The only total eclipse of the year is taking place on 20/21 February. It will be visible across South America, most of North America, and Western Europe and Africa.

For those in the UK, this eclipse is one for the insomniacs among us. The partial eclipse, when the Moon is partly cast in the Earth's shadow, begins at 01:43am on 21 February. The total eclipse itself starts at 03:01am, when the Moon is in the full shadow of the Earth. This lasts until 03:51am, with the mid-point of the eclipse at 03:26am.

Total lunar eclipses are relatively rare events, occurring at most only twice each year, because they depend on the Sun, Earth and Moon being exactly aligned on a plane.

What happens during a lunar eclipse?

As seen from the Earth, there are only two points (called 'nodes') where the orbits of the Sun and Moon intersect. If the Moon is full when it and the Sun are both at these nodes together, then we will experience a total eclipse.

Towards the mid-point of the eclipse, observers might see the Moon turn a dark red colour. This 'Blood Moon' occurs at the height of the eclipse. Sunlight is refracted as it passes through the Earth's atmosphere. Dust and pollution in the atmosphere scatter the higher wavelengths, meaning that only the lower, red wavelengths in the Sun's light are able to pass through the atmosphere. This light then passes on past the Earth and shines on the Moon behind, illuminating it with an ominous red colour.

Eclipses are easy to predict, and almanacs have carried dates and times of such occurrences for hundreds of years.

Eclipse legend

One legend associated with the prediction of eclipses concerns Christopher Columbus. On his fourth journey to the New World, his ship was badly damaged and not seaworthy. He landed at St. Anne's Bay in Jamaica, and spent more than a year there waiting for assistance from his fellow voyagers.

When he landed, the Jamaicans were initially welcoming and friendly, and provided Columbus and his crew with food, supplies and shelter. Columbus' crew took advantage of the generosity, however, and eventually the islanders decided to withdraw their aid. With his crew on the verge of mutiny and about to attack the islanders and take what they wanted from them, Columbus asked for a meeting with the islanders' chiefs.

At sunset on 29 February, 1504, Columbus and the islanders' leaders met. Columbus told them that god was angry with their decision to stop helping the sailors, and he would show his anger by taking the Moon from the sky.

Columbus was reported to happen to have an almanac with him. As the full Moon rose, no doubt the chiefs dismissed Columbus' claims, but then, as Columbus knew it would, a total lunar eclipse began.

No doubt all there had seen eclipses before, but that Columbus could apparently wield such power to summon one at will must have terrified the islanders there. They pleaded with him to stop the eclipse, and offered him whatever he wanted in return.

Columbus retired to 'consider the offer', and returned as the eclipse began to end, saying that he was satisfied with the offer and had asked god to return the Moon, which duly returned to its usual brilliant self.

Learn
- For more on eclipses and space in general, visit the Discovery Guide to Space.

Play
- Defend the Earth from certain doom in Comet Impact.