Kick Back, Look Up, We’re In For a GREAT Perseid Meteor Shower

Every year in mid-August, Earth plows headlong into the debris left behind by Comet 109P/Swift-Tuttle. Slamming into our atmosphere at 130,000 mph, the crumbles flash to light as the Perseid meteor shower. One of the world’s most beloved cosmic spectacles, this year’s show promises to be a real crowd pleaser.

The author tries his best to enjoys this year's moon-drenched Perseids from the "astro recliner". Credit: Bob King
The author takes in last year’s moon-drenched Perseids from a recliner. Credit: Bob King

Not only will the Moon be absent, but the shower maximum happens around 3 a.m. CDT (8 UT) August 13 — early morning hours across North America when the Perseid radiant is highest. How many meteors will you see? Somewhere in the neighborhood of 50-100 meteors per hour. As always, the darker and less light polluted your observing site, the more zips and zaps you’ll see.

Find a place where there’s as few stray lights as possible, the better to allow your eyes to dark-adapt. Comfort is also key. Meteor showers are best enjoyed in a reclining position with as little neck craning as possible. Lie back on a folding lawn chair with your favorite pillow and bring a blanket to stay warm. August nights can bring chill and dew; a light coat and hat will make your that much more comfortable especially if you’re out for an hour or more.

The Perseids appear to radiate from spot below the W of Cassiopeia in the constellation Perseus, hence the name "Perseids". Source: Stellarium
The Perseids appear to radiate from spot below the W of Cassiopeia in the constellation Perseus, hence the shower’s name. This map shows the sky facing northeast around 12:30 a.m. local time August 13. Source: Stellarium

I’m always asked what’s the best direction to face. Shower meteors will show up in every corner of the sky, but can all be traced backwards to a point in Perseus called the radiant. That’s the direction from which they all appear to stream out of like bats flying out of a cave.

Another way to picture the radiant it is to imagine driving through a snowstorm at night. As you accelerate, you’ll notice that the flakes appear to radiate from a point directly in front of you, while the snow off to the sides streams away in long trails. If you’re driving at a moderate rate of speed, the snow flies past on nearly parallel paths that appear to focus in the distance the same way parallel railroad tracks converge.

At some personal peril, I grabbed a photo of snow in the headlights while driving home in a recent storm. Meteors in a meteor shower appear to radiate from a point in the distance in identical fashion. Photo: Bob King
Meteors in a meteor shower appear to radiate from a point in the distance in identical fashion to driving a car in a snowstorm. The motion of the car (Earth) creates the illusion of  meteors radiating from a point in the sky ahead of the observer. Credit: Bob King

Now replace your car with the moving Earth and comet debris for snow and you’ve got a radiant and a meteor shower. With two caveats. We’re traveling at 18 1/2 miles per second and our “windshield”, the atmosphere, is more porous. Snow bounces off a car windshield, but when a bit of cosmic debris strikes the atmosphere, it vaporizes in a flash. We often think friction causes the glow of meteors, but they’re heated more by ram pressure.

A bright fireball breaking to pieces near Yellow Springs, Ohio. Meteors are really tubes of ionized air energized by the passage of comet bits. Credit: John Chumack
A bright fireball breaking to pieces near Yellow Springs, Ohio. Meteors are really tubes of ionized air energized by the passage of comet bits. Credit: John Chumack

The incoming bit of ice or rock rapidly compresses and heats the air in front of it, which causes the particle to vaporize around 3,000°F (1,650°C). The meteor or bright streak we see is really a hollow “tube” of glowing or ionized air molecules created by the tiny rock as its energy of motion is transferred to the surrounding air molecules. Just as quickly, the molecules return to their rest state and release that energy as a spear of light we call a meteor.

Imagine. All it takes is something the size of a grain of sand to make us look up and yell “Wow!”

Speaking of size, most meteor shower particles range in size from a small pebble to beach sand and generally weigh less than 1-2 grams or about what a paperclip weighs. Larger chunks light up as fireballs that shine as bright as Venus or better. Because of their swiftness, Perseids are generally white and often leave chalk-like trails called trains in their wakes.

Comet 109P/Swift-Tuttle captured during its last pass by Earth on Nov. 1, 1992. A filament of dust deposited by the comet in 1862 may cause a temporary spike in activity on Aug. 12 around 18:39 UT. Credit: Gerald Rhemann
Comet 109P/Swift-Tuttle seen during its last pass by Earth on Nov. 1, 1992. A filament of dust deposited by the comet in 1862 may cause a temporary spike in activity around 18:39 UT on August 12. Credit: Gerald Rhemann

This year’s shower is special in another way. According to Sky and Telescope magazine, meteor stream modeler Jeremie Vaubaillon predicts a bump in the number of Perseids around 1:39 p.m. (18:39 UT) as Earth encounters a debris trail shed by the Comet Swift-Tuttle back in 1862. The time favors observers in Asia where the sky will be dark. It should be interesting to see if the prediction holds.

How To Watch

Already the shower’s active. Go out any night through about the 15th and you’ll see at least at least a handful of Perseids an hour. At nightfall on the peak night of August 12-13, you may see only 20-30 meteors an hour because the radiant is still low in the sky. But these early hours give us the opportunity to catch an earthgrazer — a long, very slow-moving meteor that skims the atmosphere at a shallow angle, crossing half the sky or more before finally fading out.

