Today, the sun will blaze darkly

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The Independent Online
Today, the words "weather permitting" will matter a great deal. At 3.15pm, the best solar eclipse since 1961 should be visible across much of England and Wales. During today's partial eclipse, starting at about 1.50pm and ending at about 4.25pm, up to 60 per cent of the sun will be covered by the Moon's shadow passing over the Earth.

The worry is that cloudy weather could spoil the event - or, conversely, that clear skies might tempt people to look directly at the sun. "It's the sun's infra-red rays which do the damage," said Duncan Copp of Mill Hill Observatory in London, "Nobody should look at the sun through any sort of optical instrument such as a telescope or pair of binoculars."

Even looking directly at the sun through improvised filters - like fogged photographic film, smoked-glass or a bin liner - is dangerous, as the heat will quickly burn your retina and damage will be permanent. The only sure way is to view the sun indirectly, through a pinhole camera, or else in a reflection such as a windscreen or puddle.

The most indirect view will be over the Internet, at the Society for Popular Astronomy's World Wide Web page, at http://www.u-net.com/ph/spa/ eclipse/partial.htm. But the society also suggests this alterna-tive pinhole projector.

1) Take an empty cereal packet. 2) Make a small pinhole in one of the shorter sides, a couple of inches from the open top. 3) Point the pinhole towards the sun and look inside the box. A small image of the sun will be cast on to the opposite inside wall.

t On 11 August 1999, people in Devon and Cornwall will see a total eclipse of the sun - the last occurring until 2081.

"The Sky at Night'', the Long Weekend, page 2

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