Brian Emfinger / RealClearWx.com
Brian Emfinger photographed this Perseid fireball in 2009. (More photos at RealClearWx.com.)
August's Perseid meteor shower ranks among the year's most popular sky shows, and provides a great opportunity to drink in a big gulp of night-sky goodness. So what if this year's meteor shower won't be as spectacular as it could be? There are still plenty of ways to maximize your enjoyment of this year's Perseid performance.
First, a reality check: In a normal year, observers could spot more than a meteor a minute under optimal viewing conditions during the peak of the Perseids, which usually comes on the night of Aug. 12-13. The conditions aren't optimal this year, however, because the moon is big and full during what are traditionally the best hours for meteor-watching, between midnight and dawn. All that glare makes it harder to see the fast, faint streaks of light in the night.
The best strategy is to find an observation point that's free of clouds and city lights, and also has an obstruction to the south that stands a chance of blocking the moon's disk — whether that's a barn, a tree or a mountain. Anything that reduces the glare will increase your chances of spotting meteors.
What to watch for
The Perseids' peak comes at the same time each year because that's when Earth travels through the path of gritty space debris left behind by Comet Swift-Tuttle, which crosses our planet's orbital path every 133 years. When those bits of grit pass through the upper reaches of our atmosphere at speeds of more than 125,000 mph, they light up trails of ionized air. Every once in a while, the more substantial bits flare up as fireballs.
The Perseids are so named because they appear to emanate from a spot in the constellation Perseus, known as the radiant. It's good to keep an eye on the radiant if you can, but in fact, meteors can flash anywhere in the night sky. For that reason, meteor-watching is best done with the naked eye rather than binoculars or telescopes.
Perseid meteors appear to emanate from a point in the constellation Perseus, as shown in this graphic depicting the northeastern sky at around midnight. Although the meteors can appear in any part of the sky, their tails can be traced back to that point.
However, you might want to bring along those things nevertheless, to look at other celestial sights such as Saturn (in western skies late Friday), Jupiter (in eastern skies early Saturday) and Mars (rising in the east just before dawn). Don't believe those hoax emails that claim Mars will be as big as the moon this month — but do take the opportunity to go planet-hunting if you can. The Heavens-Above website can show you where to look.
Another celestial object to watch for is the International Space Station, the brightest human-made object in the night sky. Many localities will have multiple opportunities to watch the space station on Friday and Saturday night. To check the schedule for your location, consult NASA's station tracking database.
Party all night ... online
Meteor-watching is best enjoyed as a group activity, and this year NASA will be presenting an all-night online party to keep track of the Perseids. Astronomer Bill Cooke and his colleagues from NASA's Marshall Space Flight Center in Alabama will be chatting away from 11 p.m. ET Friday to 5 a.m. Saturday. Click on over to this webpage to join the chat when it starts. There'll also be live video from all-sky cameras maintained by NASA.
Finally, here's a recap of last year's top-ten tips for maximizing even a mediocre meteor shower:
- Pick a viewing spot far away from city lights, where the skies are likely to be clear and wide-open. Higher elevations are usually better than lower elevations.
- For help in site selection, you can check out the Clear Sky Chart website, which provides weather conditions for skywatching ... and links to popular viewing locations on a state-by-state basis. Your local astronomy club can also point you in the right direction. Some events for amateur astronomers are timed to take advantage of the Perseids — for example, this year's star party in California's Mojave Desert.
- Bring a blanket or a chaise lounge to lie back on. Have layers of clothing available in case the air turns chilly at night. Bring snacks or drinks. Bring a flashlight so you can find your way through the dark.
- Bring a music player or radio if you need a diversion. But don't forget the earphones if you're going to be alongside other groups who may not appreciate your musical taste. Frankly, the best diversion is a deep philosophical conversation with your meteor-watching friends.
- Don't give up too quickly. Give your eyes plenty of time to get accustomed to the dark. Although the meteors appear to emanate from the radiant in Perseus, don't focus exclusively on that point. "The closer the meteor is to the radiant, the shorter the trail is," Cooke says. "I always tell people to look straight up, because that way, they'll catch plenty of meteors far enough from the radiant to see a trail."
- The later you can stay up, the better. Generally speaking, meteor shows don't get good until after midnight, when Earth is turning into the stream of meteor debris.
- To get a better sense of what to expect at which time, use NASA's Fluxtimator. When you click in the right coordinates for meteor shower, date, location and viewing conditions, the Java-based calculator charts what the estimated meteor flux will be at different times.
- If you're totally clouded out, you can try listening to the meteors. The video stream on NASA's Perseid Web page will be accompanied by a soundtrack of radio blips created by the meteor streaks. Cooke says it's also possible to hear the radio blips by tuning your FM radio to a station so distant that all you can hear is the hiss of a carrier wave. "When a meteor passes, you'll hear a blip kind of like a sonar blip," Cooke said. Here's a spooky audio file that gives you an idea what the radio echoes sound like. SpaceWeather Radio also lets you hear the meteors.
- If you want to share your meteor sightings with the world via Twitter — and find out where the sightings are sizzling — the MeteorWatch website is the place for you.
- Even if you miss the meteor shower completely, you can click through the gallery of greatest hits at SpaceWeather.com. And you can start making plans for the Leonid meteor shower (peaking Nov. 17-18), the Geminids (peaking Dec. 13-14) and next year's Perseids, when the moon conditions will be much, much better.
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