Sunday, 22 December 2019
This video shows some test footage of the megalithic passage cairn tombs at Loughcrew in County Meath, Republic of Ireland this Winter Solstice taken with an NIR converted Hasselblad camera onboard the DJI Mavic Pro 2 drone.
Clusters of Megalithic Cairns are dotted around the Slieve na Caillaigh hills at Loughcrew, the main concentrations are on Carnbane East where Cairn T is the centrepiece and Carnbane West where Cairn L is located.
The illumination of the passage and chamber at the Winter solstice sunrise in Newgrange is world famous. Less well known is the Equinox illumination at sunrise in Cairn T at Loughcrew. The backstone of the chamber is illuminated by a beam of light at sunrise on the Spring and Autumnal Equinoxes.
The sun light is shaped by the stones of the entrance and passage and descends the backstone while moving from left to the right illuminating the solar symbols.
With Drone-based NIR Imaging, combined with the Soil-Adjusted Vegetation Index (SAVI) it is possible to map certain artificial features in the topography of the land with respect to the vegetation distribution. This allows for the possibility to examine the scale of manmade features such as farmland, burial sites and perhaps settlements that have been buried for centuries and can be difficult to detect using visual maps alone.
The SAVI index is one of many indices used by archaeologists in such research and drone-based imaging offers a unique opportunity to test such techniques affordably and quickly, without the use of more expensive aircraft or satellite imaging techniques. Moreover, the ease of deployment and the high quality of the imaging systems available for drones today makes them superior to other forms of often more expensive aerial surveillance, something which will become a major trend in the future as drone imaging and mapping advances.