An animated optical projection inside the Dwarfie Stane during fieldwork in 2015. Photo: Aaron Watson

Archaeo-optics introduction

'Archaeo-optics' is a research collaboration between myself, Ronnie Scott and Matt Gatton. It explores how optically projected light may have been manipulated, experienced and understood by people throughout time. Since 2012 I have conducted experimental fieldwork at many Neolithic chambered monuments, revealing how they can generate colourful moving projections that are reminiscent of cinematography. A remarkable variety of dynamic effects have now been observed and, where possible, recorded. They include beams of light, blazing orbs, spectral figures and luminous animated images of landscape and people. 

An enlarged optical projection of the sun's disc inside Bryn Celli Ddu, Anglesey, during midsummer sunrise in 2015. Photo: Aaron Watson

Archaeo-optic phenomena are especially effective at passage graves because they reproduce the fundamental format of a camera obscura. The restricted single entrances govern the movement of light to such an extent that only simple refinements are needed to manifest a visible image. Some sites even have original built-in features that may have served this purpose. At others the effect can be achieved by using an opaque screen punctured with a small hole — the aperture.

An animal skin being used as an aperture screen during fieldwork at Bryn Celli Ddu in 2015. Photo: Aaron Watson

By changing the diameter of the aperture, or its distance from the wall where the projection will appear (the focal distance), the character of the image can be adjusted. The dark chambers of these monuments provide the perfect venue within which optical projections can be witnessed, but their extended passages allow the size, brightness and focus of projections to be closely controlled. Like all images produced by a camera obscura, the image is both upside down and back to front.

An inverted human figure projected upon the back wall of the chamber at Cuween Hill during fieldwork in 2015. Photo: Aaron Watson

While these experiences are striking in the present day, I am especially fascinated by how they might have been manipulated and understood in the past. Neolithic people did not share our modern scientific knowledge of optical physics, and could only have explained these striking and unique effects using their own frames of reference.

Archaeologists now interpret passage graves as potent places where people engaged with alternative dimensions and journeyed between the realms of life and death. Might such meanings have been enhanced, and even made real, in the presence of projections? Coupled with powerful archaeoacoustic effects, the sensory experience of passage graves could have been both powerful and extraordinary.

Archaeo-optics fieldwork

Since 2012 I have been undertaking archaeo-optic fieldwork and observations at many monuments, including Bryn Celli Ddu, Cuween Hill, Wideford Hill, Vinquoy Hill, Dwarfie Stane and the Grey Cairns of Camster. Research is ongoing at these and other sites. Further information will be uploaded to this site as the research progresses.


Further reading

Watson, Aaron and Scott, Ronnie. In press. Materialising Light, Making Worlds: Image projection within the megalithic passage tombs of Britain and Ireland”. In Constantinos Papadopoulos and Graeme Earl (eds.) The Oxford Handbook of Light in Archaeology. Oxford: Oxford University Press.

Links to additional information

Matt Gatton's wide-ranging and fascinating research into the use and meaning of optical projections throughout time, from the present day to the Palaeolithic: