will not be adaptable. Clear skies!

051    AUGUST 17, 1997:   Day of the Full Moon

The moon begins the week nearly full, but technically doesn’t reach the full phase until 6:55 a.m. EDT Monday. By that time the sun has risen over the Lehigh Valley. So Monday is the date of full moon, even though for most of us who keep more civil sleeping routines, the moon was closer to being full on Sunday evening. In order for the moon to be technically full, it must be opposite the sun in the sky. Whenever this moment occurs, the moon is considered full at all locations throughout the world. "Lunatics," skywatching in California on Monday morning will be able to witness the exact moment of full moon at 3:55 a.m., PDT. Catch Saturn just above a waning gibbous moon around midnight on Thursday.

052    AUGUST 24, 1997:   Planets Don't Twinkle

If you saw Saturn near the moon late last week, you may have noticed an even brighter "star" in the south. That was the planet Jupiter. Jupiter is visible low in the southeast right after dark. If you compare Jupiter to any of the other stars in the sky, you should notice two important things. Its brightness is impressive, and Jupiter is shining with a steadier light. These two observations are the sure give-away for any of the traditional planets seen by the ancients. Planets shine with a steady light because, unlike stars, they can be magnified with telescopes into disks. No matter what the power, stars will always appear as pinpoints of light. The motion of the ocean of air that we live under is much more effective in causing point sources to twinkle than light coming from magnifiable disks. Hence, planets shine with an unwavering light, while stars twinkle. More about this in two weeks.

053    AUGUST 31, 1997:   Moon, Venus, and Mars Pair Off

Happy First Birthday StarWatch! Readers suggestions regarding this weekly sky bulletin are always appreciated and can be left as a phone message at 610-820-2204 or e-mailed to gabecker@itw.com. The moon is new on Monday evening, but by Wednesday, it begins to enter the scene as a thin crescent, low in the west. Venus is far to the moon’s left, but the moon quickly catches up to the Goddess of Beauty, and the two make a striking photographic pair in the darkening evening sky by Friday. On Sunday, the moon and Mars are now pairing off in an even darker sky. Remember how Mars and Comet Hale-Bopp dominated the heavens in the spring? Since then, Earth and Mars have moved much farther apart. This has caused the Red Planet to appear a little over 8 times fainter than it was in late March.