We're nearing mid-August and there are three reliable activities in mid-August: Back-to-school sales, burning hot weather, and one of the best meteor showers of the year. You already know about the sales, and we can't avoid the weather, so let me fill you in on the upcoming Perseid (PURSE-ee-id) meteor shower. Meteors are one of the most entertaining and exciting objects in the sky (but not for long!). The action is best on the nights of August 12 and 13, so read on and be ready for the show if we have clear skies.
You've probably seen meteors flash across the sky in night. Maybe you've made a wish on one. Any night you might see three or four if you find a clear, dark sky and keep your eyes looking up. Those are random space bits -- bits of space rock from who-knows-where or tiny pieces of orbiting rockets. But several times each year, Earth's path crosses an area where comets loop around the Sun in their orbit. As comets orbit the Sun, they lose bits of dirt, ice, and stone and this debris drifts around along the orbit. If you've driven behind an open-bed truck full of sand, you can get a sense of the trailing stuff. As we pass through the orbital path of a comet, that comet junk hits our atmosphere and it burns up. That gives us a streaking light show for a moment. The best showers give the most meteors per hour. Our August shower can deliver more than 100 meteors per hour on the peak day, at the peak time and with clear, dark skies.
The shower is named "The Perseids" because the path of the meteors in the sky traces back to a point (the "radiant") near the constellation Perseus. That's not an easily recognizable constellation, but the radiant is also close to the easily recognized Cassiopeia -- the giant "W" in the sky. You can see the most meteors if you watch the area near the radiant. But if you want to see the BEST meteors, look above or to the side of the radiant. Those areas of the sky won't have the most meteors, but the long streaks are much more interesting than the short, stubby meteors near the radiant.
Watching meteors is the astronomy equivalent of fishing: It takes patience and you might need to make trade-offs that fit your circumstances. For example, the best time to see a lot of meteors is in the final stretch of darkness before the dawn twilight. 3-4 am might not seem like a time to have fun staring at the sky to see some meteors. But you can see the Perseids and other meteor showers in the late evening and later the vicinity of midnight -- you just won't see as many meteors as the die-hard pre-dawn folks. The 2015 Perseids promise to be a good show because the Moon won't throw a lot glare around the sky. When the Moon is bright (as in 2014), we don't see many of the dim meteors. The Moon will be very dim this year so take advantage of the good arrangement.
Meteor watching doesn't require much equipment. For a meteor shower in August, you'll need some bug repellent. Most serious meteor watchers prefer a reclining lawn chair so to prevent neck stiffness. Telescopes and binoculars aren't much help because meteors move too fast. Just find a nice part of the sky to watch, stretch out, and enjoy. Avoid lights as much as possible. Kids can have fun with some late-evening meteor watching. They just need to watch the sky and shout when they see a streak of light.
The constellation Cassiopeia will be low in the northeast about 8:30 pm. Perseus will follow behind Cassiopeia as they both climb higher in the northeast. The radiant is between them. You can focus your attention there for the most meteors or look aside for the more exciting meteors.
If you miss the peak nights of August 12 and 13, you can still catch a few rogue Perseids for another 8 or 9 nights. After that, our next good 2015 meteor shower is in December: Good bye, bug repellent; Hello, heavy coat and gloves.
For more ideas on meteor watching and links to other meteor websites, check out the Salem Skies blog at http://salemskies.blogspot.com/2013/11/meteors.html .
Here are some other links for the 2015 Perseids:
http://patch.com/california/southpasadena/2015-perseid-meteor-shower-peak-when-where-how-view-across-us
https://in-the-sky.org/news.php?id=20150813_11_100
http://www.amsmeteors.org/2015/08/perseids-2015-the-amateur-guide/
http://www.skyandtelescope.com/astronomy-news/observing-news/plan-for-the-perseids/
The 2015 Perseids were a treat in Dent County. The weather was clear and comfortable. The Moon was not an obstacle at all. On the peak night of the 12th, I counted 101 Perseids. I averaged about 30 meteors per hour, not bad. A group of 3 or more would probably see 100-120 in that time. More meteors to come in 2015. Stay tuned.
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