A REVOLUTIONARY flu treatment will be the first drug assessed by a new body recommending which medicines and therapies should be available

A REVOLUTIONARY flu treatment will be the first drug assessed by a new body recommending which medicines and therapies should be available on the NHS. This should not make any difference to the people gathering in Cornwall this Wednesday, because the differences between what is predicted to happen and what actually happens can be measured only with the most precise instruments.Eventually, in many thousands of years from now, total eclipses will be a thing of the past. It is not easy because, for one thing, the orbit of the Earth around the Sun is slightly elliptical, meaning that it travels faster around the star in January than in July.Even minor errors in the positions of the Sun, Moon and Earth can have dramatic effects on the accuracy of an eclipse prediction. Scientists will be monitoring the exact position and timing of totality to compare the actual events, as they happen, with predictions of when they should have occurred. He discovered that the Sun, the Moon and the Earth moved in such a way that after 6,585.32 days (18 years, 11 days and 8 hours) they ended up back in almost the same relative positions.Once the Saros cycle was understood, scientists could calculate down to minutes and seconds when, where and how long the shadow of a total solar eclipse would fall. The ancient Babylonians, or more specifically the semitic people known as the Chaldeans, seem to have come closest to understanding the complicated cycle that determines both lunar and solar eclipses.But the man who really knew about forecasting eclipses was Edmund Halley, the great 18th-century English astronomer who, among other things, gave his name to Halley’s Comet – that other astronomical omen of doom.Halley worked out the basis of eclipse prediction mathematically and called it the Saros cycle, a word he took from ancient Babylonian texts.

The Chinese, in common with many ancient cultures, took eclipses very seriously, believing they were caused by the Sun being devoured by a dragon, which had to be frightened away by making as much noise as it was possible to create.But observing and cataloguing eclipses, which the Chinese were rather good at, is not quite the same as being able to calculate when and where they are expected to appear. And Mark Twain’s hero in A Connecticut Yankee in King Arthur’s Court escaped from being burnt at the stake by, you’ve guessed it, forecasting an eclipse.
Myth has it that two Chinese astronomers, the brothers Hsi and Ho, failed to predict a solar eclipse because of a prior appointment with a bottle or two of wine and lost their heads as a result. A convenient pocket almanac of future eclipses enabled Rider Haggard to rescue one of his heroes in King Solomon’s Mines, who was threatened by a bunch of bloodthirsty natives. Tintin, the cartoon hero, escaped being sacrificed by a tribe of South American sun worshippers by forecasting an approaching eclipse – courtesy of an old newspaper cutting.

THE ABILITY to predict an eclipse has got some people out of tricky situations – and failing to predict them has landed others in serious trouble. The Sun should look quite dim and the sky should be completely black – if this is not the case, do not use the filter,” the group says.People in the zone of totality should only remove their solar filters when the Sun is totally eclipsed – but for no longer than the very point when the Sun begins to re-emerge.. “The safest way to view the eclipse outdoors is indirectly with, for example, a pinhole projection viewer. But if you want to enjoy the full effect of this phenomenon use your TV set,” he said.It is not even safe to view the point of total eclipse, according to the Department of Health, although this advice runs counter to just about every expert body in astronomy.While it is absolutely true that looking at any partial eclipse with the naked eye can, within seconds, cause infra-red radiation to burn the light-sensitive tissues in the retina permanently, astronomers have for many years watched the brief moments of totality without any filters.The UK Coordinating Group on the solar eclipse – which includes the Royal Astronomical Society and the Particle Physics and Astronomy Research Council – advises that it is possible to view the partially eclipsed Sun directly, provided people use a solar filter made of mylar and marked with the “CE” rating of the British Standards Institution.”Hold the special filter firmly over both eyes before looking up at the Sun, and don’t remove it until after looking away. Eye doctors are so concerned about the possibility of people losing their sight through looking at the eclipse that they have issued dire warnings about the dangers of even using recommended sun filters.
Professor Liam Donaldson, the Chief Medical Officer and the Government’s most senior medical adviser, even went as far as to suggest that people should stay indoors if necessary. THERE IS only one piece of advice that everyone agrees on when it comes to observing an eclipse safely – never look directly at the Sun with the naked eye To do so risks permanent eye damage and blindness.

