Moonshadow, moonshadowWritten by Don Hendershot
I was all set to write about the annual summer fireworks displayed every August on that really big screen above our heads, brought to us free of charge by the comet Swift-Tuttle and sponsored by your universe.
Then I looked at a lunar table — arrrggghh, not much dampens a meteor shower like light. And a big ole full moon is going to be with us from before sunset on August 13 — supposedly the peak of this year’s Perseid meteor shower — till after sunrise August 14. And to make matters worse, some Internet sleuthing discerned that the best time to peek at Perseids this year would likely come just before dawn, today, August 10, before this week’s edition of the Smoky Mountain News hits the streets.
But, wait, there’s still hope. There will be a decent viewing window Thursday morning, since the full moon will set around 4:30 a.m. but sunrise isn’t until around 6:45 a.m.
Friday morning will offer the same type of scenario but with only about an hour of decent viewing time.
But remember, as we approach the peak of the Perseids, there could be 20 or more meteors or “falling stars” in a single hour. Also remember that August 13th is the peak, the Perseids will continue, though in smaller numbers, through the end of the month and that pesky ole moon will be down to a sliver by August 21.
Between midnight and dawn are the best times to search for Perseids, even on moonless nights as they radiate from the constellation Perseus the Hero, which rises into the northeastern sky around 11 p.m. in August.
Ins and outs of viewing a meteor shower
Think of the earth as your sleek sports coupe and the night sky is your windshield. Between midnight and dawn you’re screaming down the Autobahn pointed at Perseus, and the Perseids are like love bugs on a Florida interstate headed straight for your windshield. When these tiny bugs — usually pea-sized bits of cosmic comet debris — strike your windshield (the Earth’s atmosphere) at thousands of miles per hour the friction ignites them like flares. The friction is so great it actually breaks the molecules, both of the meteoroid and the molecules of the atmosphere. These glowing, ionized particles then recombine, releasing light energy, behind the meteoroid, which is traveling at 40 miles per second so the tail can stretch behind for miles.
Now some astronomers like to take their coupe for a cruise earlier in the evening. At this time, the radiant is lower on the horizon and instead of striking your windshield head on, the cosmic bugs will slide by, past your side windows.
Astronomers call these glancing meteors “Earthgrazers” and they can produce exceptionally long and colorful tails.
And if you’re determined to watch for Perseids during their peak on August 13th, in the glow of the full Green Corn Moon, the EarthSky website offers this advice:
“Sprawl out in a moon shadow. The best viewing on any date is from about 2 a.m. until dawn. As seen from mid-northern latitudes, the moon will be shining low in the south to southwest sky on the peak nights. That means the moon will be casting looooong shadows. Find a moon shadow somewhere that still provides a wide expanse of sky. A plateau area with high-standing mountains to the south and southwest would work just fine. If you can’t do that, find a hedgerow of trees bordering a great big hay field somewhere (though obtain permission, if it’s private land). Or simply sit in the shadow of a barn. Ensconced within a moon shadow and far from the glow of city lights, the night all of a sudden darkens while the meteors brighten.”