A meteor streaks past stars in the night sky at the Mont-Tendre near Montricher in the Jura, north of Geneva, late August 12, 2009. The Perseid meteor shower is sparked every August when the Earth passes through a stream of space debris left by Comet Swift-Tuttle. This picture was taken using a long exposure and a fisheye lens. ©Reuters

BEIJING, August 13 — The Perseid meteor shower, an annual event being tracked by astronomers for centuries, peaks this week.

In the Northern Hemisphere, the Perseids may be the best meteor watching event of the year, according to news reports on Thursday.

The phenomenon, which happens each summer as the Earth’s orbit takes it through debris scattered by the tail of Comet Swift-Tuttle, had been due to reach its peak early Thursday morning.

The meteors appear to come from a point called a “radiant” in the constellation of Perseus — therefore it is named Perseid.

No special equipment was needed to watch the shower, which occurs when Earth passes through a stream of dusty debris from the comet Swift-Tuttle.

Amateur astronomers worldwide showed their passions for the greatest concentration of Perseid meteors on Twitter, the networking website, where astronomers posted their sightings. One lucky England stargazer in Chelmsford, Essex, reported seeing 20 meteors in 40 minutes. 

On Xinhua Web site: http://news.xinhuanet.com/english/2009-08/13/content_11873734.htm