A look at the Perseid fireball count for August 13th UTC confirms that the maximum for the 2012 Perseid meteor shower has come and gone. NASA's All Sky Fireball Network (fireballs.ndc.nasa.gov) determined that 41 of the fireballs it recorded during the dark hours of August 13th UTC were from the Perseid meteor shower. This is in great contrast to the 148 recorded August 12th and the 19 recorded August 11th.
The Network currently uses eight video cameras to observe, with two in New Mexico and the rest spread over Alabama, Georgia and South Carolina. For these Network observations, a fireball is defined as any meteor with a brightness equal to Venus or brighter.
But even though the maximum is in the rear view mirror, there are still plenty of Perseids to see. The shower runs from July 23rd through August 20th. You are sure to see at least a few Perseids if you observe from a reasonably dark sky.
Perseids enter the atmosphere at about 59 kilometers/second (37 miles/second) and are yellow in color. The Perseid shower occurs each year when Earth passes through the debris trail of Periodic Comet 109P/Swift-Tuttle, also called Comet 1862 III, discovered on July 16, 1862 by American astronomer Lewis A. Swift and then independently discovered three days later by American astronomer Horace Parnell Tuttle. Perseid meteors appear to radiate from a point in the constellation of Perseus (Right Ascension 03hrs 04min, Declination +58°). For 2012, around the maximum, the zenithal hourly rate (from a single location) is expected to reach 60.
To learn more about meteors, comets, and asteroids, check out these URLs.
NASA's All Fireball Network (fireballs.ndc.nasa.gov), part of NASA's Meteoroid Environment Office, www.nasa.gov/offices/meo .
Asteroids, Comets, Meteorites (a NASA Asteroid Watch article): www.jpl.nasa.gov/asteroidwatch/asteroids-comets.cfm
NASA's Near-Earth Object (NEO) Program coordinates NASA-sponsored efforts to detect, track and characterize potentially hazardous asteroids and comets that could approach the Earth. To learn more, visit the home page of NASA's Near-Earth Object Program: neo.jpl.nasa.gov .