Remarkable discovery which connects a 4,000-year-old tomb in Kerry with the equinox

The Dingle Peninsula (Irish: Corca Dhuibhne) is a peninsula that juts out into the Atlantic Ocean and is in County Kerry ( Contae Chiarraí)) in the south-west of Ireland. Its stunning Atlantic coastline, mountains and lakes make this area among the most scenic in Ireland. The area is rich in history, with many internationally recognised sites of importance. A significant number of ancient monuments are located in the area around the valley of Loch an Dúin on the eastern side of the Conor Pass. One of which is known as the Giants Grave, a 4000 year old tomb which contains within it ancient rock art, including a cup and circle near the head of the tomb. 

Now the Giants Grave has been the focus of attention following a discovery that links the tomb with the equinox. The Equinox occurs twice a year when the plane of the Earth's equator passes directly through the centre of the Sun's disc. During an equinox, night and day are approximately the same duration. As reported by Irish broadcaster Raidió Teilifís Éireann (RTÉ): " For the past 14 years Daithí Ó Conaill, a retired school principal, has visited the site during the winter and summer solstice hoping to make a connection between the tomb and the sun." However, his observations have now shown that the wedge tomb is aligned to the setting sun of the equinox, the last of which happened on 22nd September. 

When the sun sets into a valley in the Brandon mountain range, some distance from the site, a shaft of light enters the wedge tomb, illuminating the chamber and the rock art at the head of the tomb. The discovery has highlighted the remarkable skill of those ancient people who constructed it. Archaeologist Míchéal Ó Coiléain who has carried out extensive surveys in Loch an Dúin said : "Daithí's discovery is wonderful and it goes to show that people living 4000 years ago are aware of movements of the sun. They are agricultural communities, so to know when the longest days of the year, the shortest, and when the equinoxes fall is so important. To construct such a perfectly positioned monument required remarkable expertise and knowledge."