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Sheridan Williams, author of the entertaining and informative book, the definitive UK Solar Eclipses from Year 1 takes up the Eclipse story from here:
'It is the first total solar eclipse to be seen in England since 1927. Worldwide, solar eclipses are actually quite common with at least 2 and up to 5 each year. What is rare, and incredibly spectacular, is when you happen to be right in the Moon's shadow during a total solar eclipse. Witnessing totality during a total solar eclipse is so rare that on average you would have to live for 360 years to see one by chance.
A solar eclipse occurs when the Moon gets in the way of the Sun. However, if the Moon only covers part of the Sun (even up to 95%) it is likely to pass unnoticed, unless someone has previously drawn your attention to it and you have some darkened filters to look through. The Moon needs to cover the Sun totally for the full and dramatic effects to be seen with the naked eye.
The Moon varies in apparent size because its orbit is elliptical. At times when it is furthest from the Earth the Moon appears 11% smaller than the Sun and cannot block out the Sun totally from anywhere on Earth. However, when the Moon is closest to the Earth it is over 6% larger than the Sun and hence can totally cover the Sun, provided you are situated exactly at the right location on the Earth. This location is precise because the Moon's shadow on the Earth can be no larger than 170 miles across. In Cornwall in 1999 its shadow will be 65 miles across.
As you can see from an eclipse map, Scilly lies well within the shadow and we will get 1 minute 42 seconds of darkness. Although Scilly will not get the longest amount of darkness (those areas closest to the centre line in Cornwall will only get another 20 seconds!), Scilly will be the first to see the eclipse and have a higher chance of clear skies than the mainland.
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