Loughcrew Equinox - 20th September 2009
On Carnbane East at Loughcrew, Cairn T is aligned with the rising sun at the equinoxes, when light enters the chamber and illuminates the carvings within. The photographs below record the autumn equinox on 20th September 2009, when a clear sunrise filled the chamber with golden light.
Loughcrew Cairn T - Equinox Sunrise
Staff from the OPW (Office of Public Works) were in attendance at Cairn T, Loughcrew on the morning of Sunday the 20th of September. All those who made the effort to get up early on a Sunday morning were rewarded by a glorious sunrise that illuminated the backstone inside the chamber of Cairn T.
Clare and Leontia arranged an orderly queue both sides of the entrance and allowed groups of 5 or 6 to enter from alternative sides. The atmosphere was friendly and relaxed and everybody got to spend time in the chamber and witness first hand the illumination of the backstone. Staff from the OPW will be at Cairn T on Monday the 21st September and Tuesday the 22nd September from 7.15am until 8.30am.
Sunbeam on the backstone of the chamber inside Cairn T at 7:40am on 20th September 2009
View from inside the chamber of Cairn T at 7:40am on 20th September 2009
Loughcrew Video - Spring Equinox 2005
The progress of the sunbeam on the backstone inside Cairn T at Loughcrew was video recorded at sunrise on the morning of March 23rd 2005. The 50 minute video has been compressed to 1 minute 46 seconds and included in the following YouTube Video.
The Equinox Alignment at Cairn T
Like the famous winter solstice illumination at Newgrange, the sunrise at Cairn T was deliberately incorporated into the monument's design by its Neolithic builders over 5,000 years ago. Around the spring and autumn equinoxes, the rising sun shines directly along the passage and into the cruciform chamber, where a beam of light slowly illuminates the richly decorated backstone. The display lasts for approximately 50 minutes as the beam gradually moves across the carved stone.
The backstone is among the finest examples of Irish passage tomb art, covered with concentric circles, radiating lines and other abstract motifs whose meaning remains uncertain. As the sunlight advances across the surface, carvings that are barely visible in ordinary light emerge in striking relief, demonstrating the remarkable precision with which the monument was aligned to the rising equinoctial sun. Archaeologists regard the illumination as one of the most significant examples of prehistoric solar alignment in Ireland.
Still photograph from the Spring Equinox illumination, March 2005.
The modern rediscovery of the Cairn T alignment is credited to Martin Brennan and Jack Roberts, who documented the phenomenon in 1980. Brennan later described the alignment in The Stars and the Stones, subsequently republished as The Stones of Time. His observations brought renewed attention to Loughcrew and encouraged further archaeological and archaeoastronomical research into Ireland's passage tombs. While some of Brennan's broader interpretations remain the subject of debate, the equinox illumination itself is now well established.
On 21 September 2008, mist and cloud allowed only brief glimpses of the light inside the chamber, while the following morning produced a spectacular illumination recorded on 22 September 2008. Similar conditions occurred during the 2009 equinox, illustrating why visitors return year after year in the hope of witnessing this rare interaction between sunlight, stone and prehistoric art.
The wider Loughcrew cemetery extends across three hilltops in County Meath and contains more than thirty passage tombs, making it one of Ireland's four great Neolithic passage tomb cemeteries. Explore more of the site at Loughcrew photo gallery.