Willem F.M. Beex1/John W.M. Peterson2
1 ARC-bv and National Museum for Antiquities, Amsterdam, The Netherlands
2 School of Information Systems, University of East Anglia, Norwich, UK

Neolithic and Bronze Age henges may be related to particular solar events, but confirmation of this requires an accurate determination of relative orientations. In the case of the Arminghall henge in Norfolk, England, the direction of mid-Winter sunset was thought to have had an important influence, but our computer based methods reveal flaws in this proposal.
We initially developed a spreadsheet relating archaeo-astronomical data to a horizon profile (created manually) and the orientation of the henge (derived from rectified aerial photography). Subsequently we have created a more accurate, useful and convincing visualisation. This is a virtual reconstruction, based on a digital terrain model and the excavation plan, of the midwinter sunset for 4,000 years BP. From this we can suggest that the henge is positioned so that the setting sun is visible "rolling down" the side of the most prominent nearby hill. However, it is also clear that the axis of symmetry of the central wooden structure points in a slightly different direction, towards the top of the hill. Virtual reality reconstruction thus allows alternative theories to be explored. It also provides a stimulus to further investigation of the landscape setting of similar structures.
Keywords: VR, henge, orientation, DTM/DEM-processing