August's Perseid meteor shower may be one of the most dependable sky shows of the year, but the viewing conditions can be as inconstant as the moon — literally. Fortunately, the moon's glare won't be a factor this year, which means the show should be about as good as it gets over the next few days.
The prime viewing hours should come Sunday night. Or is that Monday night? This year, some say the peak is Aug. 11-12, while others say Aug. 12-13. What's a stargazer to do??
"I can understand the confusion you mention, as the predicted peak is around 3 p.m. EDT on the 12th," Bill Cooke, head of NASA's Meteoroid Environment Office at Marshall Space Flight Center, told NBC News in an email. "Since it occurs mid-afternoon, arguments can be made for the night of the 11th-12th, or the night of the 12th-13th. I am leaning toward the night of 11th, as there are usually more meteors seen leading up to the peak than after. ... If it were me, I'd go out both nights."
Cooke plans to get the party started even earlier, on the night of Saturday, Aug. 10, when he and his friends at Marshall will conduct a live online chat. Cooke and his officemates, Danielle Moser and Rhiannon Blaauw, will take your questions from 11 p.m. to 3 a.m. ET. The chat page will also feature a live video feed from all-sky cameras that have been set up to catch for meteor flashes.
At its peak, observers could see an average of two flashes per minute, depending on viewing conditions. This is expected to be a better-than-average year because the moon will be just a few days past its new phase. The lunar crescent will be setting early in the evening, leaving glare-free skies during the midnight-to-dawn period that's most favorable for meteor sightings.
The Perseids flare up when Earth passes through the trail of cosmic debris left behind by Comet Swift-Tuttle, which orbits the sun every 133 years. As our planet turns into the trail, bits of grit spark ionized trails dozens of miles up in the atmosphere. If the bits are big enough, a majestic fireball can flare up. Some people even swear they can hear the fizz of a bright meteor passing over.
There's another way to "hear" meteors: SpaceWeather Radio monitors the radio pings from meteors and satellites passing over the U.S. Air Force Space Surveillance Radar in Texas. When a meteor zooms by, you can hear a freaky whistle amid the static. This archived feature from SpaceWeather.com explains how it works.
Make the most of meteors
Online video and audio clips of meteors are all well and good, especially if the weather's cloudy, but the next few days should be about getting outside and communing with the cosmos. Here are a few tips to make the most of the meteors:
- Pick a viewing spot far away from city lights, with clear and unobstructed skies. 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.
- 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. Perseid meteors will appear to emanate from a point in the constellation Perseus, known as the radiant. But 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."
- 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 want to share your meteor sightings via Twitter — and find out where sightings are sizzling — the MeteorWatch website is the place for you.
- Want to take a picture? "Set up your camera just off center of the radiant where the Perseids originate from," photographer Jeff Berkes says. "Bracket your exposures. You want to let a lot of light in your lens, so use an ISO between 800 and 1600 and shutter speeds between 15 and 30 seconds. Be patient and keep shooting, you will certainly get one!"
If you do get a great picture, please share it with us! Alert us to your meteoric masterpieces by adding the hashtag #Perseid or #NBCNewsPics to your tweets or Instagram posts, or upload your pictures directly by clicking the box below. We'll pass along a selection of your stunners. SpaceWeather.com and Space.com are planning Perseid galleries as well.
More about meteors:
- The scientific story behind the meteor show
- Flash interactive: Inside a meteor shower
- NBC News archive on meteors
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding +Alan Boyle to your Google+ circles. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.