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The shower is visible from mid-July each year, but the bulk of its activity falls between August 8th and 14th with a peak on August 12th. During the peak, rates of hundred or more meteors per hour can be registered.
Meteor showers can be seen when Earth moves through a meteor stream. The stream in this case is called the Perseid cloud and it stretches along the orbit of the Comet Swift-Tuttle. The cloud is comprised of particles ejected by the comet as it passed by the Sun. Most of the dust in the cloud today is approximately thousand years old.
However, there is also a relatively young filament of dust in the stream that boiled off the comet during American Civil War, in 1862. The approximate rate of meteors originating from this filament is much higher than normal.
The Perseids are called so because the point they appear to be coming from, called the radiant, is in the constellation of Perseus. However, they can be spotted all around the sky. Because of the positioning of Swift-Tuttle's orbit, Perseids are mostly visible on northern hemisphere.
To experience the shower in its full, one should reach a point far outside any large cities, where stars are not dimmed by the cities' glow.
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