Animation Credit: NASA MSFC
Your goal: to observe a meteor shower. You want to see as many meteors as possible. You want to see the sky rain meteors like hailstones at an apocalyptic rate. You want exploding fireballs, peals of meteoric thunder, celestial mayhem. And it could happen, too, because you read an article online about this meteor shower.
And so here you are. You have your sleeping bag, the requisite thermos of coffee. At any moment, the sky should open up and rain down meteors.
The minutes tick by. Half an hour. An hour. Still you wait. Nothing happens. It’s cold. You’re sleepy. You should be in bed. You don’t even like coffee. Finally, you toss aside the sleeping bag and trudge back inside the house grumbling. Again, you read the date of the peak: “before dawn on April 22.” Then it hits you. That was yesterday morning. Which brings us to the first rule of meteor shower observing.
1. Be sure you know which day the shower will peak.
The “peak” is just what it implies. It’s a point in time when Earth encounters the greatest number of particles from a particular meteor stream. You can find this date nowadays easily on the Internet. Try EarthSky’s meteor guide for 2013.
But there’s a catch.
That is, the peak of the shower comes at the same time for all of us on Earth. Meanwhile, our clocks are saying different times. So …
2. Find out the time of the shower’s peak in your time zone.
The time of the peak may be given in Universal Time. That’s the time in London. During the winter months, it’s 6 hours ahead of central time in the U.S. To learn how to translate Universal Time to your time zone, try this article.
Suppose the peak is at 8 Universal Time on the 12th. That doesn’t mean you should go outside on the night of the 12th to watch the shower – unless you live in Asia. For central U.S. observers, 8 Universal Time translates to 2 a.m. on the 12th. So you’d want to be outside on the morning of the 12th, not the evening? See?
3. Watch on the nights around the peak, too. If you miss a shower’s peak, or if it occurs during daylight in your part of the world, you won’t see as many meteors. But don’t let that discourage you! Predictions of the peak are not always right on the money. And it’s possible to see very nice meteor displays hours before or after the true peak.
For example, who can forget the notorious 1998 Leonid meteor shower? The predicted peak favored observers in Europe, and yet those of us in the states were nevertheless treated to wonderful displays of Leonids on the nights before and after the predicted peak. Just remember, meteor showers are part of nature. They often defy prediction.
4. Don’t take the notion of a radiant point too seriously. A meteor shower’s radiant point is that point in the sky from which all the meteor showers will appear to radiate. Some people seem to think they have to be able to identify the radiant point in order to be able to watch the shower. Not so. You can see meteors shoot up from the horizon before a shower’s radiant has even risen into the sky.
The fact is, in any annual shower, you will see meteors in all parts of the sky. But it’s true that the meteors’ paths – if traced backwards across the sky – will point back toward the region of the radiant. If a meteor’s path does not point back toward the radiant point, then you’ve seen a sporadic meteor, not a true member of the shower.
5. Find out the shower’s rate, or number of meteors per hour. Here we touch on a topic that often leads to some bad feelings, especially among novice meteor watchers. Tables of meteor showers almost always list what is known as the “zenithal hourly rate” for each shower. The ZHR is defined as the number of meteors an observer may see per hour in a very dark, clear sky with the radiant overhead when the shower is at its peak. In other words, the ZHR represents the number of meteors you might see per hour given prime observing conditions during the shower’s maximum.
Now let’s apply this term to the real world. April’s Lyrid meteor shower has a ZHR of 10-20 meteors per hour. That doesn’t mean, though, that you will see 10-20 meteors per hour from your backyard, even if you’re located hundreds of miles from the nearest city. If the peak occurs when it’s still daylight at your location, if most of the meteors are predominantly faint, if a bright moon is out, or if you’re located in a light-polluted area, the total number of meteors you see will be considerably reduced. However, some meteor shower – such as April’s Lyrid shower – are known to have bursts of activity. The Lyrids might, in some hours, burst forth with 100 meteors per hour. Which hours will those be? No one knows! You just have to watch and wait.
And that brings us to one of the most important factors of all for meteor-watchers.
6. You must be aware of the phase of the moon. If the moon is at a quarter phase or greater, you’re going to miss meteors, even if your skies are otherwise dark. It’s okay if the moon sets before the radiant rises, because the Earth blocks the moon’s light from the sky. But nothing dampens the display of a meteor shower more effectively than the presence of a bright moon.
Now you’re almost ready. Just a few final tips.
7. Dress warmly. The nights can be cool or cold, even during the spring and summer months.
8. Bring along that thermos of hot coffee or tea. It’ll be your friend at 3 a.m.
9. Bring a blanket or lawn chair for reclining comfortably while looking up at the sky.
10. Relax and enjoy the night sky. Not every meteor shower is a winner. Sometimes, you may come away from a shower seeing only one meteor. But consider this. If that one meteor is a bright one that takes a slow path across a starry night sky … it’ll be worth it.
To be really successful at observing any meteor shower, you need to get into a kind of Zen state, waiting and expecting the meteors to come to you if you place yourself in the position to see them. Or forget the Zen state, and let yourself be guided by this old meteor watcher’s motto: you might see a lot or you might not see many, but if you stay in the house, you won’t see any.
By the way, if you’re interested in learning more about meteor showers, or want to contribute meteor counts and brightness estimations, contact the following organizations: The American Meteor Society and the International Meteor Organization. Both provided the latest predictions as well as information to guide you in serious meteor observing.