The longest possible period of totality is 7 minutes 31 seconds.Penumbra: The shadow caused by a partial solar eclipseUmbra: The shadow of totality caused when the Moon completely blocks our view of the Sun.. Third Contact is when totality ends and the Sun makes its reappearance, and Fourth Contact: The point when the Moon passes completely away from the Sun.Saros Cycle: The complicated pattern of lunar and solar eclipses that repeats itself every 6,585.32 days, named by Edmund Halley, the great 17th Century English astronomer, who took it from a Babylonian word.Totality: The point when the Moon completely blocks the Sun. This point – the Third Contact – will mark the end of the last solar eclipse of the millennium.GlossaryBaily’s beads: Bubbles of sunlight breaking through the deep valleys of the Moon in the final moments before and after a total eclipseCorona: The Sun’s outer atmosphere which extends for millions of miles into space and appears as a halo around a totally eclipsed Moon.Diamond Ring: The twinkling of the final bead of sunlight immediately before or after a total eclipseFirst Contact: The point when the Moon begins to take a “bite” out of the Sun Followed by Second Contact, the point when totality begins. A halo of light, the Sun’s corona, will give a saintly glow to the black lunar face. A dim, eerie glow will descend around those experiencing totality on the ground and an array of colours will dance around the entire horizon like no other sunset on Earth.The ghostly aura will end with a flash of another Diamond Ring, followed closely by a second set of Baily’s beads. After these “Baily’s beads”, a final and intense sprinkle of brightness, called the Diamond Ring, will cause the final flashes of sunlight to stream through the mountains on the Moon’s horizon.Here, totality begins, the point known as Second Contact, which is timed to occur at eleven minutes past the eleventh hour on the eleventh day of August.For about two minutes the Sun entirely disappears behind the Moon.

The Sun’s heat dies away, the colours fade and birds maybegin their night-time rituals – evensong in the morning.Just before totality, when the Sun is reduced to a thin crescent, the sky blackens quickly and the horizon to the west darkens ominously as the shadow of the Moon races silently forward at twice the speed of sound.Temperatures can fall with the rapidly cooling atmosphere, producing a set of “shadow bands” or air currents that appear as parallel ribbons of light and dark across the ground. If the sky is clear and cloudless, it should be possible to see the stars and the brightest planets, such as Mercury and Venus.Seconds before totality – the point known as Second Contact – the last few shafts of sunlight will sparkle against the edge of the lunar disc as the Sun shines through the deep valleys of the Moon. This is called a lunar eclipse and, unlike a solar eclipse, can be seen at any point on Earth where the Moon is above the horizon.On Wednesday, the umbra of the Moon will be travelling at a speed of about 2,000mph as it crosses the globe from west to east, starting in Nova Scotia, passing through Cornwall, south Devon, Alderney in the English Channel, northern France, across Romania, Turkey and Iran before fizzling out in the Bay of Bengal.Although the Moon’s umbra will be no more than a few hundred miles wide, the accompanying penumbra (and the partial eclipses it produces) will be nearly 3,000 miles across.For those lucky enough to be in the path of totality, events in the South West will begin to unfold a few minutes before 10am, when the Moon begins to take a bite out out the top right-hand corner of the Sun – the point known as First Contact.As the minutes unfold and the bite begins to get bigger, it may take another 45 minutes before a noticeable change in colour and light intensity begins to occur.At about 15 minutes before totality the drama of a total eclipse starts to unfold. More rarely, the whole Sun is obscured, and the shadow’s full “umbra” cuts a swath across the globe, allowing everyone in its path to experience a total eclipse.When the Moon is full, and lies behind the Earth, it is the turn of our own planet to cast a shadow on our natural satellite.