Moon to Muscle in on Perseid Meteor Shower

For Northern Hemisphere observers, August is usually regarded as "meteor month" with one of the best displays of the year reaching its peak near midmonth.  That display is, of course, the annual Perseid Meteor Shower beloved by everyone from meteor enthusiasts to summer campers. 

But skywatchers beware: you will be facing a major obstacle in your attempt to observe this year's Perseid performance, namely, the Moon.

Unfortunately, as luck would have it, 2006 will see the Moon will turn full on August 9 and will be at a rather bright waning gibbous phase a few nights later, seriously hampering observation of the peak of the Perseids, predicted to occur for the night of August 12-13. The Moon will be hovering below and to the left of the Great Square of Pegasus that night and not all that far from the constellation Perseus, from where the meteors will appear to emanate (hence the name "Perseid"). 

Bright moonlight will flood the sky through most of that key night and will certainly play havoc with any serious attempts to observe these meteors. 

In the 2006 Astronomical Calendar, meteor expert, Alastair McBeath concurs: "Sadly, the Moon intervenes to spoil the Perseid's best, even if we get clear skies."

The Perseids are already around, having been active only in a very weak and scattered form since around July 17.  But a noticeable upswing in Perseid activity is expected to begin during the second week of August, leading up to their peak night.  They are typically fast, bright and occasionally leave persistent trains.  And every once in a while, a Perseid fireball will blaze forth, bright enough to be quite spectacular and more than capable to attract attention even in bright moonlight.

Even more unfortunate, because the Moon is full on August 9, it means that it will always be above the horizon the predawn morning hours (when Perseid viewing is always at its best) in the few days before the peak.  So even the gradual increase in the shower will be spoiled by moonlight.  The Moon arrives at last quarter on August 15 and thereafter its light becomes much less objectionable, but by that time the peak of the display has long since passed, leaving only a few lingering Perseid stragglers in its wake.

In the absence of moonlight a single observer might see up to 100 meteors per hour on the peak night, a number that sadly can not be hoped to be approached in 2006.  But in 2007, it will be a much different story, as the peak night will coincide with a New Moon, meaning that skies will be dark and meteors plentiful. 

As they used to say in Brooklyn, when the Dodgers used to play at old Ebbetts Field: "Just wait till next year!"

Basic Sky Guides

• Full Moon Fever
• Astrophotography 101
• Sky Calendar & Moon Phases
• 10 Steps to Rewarding Stargazing
• Understanding the Ecliptic and the Zodiac
• False Dawn: All about the Zodiacal Light
• Reading Weather in the Sun, Moon and Stars
• How and Why the Night Sky Changes with the Seasons
• Night Sky Main Page: More Skywatching News & Features

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.