The equinox illumination of Loughcrew Cairn T is a remarkable phenomenon where sunlight aligns with the passage and chamber of the ancient megalithic structure during the equinox. Specifically designed to capture this celestial event, Cairn T at Loughcrew becomes illuminated as the sun rises, casting light down the passage and into the chamber.

The precision in the construction of Cairn T allows for this captivating play of light and shadow during the equinox, creating a stunning spectacle that underscores the ancient builders' astronomical knowledge and architectural expertise. The event serves as a testament to the alignment of ancient structures with celestial events, possibly having symbolic or ritualistic significance for the people who constructed and used these monuments.

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.