I’ve only seen one good earthgrazer in my earthly tenure, but I’ll never forget the sight. Ambling from low in the northeastern sky all the way past the southern meridian, it remained visible long enough to catch it in my telescope AND set up a camera and capture at least part of its trail!

A Perseid meteor streaks across the northeastern sky two Augusts ago. This year's shower will peak on the night of August 12-13 with up to 100 meteors per hour visible from a dark sky. Credit: Bob King
A Perseid meteor streaks across the northeastern sky two Augusts ago. Give the shower an hour’s worth of your time – you won’t be disappointed. Credit: Bob King

The later you stay up, the higher the radiant rises and the more meteors  you’ll see. Peak activity of 50-100 meteors per hour will occur between about 2-4 a.m. No need to stare at the radiant to see meteors. You can look directly up at the darkest part of the sky or face east or southeast and look halfway up if you like. You’re going to see meteors everywhere. Some will arrive as singles, others in short burst of 2, 3, 4 or more. I like to face southeast with the radiant off to one side. That way I can see a mix of short-trailed meteors from near the radiant and longer, graceful streaks further away just like the snow photo shows.

If there’s a lull in activity, don’t think it’s over. Meteor showers have strange rhythms of their own. Five minutes of nothing can be followed by multiple hits or even a fireball. Get into the feel of the shower as you sense spaceship Earth speeding through the comet’s dusty orbit. Embrace the chill of the August night under the starry vacuum.

Camelopardalid Meteor Shower Skimpy but Sweet

So how were the ‘Cams’ by you? Based on a few reports via e-mail and my own vigil of two and a half hours centered on the predicted maximum of  2 a.m. CDT (7 UT) Saturday morning the Camelopardalid meteor shower did not bring down the house. BUT it did produce some unusually slow meteors and (from my site) one exceptional fireball with a train that lasted more than 20 minutes. 

The 'Cam' left a long train across the Milky Way in the Summer Triangle. Credit: Bob King
This ‘Cam’ left a long train across the Milky Way inside the Summer Triangle. Credit: Bob King

I saw 10 meteors in all, most of them slow and colorful with orange and yellow predominating. My hopes were high when the shower started with a bang. At 12:34 CDT, a brilliant, very slow moving meteor flashed below Polaris at about magnitude -1.  A prominent train glowed many seconds after burnout and continued to show for more than 20 minutes in the camera and telescope. At low magnification in my 15-inch reflector (37-cm) the persistent glow looked like a brand new sausage-shaped diffuse nebula in Cassiopeia.

2.5 minute time exposure showing the persistent train left by a near-fireball brightness Camelopardalid meteor. The five bright stars form the familiar 'W' of Cassiopeia. Credit: Bob King
2.5 minute time exposure showing the persistent train left by a brilliant Camelopardalid meteor. The five bright stars to the right outline the familiar ‘W’ of Cassiopeia. Credit: Bob King

Trains form when a meteoroid’s hypersonic velocity through the upper atmosphere ionizes the air along the object’s path. When the atoms return to their rest states, they release that pent up energy  as a glowing streak of light that gradually fades. The train in the photos expands and changes shape depending on the vagaries of upper atmospheric winds. Absolutely fascinating to watch.

Pretty scene with the Big Dipper (upper left), a lake and a 'Cam' taken from Sudbury, Canada. Credit: Bill Longo
Lovely scene with the Big Dipper (upper left) and a ‘Cam’ taken from Sudbury, Canada. Credit: Bill Longo

Most activity occurred between 12:30 and 2 a.m. for my time zone in the U.S. Midwest. Surprisingly, the action dropped off around 2 and stayed that way until 3. I did get one ‘farewell Cam’ on that last look up before turning in for the night.

Malcolm Park of Toronto captured a bright Camelopardalid this morning.
Malcolm Park of Toronto captured a bright Camelopardalid this morning.

The team working with Gianluca Masi at the Virtual Telescope Project reported a number of bright meteors as well but no storm. We share several of their photos here. As more information comes in, please drop by for a more complete report. You can also check out Dirk Ross’s Latest Worldwide Meteor News for additional first hand reports.

The strange streak with a moving satellite (?) at its center than drifted from Leo to Auriga early this morning. The starlike object makes a narrower streak inside the cloud during the time exposure. Credit: Bob King
The strange streak with a moving satellite (?) at its center that drifted from Leo to Auriga early this morning. The starlike object made a narrower streak inside the cloud during the time exposure. Credit: Bob King

Before signing off for the moment, I’d like to ask your help in explaining a strange phenomenon I saw while out watching and photographing the shower. Around 1 a.m. I looked up and noticed a comet-like streak about 15-degrees long drifting across northern Leo. My first thought was meteor train – a giant one – but then I noticed that the center of the streak was brighter and contained a starlike object that moved in tandem with the wispy glow. I quickly took a couple pictures as the streak traveled north and expanded into a large, nebulous ray that persisted for about 1o minutes. There were no other clouds in the sky and the aurora was not active at the time.

Photo taken a couple minutes after the first one showing the expanding ray. The starlike object is the brighter trail within the ray near bottom. Credit: Bob King
Photo taken a couple minutes after the first one showing the expanding ray. The starlike object is the brighter trail within the ray near bottom. Credit: Bob King

Can anyone shed light on what it was??

UPDATE: According Mike McCants, satellite tracking software developer, the plume is fuel dump connected to the launch of a new Japanese mapping satellite. One never knows sometimes what the night has in store.