Starwatch: high-speed Leonids can be extremely bright and colourful

Dust grains forming meteor shower come from comet Tempel-Tuttle, which orbits sun every 33 years

One of the year's major meteor showers takes place this week. The Leonids may not typically produce the most meteors but they can be very bright.

The chart shows the view looking east-north-east from London at midnight as 17 November becomes 18 November. This is the night on which the shower is expected to peak but individual Leonids can be seen any time between 3 November and 2 December. Although rates can be as low as 15 meteors an hour, the dust grains that form these meteors are extremely fast. They hit our atmosphere at speeds of about 45 miles (70km) a second, and can be extremely bright and colourful.