Partial solar eclipse: why half the sun will disappear over Northern Ireland on Saturday morning

A solar eclipse occurs when the Moon passes between the Earth and the Sun, blocking our view of the solar disc.

If it passes directly in front of the Sun we see a total solar eclipse, (or an annular solar eclipse, if the Moon happens to appear a bit smaller than the Sun as we see it). If the shadow passes just to one side of our location, we see a partial eclipse.

This eclipse will not be a total one anywhere on Earth, as the main shadow of the Moon passes the planet just off north east Canada.

Throughout Ireland, the eclipse begins within a few minutes before or after 10am, maximum is within a few minutes before or after 11am, and it ends within a few minutes of 12 Noon.

According to the Irish Astronomical Association (IAA), the magnitude of the eclipse (the fraction of the diameter of the Sun’s disc which will be covered by the Moon’s shadow), will be more than 50 per cent all over Ireland, with Belfast getting 52.3 per cent and north west Mayo getting almost 57 per cent. Dublin gets 51.4 percent; Derry / Londonderry gets 54,3 per cent; Galway gets 54.6 per cent, Belmullet gets 56.5 per cent, and the western tip of Achill Island gets the most in Ireland, with 56.6 per cent.

The IAA explained that the further west you are on the island of Ireland, the more of the Sun will appear covered by the Moon (clouds permitting), and the earlier the eclipse will start. For example, at Belfast, it starts at 10h 03m 40s, but at Belmullet in Mayo, it starts at 09h 58m 41s.

Unfortunately due to weather conditions, two public observing events organised by the IAA for this eclipse, one in Clandeboye near Bangor and one at the Ulster Museum in Belfast, have been cancelled. All indoor activities at the Ulster Museum will still go ahead.

The IAA said it is very important that you do not look at the Sun, even during this eclipse, with your own eyes, and especially not through any sort of binoculars or telescope, as there is a serious risk of permanent eye damage or blindness. If you are not sure about any equipment you may have, do NOT use it.

Obviously the eclipse can only be seen if the sky is clear.

The IAA said that because the uneclipsed portion of the Sun is just as bright as usual, it is not a good idea to try to image the eclipse without special equipment, or you risk seriously damaging your camera.