Tomorrow, Friday, the Moon will cast a shadow about 100 miles wide in which the Sun is obscured completely, and the Sun will be partly covered over a much more extensive area.

The event will be a total eclipse for those in the Faroe Islands and Svalbard, surrounding regions of Europe, northern Africa and northern Asia will be treated to a partial solar eclipse.

In Gozo and Malta, an eclipse of type partial solar eclipse will start at 09:20:38, the maximum eclipse will occur at 10:24:55 when the Sun reaches an altitude of 46° and azymuth of 140°; this event will come to an end at 11:33:05 and will have a magnitude of 0.485 (the magnitude of an eclipse is the ratio of the apparent size of the Moon to the apparent size of the Sun during an eclipse) and an obscurity of 0.38 (the fraction of the Sun obscured).

As well as being spectacular events, solar eclipses are also a good opportunity to do some valuable science because they allow observation of phenomena normally hidden or outshone by the Sun’s light.

The solar corona — the Sun’s plasma outer atmosphere — is one such area for study. We normally can’t see the corona (at visible-light wavelengths) since the Sun’s light is too bright, but eclipses provide a chance to get a better look, and astronomers are set to descend on the Faroe Islands and Svalbard in the hope of getting more insight into why the corona is so much hotter than the Sun’s surface.

2015 also marks the centennial of Einstein’s general theory of relativity, which was proven by Arthur Eddington during the 1919 eclipse. Arthur Eddington travelled to the island of Príncipe, off the west coast of Africa, where he took advantage of the solar eclipse to successfully test one of the predictions of Einstein’s general theory of relativity — that the path taken by light bends in a gravitational field, known as gravitational lensing.

Looking directly at the Sun can cause retinal damage, so care must be taken when viewing an eclipse. One way to watch an eclipse safely is via pinhole projection: poke a very small hole through one sheet of white cardboard and let sunlight pass through it and form an image on another sheet.

The image will be brighter when the second sheet is closer to the first and larger when further away – observers can strike a balance that works for them.

Alternatively, an eclipse can be viewed directly using solar filters, which can be bought in the form of glasses. Normal sunglasses are unsafe, however.

Telescopes and cameras will need specially designed, metal-coated solar filters.

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