The peak of this year’s Perseid meteor shower will occur during the early morning hours (i.e., after midnight) on Aug. 12.
Unfortunately, this year’s shower will be marred by the brightness of a third-quarter moon, which will rise at 11:45 p.m. and erase the dimmer meteors.
My usual advice is to try to spot meteors after local midnight and to give up only when morning twilight on Aug. 12 spoils the view.
But not this year. Because of the rising moon, you might want to be at your observing sight as darkness settles in during the evening of Aug. 11 and stick it out until the bitter end. You may see as many meteors before midnight as after.
Also, if the sky looks like it’s going to be cloudy during the peak night, consider going out the night before and the night after if the weather forecast looks good.
The shower has a second, weaker peak during the nighttime hours of Aug. 12/13, but the moon rises even earlier that night. You’ll see far fewer meteors, but a few meteors are better than no meteors at all.
Why all this rigmarole? Perhaps a bit of explanation is in order.
Meteors happen when hunks of space debris slam into Earth’s atmosphere. They burn up from friction with the air and leave the familiar streaks of light.
When you see the streak of light, you are not seeing the actual hunk of rock burning up. The heat from friction “excites” (“ionizes” is the technical term) the molecules of air around the meteoroid. You are really seeing the glowing, excited air around the meteoroid.
Those streaks are technically named “meteors” but are more commonly called “shootin’ stars,” by cracky. Indeed, if a star, which is a hydrogen bomb much larger than planet Earth, actually shot out of the sky, the view would be incredibly spectacular before Earth was fried like a mosquito in a giant bug zapper.
In a sense, every clear, moonless night is a great night to go meteor observing. Since as many as a trillion particles enter Earth’s atmosphere every day, you’ll see about five meteors every hour if you observe on a moonless night from a dark, rural site.
Meteor showers happen when the Earth passes through a trail of space debris left by a passing comet. The particles, most of which are no bigger than a grain of sand, smack into Earth’s atmosphere at blazing speeds of up to 100,000 miles per hour.
Most of that speed is not achieved by the motion of the meteoroid in space. Earth is zipping along in its orbit at 67,000 miles per hour. Technically speaking, Earth smacks into the meteor and not the other way around.
The meteors appear to radiate from the direction of the constellation Perseus (Perse-ids, get it?). If you trace the streaks back to their apparent point of origin, they all seem to originate in Perseus because that’s the direction that Earth is moving in its orbit around the sun.
However, there’s no percentage in looking directly at the constellation. Meteors will appear all over the sky.
The host comet for the Perseids is Swift-Tuttle, which in 1992 returned to our neck of the solar system after an absence of 212 years. As it passed near Earth’s orbit, it left a brand-new trail of meteor fodder, a small part of which will come crashing into our atmosphere on August 11 and 12.
That happy cosmic coincidence makes the Perseids one of the most spectacular showers of the year during any given year. It may not be the best one this year, though. December’s Geminid meteor shower is a bit better, but December’s frigid temperatures and cloudiness usually make even the most diehard meteor observer reluctant to go outside.
In the meantime, the Perseids will provide a nice tune-up for the Geminids, and it’s a bit warmer in August than December, by cracky.
Although it is not true this year, generally speaking, the best time to observe meteors on any given night is after local midnight. Local midnight just happens to be around 1:30 a.m. Two factors are at work to move the real midnight to 1.5 hours later by the clock.
First, we are in the midst of Daylight Saving Time. That accounts for one hour of the extra clock time. Second, we are about halfway into our time zone. That accounts for the additional half hour.
Why after local midnight, you grumble? Earth rotates on its axis as it orbits the sun. Before local midnight, our spot on the planet is pointed away from the direction of Earth’s orbit.
This situation is much like being a passenger facing toward the rear windshield of a car. A few bugs might hit the rear windshield, but they’ll have to be flying really, really fast.
After midnight, you are facing forward into the direction of Earth’s orbit. The bugs don’t have to play catch-up with Earth’s velocity, and you’ll see a lot more of them splattering against Earth’s front windshield.
As a result, more meteors enter the atmosphere after midnight, and the display increases in intensity until just before morning twilight as Earth turns into the direction of its orbit. During that magical hour, you might see as many as one streak of light per minute, even with the moon in the sky.
Don’t give up until morning twilight brightens the sky.
A few practical hints:
1. Do your meteor observing under the darkest rural skies you can find. You won’t see many meteors if you’re anywhere near a city because the glow from streetlights blots them out (Now don’t you wish you had joined your local astronomy club so you could have access to their dark-sky observing sites?).
2. Get comfortable, but not too comfortable. Lying on a blanket with a cup of hot chocolate late at night isn’t conducive to alertness. Try a lawn chair set at about a 45-degree angle. The metal rods jutting into your body will help to keep you awake.
3. Also, an occasional slug of coffee (preferably cold and vile tasting) works wonders if you don’t overdo it. There’s nothing quite like missing the best display of meteors because you’re looking around for a bush.
I find that eating instant coffee right out of the jar helps keep me awake and reduces the number of bush forays. Most people don’t like coffee as much as I do, however.
4. Take along a 55-gallon drum of bug repellent. The mosquitoes will be sending telegrams to all their relatives about the “stargazer buffet” they’ve just found.
If all those nasty chemicals in mosquito repellent make you queasy, try one of the non-toxic, “natural” alternatives. They don’t actually work, but they are so redolent of pine that the mosquitoes might think you’re a tree (and they are safe for kids, dogs, and adults who want to give birth to unmutated children).
5. Get some sleep before you drive back. As my wife likes to say, “Tom, there’s a bridge abutment out there with your name on it.” I’ll admit that it’s just a tad awkward to show up at the Motel 3 in Middleofnowhere, Ohio at 6 a.m. and tell the clerk that you want to rent a room for “just a couple of hours.” However, your life and the lives of those you love depend on it.
6. You don’t need to look in the direction of the constellation Perseus. Meteors will appear all over the sky. Look straight up or in the direction farthest away from the
streetlight glow of local municipalities and, this year, the rising moon.
7. Forget about binoculars and telescopes for once. The binoculars you were born with (your eyes) give the widest field of view. Use your peripheral vision to see as much sky as possible. You’ll catch quite a few meteors out of the corners of your eyes.
Or maybe not. Meteor showers are inherently unpredictable. The morning hours of Aug.12 might be painfully devoid of meteors, or they could fall like snowflakes on an early winter’s evening. The only way to find out is to go and look.
If the meteors are sparse this year, remember that Earth passes through this same neck of the solar system at this time every year.
In the idle moments between meteors, consider this strange, perhaps coincidental, connection between the old Greek story of Perseus’s birth and the meteor shower emanating from the constellation that represents him in the sky.
Perseus was half human and half god because he was the product of an illicit liaison between Zeus (Jupiter to the Romans) and Danae, the beautiful and innocent daughter of King Acrisius.
To prevent Danae from marrying, the king locked her in a tower, vowing that the all-too-human eyes of potential suitors would never again gaze upon her.
The unlucky king didn’t figure on immortal eyes, however. Zeus, king of all the gods, easily saw through the tower walls.
To circumvent the king’s security measures, Zeus turned himself into a shower of gold coins and rained himself down on Danae’s lap through a skylight. Nine months later, Perseus was born.
Every year around the middle of August, we see that mythic shower of gold to this very day.
Tom Burns is the former director of the Perkins Observatory in Delaware.