Creevykeel faces slightly south of east, towards the northern edge of Arroo Mountain. At the equinoxes, the midway points between the summer and winter solstices, day and night are of equal length, equinox meaning 'equal-night' in Latin. At the latitude of 54°, where Creevykeel and many of the Sligo megaliths are found, the sun rises at 6.40 am on the equinox.
At Creevykeel, when the sun peeps over the rim of the horizon, it lights up the megalithic facade, making the flecks of quartz and mica sparkle.
The axis of the chamber is oriented to 111°, while the sun rises at 90° or due east. The rising sun flashes obliquely into the left side of the chamber on the equinox, and as the sun rises in the sky the beam of light floods into the second chamber, to touch the back-stone.
The sun flashes into the chamber, creating a golden panel of light, bordered by shadow on each side. The modern 'sill' between the front and rear chamber stops the beam from fully striking the backs-stone ( see photo, above ).
Strangely enough, the backs-stone at Creevykeel is about the same size and shape as the back-stone of Cairn T.
The discovery that Creevykeel, one of the finest examples of a neolithic court-cairn in Ireland, has an astronomical orientation presents a chance to broaden the range of focus in Irish neolithic archaeology and astro-archaeology. Modern aDNA techniques are providing fascinating opportunities to reconstruct the migration patterns of neolithic farmers.
We can say with confidence that Creevykeel was built by descendent's of the European long-house or bandkeramik linear pottery culture, who would have ultimately originated in Anatolia, the home of neolithic agriculture. While the passage-grave people were a maritime people, the bandkeramik followed rivers, and migrated through central Europe along the course of the Danube.
Eventually they arrive in Normandy and Brittany, where, doubtless in competition with the well established passage-grave people and the original mesolithic inhabitants of the region, many take to the seas to colonize the large and sparsely populated islands to the north.