It's August and that means its time for the annual Perseid Meteor Shower, this year reaching its peak on the evening and through the morning of August 11-12. Meteors are visible just about any night of the year, but throughout the year there are periods of intense activity in the sky ("meteor showers") because the Earth travels through a point in its orbit where there is a higher amount of space dust, rocks and other particles that enter the atmosphere at tens of thousands of miles per hour and burn up, creating bright streaks across the sky.
The Perseid Meteor Shower is going to be harder to see in 2009 because of the bright Moon that rises at 10:40 pm in San Francisco. For the city dweller, however, the shower is not much worse because of the bright Moon, as our city lights obscure many meteors anyhow. So the best you can do is simply enjoy the shower the evening of August 11th from wherever you are in the city. Pick a darkened comfortable spot. Lay back on a blanket and point your feet to toward the north-east and look around the sky. As the evening wears on, the origination point ("radiant") of the meteor shower rises in the north-east. This area is near the constellations Perseus and Cassiopeia as shown in the illustration to the right.
This year there will be a possible jump in the number of meteors as the Earth passes through a denser-than-usual filament of dust from the remnants of comet Swift-Tuttle. That will happen around 1:00 am pacific time on the 12th, so if you are up late you might just see a more intense period of meteor activity. Throughout the entire evening, the Moon will remain the one bright light everyone cannot escape, so when it rises just point your gaze in another direction and keep your eyes on the sky. And stay warm!
If you want to see a good meteor shower this year that won't have moonlight in the way, look ahead to December 14th when the Geminids will peak at an even higher rate than the Perseids. However it will be considerably cooler and the weather is less predictable at that time.