Eclipse shines a light on pollution

Environmental campaigners joined thousands of amateur stargazers to watch last night's total eclipse of the moon. Both groups planned to use the dramatic event to determine the effects of light pollution in Britain.

Both the Campaign to Protect Rural England and the British Astronomical Association urged observers to report the disruptive effects of lights from golf driving ranges, ferry terminals, airports, prisons and service stations as they watched the moon's disc darken as it passed through Earth's shadow. Neon and sodium lighting have been accused of turning the night sky into an impenetrable grey fug.

The eclipse - which occurs when the Sun, the Earth and its moon form a near-straight line - was due to begin at 11.30pm before ending around 3am today. Although not as striking as solar eclipses, lunar eclipses - which can only occur when the moon is full - are still dramatic spectacles. The moon does not become invisible but is turned deep brown, coppery-red or orange, the exact colour depending on the amount of dust and cloud in Earth's atmosphere.

At the height of the eclipse, faint stars, normally drowned out by moonlight, should suddenly re-appear in the night sky. Or at least that is what people used to see. In recent years, this effect has been ruined because of light pollution, and it is this effect that green campaigners and astronomy groups were asked to monitor last night.

Last month, the select committee on science warned that half the population of England will never see the Milky Way because of light pollution. Eighty per cent of the amateur astronomers contacted by the select committee said they could not see the Milky Way from their homes. More than half had to travel between five and 50 miles to see it and some even further. Now results from watching last night's eclipse will be added to this database.

'I think it's a deprivation if people can never see a really dark sky,' said Sir Martin Rees, the Astronomer Royal. 'We should think of the sky as part of our environment and just as we're concerned not to degrade the landscape, we should make it possible to see a really dark sky without having to go off to some remote part of Scotland.'