The first major solar eclipse to be visible in Britain for 15 years will happen this coming Friday, 20th March. From about 8.40am Britain will be plunged into twilight as the orbit of the moon blocks the light of the sun, peaking at about 9.40am. Unfortunately it will not be a total eclipse, as you would have to travel further north to the Faroe Islands or Svalbard to be lucky enough to view the eclipse in its entirety. But the very least you can see in Britain will be 85%, in the south coast of England, and if you are lucky enough to be at the top of Scotland you could see a 98% eclipse. Where I am in Glasgow, you will be able to see around 92-93%, so it is going to be a pretty special event.
But what exactly is a solar eclipse? They occur when the orbit of the moon comes between the Sun and the Earth, casting a shadow on the surface. The darkest point is known as the umbra, and at this point it is almost as dark as night. This is where you will see a total eclipse, when the sun is completely blocked by the moon in front of it. At this point you can see some spectacular phenomenon, such as the Sun’s Corona, and the Diamond ring effect.
The rest of the Moons shadow is known as the penumbra, and this is where you will see a partial eclipse, so there will always be a part of the sun visible. Total solar eclipses are rare, and only occur every 2 or 3 years, at different points around the Earth. In Britain the last time we had a total eclipse was in 1999, and the next time one will be near will be in 2081, and the next time it will pass directly over us will be in 2090. So this is most definitely a once or twice in a lifetime event, unless you go eclipse chasing around the globe.
A word of caution though, even though a large portion of the Sun will be blocked, please do not stare directly at it without appropriate viewing glasses, as the light is still strong enough to damage your eyes.
If you want to have a preview of what the eclipse will look like at your location, then this website has a really good animation of the eclipse, currently showing the view from Glasgow: