Perseid meteor shower 2019


By Tom Burns - Stargazing



This year, the annual Perseid meteor shower peaks on Monday night and Tuesday morning, i.e., the period of nighttime starting after sunset on Aug. 12 and ending during morning twilight on Aug. 13.

That’s the good news. The bad news is that a nearly full moon will blind you to all but the brightest meteors, which are sometimes called fireballs or more properly, bolides.

The good news is that you may see as many as 10-15 of those meteors per hour, especially if you wait until the very best time to observe meteors.

The bad news is that the best time is between 3-4 a.m. during the wee hours of Aug. 13.

In other words, even if you’re a meteor-shower aficionado, this year is not your year.

Just why this year is a terrible time to go Perseid observing requires a bit of explanation.

A meteor is a streak of light flashing briefly across the sky. The streak is caused by a tiny piece of space junk, material left over from the formation of the sun and planets. Most of these particles, called meteoroids, are no larger than a grain of sand. When they hit the Earth’s atmosphere, they are traveling about 37 miles per second, or 135,000 miles per hour. Virtually none of these specks has any chance of reaching the ground. Friction with air causes them to burn up, high in the atmosphere. We see only their glowing vapor trails. You don’t need a meteor-shower night to see meteors. About a trillion meteoroids collide with our atmosphere every day. On average, you’ll see about five meteors per hour if you go away from city lights on any clear, moonless night. Meteor shower nights are special because the Earth happens to be traveling through a cloud of debris left by a passing comet. The particles that make up such comet trails are mostly dust-size. The Perseids get their name because they seem to radiate from a point in the constellation Perseus, which happens to be the direction the Earth is moving through the dust cloud.

That doesn’t necessarily mean that you should look in that direction. The meteors will appear all over the sky. You should look in whatever direction is most free of the glow of city lights. For example, if you’re observing north of Columbus, look north away from Columbus.

Since most of your observing will happen with a bright moon in the sky, I’d also strongly suggest that you look at the sky with the moon at your back, in other words, in the opposite direction to the moon. Stay away from outdoor lights. They ruin your precious night vision, and you’ll see even fewer meteors. Normally, I’d suggest traveling to a dark, rural sky to see the shower. This year, the moon will act like a big streetlight in the sky, so it doesn’t matter so much where you observe.

At the least try to find an observing location with a clean horizon as free of trees and buildings as you can muster.

Lie back in a lounge chair so that you’re looking only at the sky. There’s no point in wasting your peripheral vision on trees or the horizon. The best time to observe is after midnight Monday morning.

Stick around until morning twilight spoils the view. The moon sets at 2:52 am that morning, so you’ll have a brief respite from its brightness before morning twilight erases the display.

But there is an even more important reason to stick around until morning twilight.

As Earth rotates on its axis, you will eventually turn into the direction of Earth’s motion through space after local midnight. Because of Daylight Saving Time and our location in the time zone, local midnight actually occurs at 1:35 a.m., by the way.

As Earth spins around, you will increasingly be facing in the same direction as Earth is moving through the cloud of debris. Before midnight, you are facing away from the direction of motion, so you will see far fewer meteors.

In my youth, I was somewhat confused by the “after-midnight” concept, but many years of observing meteors have proven it true.

The first time I observed the Perseids from a truly dark location, I had the honor of having it explained to me by legendary amateur astronomer Biff Smooter.

“Yer drivin’ yer car,” he whispered through the darkness. “Are ya’ gonna see more bugs hit the front windshield or the back one?”

Thanks, Biff. Got it.

The frequency of meteors will also depend on your observing location. From in or even near Delaware or Columbus, you might not see any meteors at all.

Most years, it’s worth the trip to rural Ohio.

Last year was moonless, and I took the opportunity to observe under the dark sky of the John Glenn Astronomy Park in southern Ohio. I saw 112 meteors during the last hour before morning twilight. So here’s hoping for better luck next year. Here’s some basic advice if you decide to observe next year.

Don’t expect the meteors to be evenly spread out. You might see one every second for a while and then wait 10 minutes or longer for the next one. The best way to observe meteors is to use the optical devices you were born with. Telescopes and binoculars are a hindrance because they limit your field of view. Most meteors look like faint streaks of light and last no longer than the blink of an eye. If you’re lucky, a few larger meteoroids might be in the swarm. If so, the streak might last a few seconds, and it will flash brilliantly and change color as its various elements burn.

Take along a gallon or so of bug repellant. There’s nothing that spoils a good meteor-shower display more than if you become the main dish in a delightful mosquito buffet.

Most importantly, be patient. Over the years, many newbie meteor observers have complained to me that they saw very few meteors. It usually turns out that they showed up in the early evening, left after an hour or two, and missed the best part of the pre-dawn show. If you begin to lose heart, consider this. Much of the debris that forms meteors

has remained unchanged, frozen in comets or floating in the interplanetary void since the formation of the solar system 4.5 billion years ago. For an instant, the smallest fraction of time in the immensity of cosmic history, those tiny specks flare to brief brilliance in a spectacular swan song as they are destroyed.

Now, isn’t that worth losing a few hours sleep?

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By Tom Burns

Stargazing

Tom Burns is the former director of the Perkins Observatory in Delaware.

Tom Burns is the former director of the Perkins Observatory in Delaware.