Watch the partial eclipse of the Moon

Two weeks after the solar eclipse, there is a chance to see a very large partial eclipse of the Moon from the UK and Europe on the evening of Saturday 16 August. The Moon rises over Britain with the eclipse already underway. First contact with the pale outer shadow, the penumbra, takes place at 18:25 UT (7.25 pm BST) when the Moon is still below the horizon for UK observers. When the Moon finally does rise above the southeastern horizon at around 19:30 UT (8.30 pm BST), it is almost wholly immersed in the penumbra. Minutes after moonrise from much of the UK, it begins to enter the main dark shadow, called the umbra. First contact with the umbra occurs at 19:36 UT (8.36 pm BST). By 21:10 UT (10.10 pm BST) the Moon is immersed at its maximum depth in the umbra, leaving a sliver of the northern limb shining in the penumbral light, while more than 80 per cent of the lunar disk has assumed a deep red hue. The Moon is then around 13° above the southern horizon for observers in southern England, in the southern constellation of Capriconus. The Moon finally leaves the umbra at 22:44 UT (11.44 pm BST) and exits the penumbra at 23:55 UT (12.55 am BST). The Earth's shadow is actually composed of two cones, one darker one within the other. To understand the geometry of this, and the difference between the umbra and penumbra, visit this webpage. This will be the deepest lunar eclipse visible from the UK until 15 June 2011. A webcast of the eclipse will be broadcast by noted astronomy author Peter Grego live from St Dennis, Cornwall, between 19:30 UT (8.30 pm BST) and 22:45 UT (11.45 pm BST) at www.lunarobservers.com. You can observe for yourself with the unaided eye but steadily-held binoculars will help you to follow the shadow's progress across the Moon's face. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.

Perseid meteors are gold medal event

After the spectacular opening fireworks of the Chinese Olympics comes one of nature's own finest displays - the Perseid meteor shower. In fact Earth began entering the dust stream that produces these shooting stars in July. But they will build to a peak in mid August when a single observer might see one or more a minute. The Perseids are dust particles ejected from Comet Swift-Tuttle which flare brilliantly as they enter the Earth's upper atmosphere and "burn up". They are one of the year's most reliable showers and a favourite for northern stargazers who can sit out and count them on warm summer nights. The meteors are expected to build to a rate of 80-100 an hour at maximum on 12 August - that is the number one might be expected to see with the unaided eye under ideal sky conditions if the radiant were directly overhead. The radiant is the point in the sky from which the meteors appear to diverge - an effect of perspective much like the way parallel lines of a rail track appear to converge into the distance. It lies in the constellation of Perseus which gives the meteor shower its name, but the meteors themselves can be seen in any part of the sky. The radiant is low in the sky when darkness falls but climbs steadily through the night and highest rates are likely to be seen in the early hours. Although the 12th is the night of maximum, it is worth watching on nights around that date too when rates are expected still to be very respectable. The waxing gibbous moon is low in the sky from mid-northern latitudes, setting around midnight. Conditions could therefore be ideal in the pre-dawn hours. The Society for Popular Astronomy meteor section reports that a Finnish meteor expert, Esko Lyytinen, believes that the Earth may encounter a denser meteoroid trail for perhaps an hour or so centred on 05h26m UT on 12 August. He suggests this could give another peak of 100-300, or even higher. The timing could particularly favour US sky-watchers. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA, the UK, Canada and France. They are powered by Amazon so you can buy with confidence.