Make the best of the solar eclipse

IF YOU have not already managed to find a pair of eclipse viewing glasses for tomorrow morning’s partial solar eclipse then you are out of luck as stocks have been sold out across France.

However, you can make a simple viewer very simply and some of the most memorable views are of the crescent sun shapes cast in the shadows of trees.

The eclipse is visible across France and the rest of northern Europe and, depending on where you are in France, will start about 9.30, leading up to maximum coverage at about 10.30 (in Paris) and then it is all over by about 11.40.

The sun will be crescent-shaped; about 80% obscured by the Moon in north-western France, grading down to about 65% in the south-east. The Faroe Isles north of Scotland get the best view as islanders – and the thousands of visitors – will see a total eclipse.

Even crescent-shaped the sun’s light is so strong that it can cause instant damage if you look directly at it. Sunglasses are no use as they do not filter out the extremely damaging invisible UV and infrared rays that can burn your eyes without you knowing.

Opticians and outdoors shops report selling out of eclipse viewing glasses left after a rush at the beginning of this week. If you are lucky, you may be able to find a copy of the science magazines Ciel et Espace and Sciences et Avenir at your newsagents as they have free viewers as a giveaway.

Children are especially at risk and many schools across the country are keeping pupils inside during the eclipse period. Others have organised special sessions with viewing glasses, pinhole cameras or other ways to see the ‘show’.

You can make your own simple viewer with a pinhole camera using two pieces of card and some silver foil (or, for Blue Peter fans, sticky-backed plastic!).

#Eclipse partielle de soleil vendredi 20 mars. Conseils de prudence pour l'observer : http://t.co/ZzQzM5t9vH pic.twitter.com/a2yqW8InSb— L'Etat en Bretagne (@bretagnegouv) March 16, 2015

Cut a hole the size of a euro coin in one card, tape the silver foil on the top and pierce a tiny hole (or several) in the foil/plastic. When the eclipse starts, stand with your back to the sun and hold the holed card up and focus the rays on to the second piece.

Move the second card to get the sun in focus and move it further away to make the image larger.

Try something different with a soup skimmer or colander and see that the sun’s light has been turned into tiny crescents. You can see the same effect if you stand under a tree as the sun shines through the leaves.

If you want to photograph the sun then you must use solar filters as the camera’s captors are as easily damaged as your eye. Unless you have specialist photo equipment including telephoto and solar filters you are not going to get a close-up of the Sun – better to focus on the ground under trees or to capture the way the landscape changes as the light dims.

However, the weather could be set to spoil the party as a large part of the west of France is expected to be under cloud.

See the progress of the eclipse and the timings at these sites ((times are in GMT - add one hour for France) - Time and date and Institut de Mecanique Celeste et de Calcul des Ephemerides (IMCCE)

* The Moon is moving at about 2,250kph as it cross the sun. The eclipse happens when the sun, Moon and Earth are in alignment. The Sun is 400 times larger than the Moon and is also 400 times further away from the Earth, so they appear almost the same size in the sky. The next partial solar eclipse in France is in June 2012, but the sun will only be 20% covered.
* This weekend also sees the grande marée highest tide for 18 years in north-western France, with Saint Malo and Mont St-Michel seeing the tide rise 14.5m. Hotels within 50km of the Channel coast are sold out for the “once in a lifetime event”.
* The Moon will also be on show on Saturday as it is at perigee, its closest approach to the Earth. So the “super Moon” will “appear” larger near to the horizon due to an optical effect.

See previous article: Eclipse to cast a shadow over France