Meteor showers - What they are and how best to observe them.

By Bryan Simpson, CAS President

•Intro:

Meteor showers are one of the most talked about astronomy events among the general public. Part of the reason is that meteor showers happen year-round, and also because they are a fairly accessible astronomy event for all people, since they require no equipment to experience.

There are some things you should know however, in order to elevate your meteor shower viewing experience. This guide has been prepared to educate on meteor showers as well as give advice on the best way to observe them.

First off, it is important to always temper your expectations when it comes to meteor showers. While the general public has an elevated interest in them, most amateur astronomers rank them a little lower on their observing priority list. There are some reasons for that.

One reason is that meteor showers can be unpredictable, and have a reputation for being underwhelming. This is one reason CAS does not try to get people too excited about them, simply because they can have a tendency to be disappointing. Another reason is, to really get the full meteor experience it takes a little more effort than most people have time for.

We still want to help prepare you for observing them because they can be fun and are a wonderful experience for families and groups with little to no investment in equipment.

•What are meteor showers?

Meteor showers are produced by comets that have flown through the inner solar system, leaving behind a trail of debris which the Earth passes through every year roughly around the same time. For instance, the annual August Perseid meteor shower is the result of flying through the debris field of comet Swift-Tuttel. The Orionids, which happen every year in October, are associated with the debris left behind by Halley’s comet.

Meteors are tiny pieces of debris left behind by these various comets. Most of these particles are no bigger than grains of sand. But the Earth, which is moving through its orbit at a speed of 66,000 mph, slams into them as it moves through these debris fields. These particles burn up in our atmosphere as the Earth’s atmosphere comes into contact with them. Any meteors that are large enough to survive the atmosphere burn, and make it to the ground, are called meteorites. 

Each meteor shower happens very predictably as these debris fields sit in various parts of Earth’s orbit, making their appearance every year consistent with specific dates on our calendar. Perseids in August, Orionids in October etc….

The area in the sky where the meteors appear to originate from is called a radiant. Each meteor shower is named after the constellation in which its radiant sits. The Perseids are named because the meteors during this shower appear to originate from the constellation Perseus. Orionids from Orion, Leonids from Leo and so forth. 

Each meteor shower produces varied numbers of meteors which is also somewhat predictable. These meteors are measured by the number seen per hour. This is called a Zenith Hourly Rate, or ZHR. Zenith refers to the area of sky straight above an observers head. The ZHR represents how many meteors can be seen per hour when the radiant is near zenith. This represents the maximum number of meteors which can be seen on the night of a meteor shower’s peak.

Now that we have the basic knowledge of meteors, we can talk about how best to observe them.

•Observing Meteor Showers - Best Practices

Tip #1 Monitor meteor showers schedule on the calendar.

There are about 30 named meteor showers every year. Familiarizing yourself with them and their timing on the calendar, particularly the major showers, will help you make decisions on when to venture out for viewing. You’ll also want to focus on the showers that have higher ZHR production. The showers with lower ZHR numbers will be less worthy of your investment in time.

Tip #2 Cross reference moon phases with meteor showers

One of the biggest killers of the meteor viewing experience is the bright moon. It will vary from year to year when the bright moon will coincide with a meteor shower’s peak. You want to avoid meteor showers during the full moon, and probably about 7 days on either side of the full moon. Meteor showers during the new moon, and several days on either side of the new moon will create the best dark conditions for viewing. That means you want the moon at less than 30% illumination for viewing. A good moon tracking app can assist with your planning process.

Tip #3 Study light pollution maps in your area to find a good location

Just like the bright moon, light pollution can completely destroy the meteor viewing experience. Viewers in the city and even close suburbs will struggle to see all but a few of the brightest meteors of any given shower during their peak. Look for light pollution maps of your area that will assist in helping you find a nice dark spot to set up for viewing. The darker areas will show more meteors over time. One map amateur astronomers use is DarkSkyMap.com and another is ClearDarkSky.com

Tip #4 Monitor astronomy weather charts

This one is pretty common sense, but meteors are only going to be visible on clear nights. Use your favorite weather app to track nightly waether, or consider astronomy weather charts such as cleardarksky.com and astrospheric.com for the best weather predictions. One site/app that is used regularly by astronomers is astrospheric.com

Tip #5 Plan to stay up late

Most meteor showers are best seen late at night. That is after 11PM and before 4AM. This is mainly because the Earth turns facing many of the radiants late at night rather than right after sunset.

Tip #6 Get comfortable and be patient

Get a nice chair that leans back. Gravity chairs are great for meteor showers. You want to kick back, and face in the direction the radiant will be rising, which is typically east or northeast. Stare in a single direction rather than looking around the sky. Let the meteors come to your rather than hunting around for them with your eyes. Remember, these meteor rates are hourly. Even the best meteor showers will only produce a meteor or two every 1-2 minutes. Patience is key. Get a beverage and a blanket with some good music and enjoy the show.

Tip #7 Use binoculars rather than telescopes.

Meteor showers will appear over a fairly wide area in the sky which lends itself to naked-eye viewing rather than using a telescope. If you try to use a telescope, your chances of seeing meteors goes down significantly because telescopes have a narrower field of view. This limits how much sky you can see at any time. Binoculars typically have a wider field of view which still allows for finding meteors rather easily. The super low power binoculars, such as 2x magnification binocs have become popular among amateur astronomers for pulling dimmer stars into view while maintaining a wide field of view. These low power binoculars are excellent for viewing meteor showers.