The year's best astronomical show is about to begin. Meteor showers - or shooting stars, as they are better known - can be seen from the UK several times a year. But the most reliable display is the Perseids shower, which will start to become visible from Sunday night and peak around mid-August.

In the past there have been as many as 200 showers per hour, with the peak activity around midnight. The best viewing time for the meteor shower is after midnight. The meteor shower is caused by the Earth passing through a cloud of space dust - in this case the remnants of a comet.

The comet's nucleus ejects particles of unmelted ice, dust and rock which hurtle into the upper atmosphere. They then burn up to create streaks of visible light, commonly known as comet tails. These bright streaks can last for several seconds. Although the comet dust is small, at 45 miles a second, it is dangerous.

A dust particle from the Perseids shower is believed to have sent a European spacecraft out of control in 1993. The shower poses no danger to anyone on the ground, with meteors usually burning up at between 100 and 60 miles high.

Naked eye

The best time to view the display will be after midnight, when the night time sky faces the direction of the Earth's motion.

At its peak, in three weeks time, the Perseids shower should produce up to 70 shooting stars per hour. The highest number recorded is 200 showers per hour.

The naked eye is usually best for seeing meteors, which can often streak more than 45 degrees across the sky. The field of view of most binoculars and telescopes is simply too narrow.

Anyone who is thinking of staying up late to watch it is strongly advised by astronomers to wait until mid-August to avoid disappointment.