Due to adverse weather conditions on the 20th, 21st and 22nd of March there was no spring equinox sunrise to illuminate the chamber of Cairn T. The sunrise on the March 23rd looked like it might be hampered by mist, thankfully it turned out to be a perfect sunrise to illuminate the backstone of the chamber in Cairn T.

6:30am - The sunbeam in the chamber of Cairn T before it reaches the backstone.




6:40am - The sunbeam creeps onto the backstone of Cairn T.




6:50am - The sunbeam moves across the backstone. The dark patch at the bottom left of the image is a shadow from part of the iron gate surround at the entrance to the cairn.




6:53am - the most impressive stage of the illumination on the backstone.




6:58am - the sunbeam moves across and down on the backstone.




7:06am - the sunbeam continues its journey across and down the backstone




7:12am - beam of equinox sunlight illuminating the bottom right corner of the backstone.

7:19am - the sunbeam near its lowest point on the backstone.




7:23am - the sunbeam just before it moves off the backstone.

Video of the event which has been compressed from 50 minutes to 40 seconds. The file is just under 2mb in size and is in WMV format (Windows Media Video).

Light Years Ago by Tim O'Brien shows that the symbols of the sun engraved on the backstone of Cairn T at Loughcrew are precisely positioned to measure solar movement. A beam of light from the rising sun around the time of the March and September equinoxes is mapped on the backstone. Purchase book at Amazon.com, purchase book at Amazon.co.uk