There were three separate peaks in this year's Perseids per a spaceweather.com blurb, quoting IMO early analysis: "According to the International Meteor Organization, the shower peaked an extraordinary three times. The first peak, around 0800 UT on August 12th, was caused by Earth hitting a filament of dust shed by Perseid parent Comet Swift-Tuttle in 1610. The second peak, around 1800 UT on August 12th, was another cloud of dust from Comet Swift-Tuttle nudged toward Earth by the gravity of Saturn. The third peak, around 0600 UT on August 13th, is not fully understood." http://spaceweather.com/  Chart http://spaceweather.com/swpod2009/15aug09/triplepeak.jpg?PHPSESSID=bp70vq31n... IMO analysis http://www.imo.net/live/perseids2009/#peak IMO different scaled chart http://www.imo.net/live/perseids2009/#overview