Astronomers Gear up for Great Partial Solar Eclipse

Eclipse 2015

Development of the 20 March 2015 partial solar eclipse as seen from Northern Ireland from first contact at 08:26 to eclipse maximum at around 09:30. The upper panel shows the eclipse increasing from First Contact at 08:26 to eclipse maximum; the lower panel shows the Moon moving away from the Sun towards the end of the eclipse at Fourth Contact, which occurs at 10:39 (as seen from Belfast). These images have been extracted from the excellent UKHO website (also see further links from UKHO). Click on image to enlarge.

Armagh Observatory reports that the largest partial solar eclipse visible from Northern Ireland since 1927, when 97 percent of the Sun’s disc was obscured, occurs between 08:26 and 10:38 on the morning of Friday 20 March 2015. This partial eclipse is the first such eclipse visible from Northern Ireland since 1 August 2008, when less than 20 percent of the Sun was obscured. This year, at eclipse maximum around 9.30am on 20 March, the Moon will eclipse more than 93 percent of the Sun’s disc, leaving just a thin crescent-Sun or "smiley" uncovered.

Partial eclipses of the Sun are not particularly rare, being seen from a single location such as Northern Ireland about once every three years, on average. However, deep partial eclipses, such as the one this year, are much rarer, occurring on average just once or twice in a human lifetime. The next comparably deep eclipse will not occur until 12 August 2026, and after that observers in Northern Ireland will have to wait until 23 September 2090 before they can see a similarly deep eclipse to that this year, which coincidentally occurs on the Spring Equinox.

This year’s partial solar eclipse is therefore a rare and unusual event, and every effort is being made to observe it safely and record its appearance and any associated environmental effects that might be seen. As with all time-critical astronomical events, we can only hope that the weather will cooperate and produce clear skies.

Astronomers across the island of Ireland are preparing to observe the eclipse, and some are hosting special eclipse parties to show school groups and the general public the fascinating phenomenon. Armagh Observatory will be opening its doors from 8.30am on the morning of the eclipse to explain the event and to show people how to observe the eclipse safely.

On St Patrick’s Day, a few days before the eclipse, the Observatory will also be hosting a Free public lecture at 11.15am in the Studio Theatre, the Market Place, “The Irish Sun and the Great Solar Eclipse of 20 March 2015”, by Dr Eamon Scullion of Trinity College Dublin.

This will be followed at 2.30pm, also on St Patrick’s Day, by Free guided tours of the Observatory and guided listenings of a new outdoor public exhibit, called “aroundNorth”. This is a unique sound installation that demonstrates the apparent rotation of stars around the North Celestial Pole.

Those who wish to learn more about the Great Partial Eclipse and other events taking place in association with the eclipse around mid-March are advised to consult the Observatory’s website or contact the Observatory to obtain free tickets to the public events. Full information on the eclipse is available at and this leaflet, while full information on the St Patrick’s Day events can be found here.


Irish Eclipse Website at

Armagh Observatory Eclipse 2015 Leaflet - PDF

Weather at Armagh during the partial eclipse of 29 June 1927 - PDF

Ordnance Survey map showing path of partial eclipse of 29 June 1927

Solar Eclipse Safety Code from the British Astronomical Association

How you can take part in a scientific experiment

FOR FURTHER INFORMATION PLEASE CONTACT: Mark Bailey at the Armagh Observatory, College Hill, Armagh, BT61 9DG. Tel.: 028-3752-2928; FAX: 028-3752-7174; mebat


There is very little tendency under normal circumstances to look at the Sun in a way that might damage the eye, especially as the Sun is so bright that it is difficult to stare at it directly. However, during a large partial eclipse the Sun is the centre of attention, and with so much of the Sun covered it is tempting and slightly easier to stare at it. NEVER DO SO. It is NEVER safe to look at the Sun without proper eye protection. Failure to use proper observing methods can result in permanent eye damage and severe retinal loss.

The principal causes of eclipse-related retinal burns are (i) viewing the partially eclipsed Sun without suitable eye protection; (ii) looking directly at the Sun through the pinhole of an indirect projection viewer; and (iii) viewing the Sun through ordinary sunglasses, photographic neutral-density filters, or a wide range of similarly inappropriate devices.

Last Revised: 2015 March 16th