This afternoon I joined a field trip to the Broch of Mousa, sited on an island a short boat journey from the east coast of Mainland, Shetland.

Today, the site is visited by a specialist to assess its potential for Optically-Stimulated Luminescence dating. On the theme of light, I also make some observations about the qualities of tree shadows on this sunny day.

Earlier this week I presented my first research paper about Neolithic optical effects at the Theoretical Archaeology Group conference, hosted by Cardiff University.

Autumn sunshine reflects upon the ocean at Kilmory and I see sun dogs and a halo.

Having just completed our fieldwalking survey near Golspie, I was joined by Richard Bradley, Ronnie Scott and Annette Jack on a visit to the Ferrycroft Visitor Centre and heritage trail in Lairg.

More fields investigated, along with a visit to a chambered cairn and Dunrobin Castle Museum.

Roughting Linn is the name of both an impressive rock art site and a lively waterfall.

I recently had the opportunity to experiment with optical projections at the spectacular Neolithic passage grave cemetery of Carrowkeel.

Following our dawn observations at Cuween Hill, Ronnie and I went straight to to the port of Stromness for the return journey across the Pentland Firth.

Our final morning in Orkney was clear and bright, so once again Ronnie and I headed for Cuween Hill to watch the dawn.

After a dull morning at Cuween Hill, Ronnie and I took advantage of some afternoon brightness to go in search of outcropping quartz near the Tomb of the Eagles.

It was difficult to read the pre-dawn skies above Stromness this morning. So, just in case it cleared, Ronnie and I headed out to Cuween Hill cairn in the early hours.

Wet and cloudy weather today in Orkney, so Ronnie and I took the opportunity to visit Stromness Museum.

Clear skies over Orkney this morning allowed Ronnie and I to record projections of the solar disc inside Cuween Hill chambered cairn at dawn.

After dawn at Cuween Hill this morngin, continuing clear skies over Orkney encouraged Ronnie and I to visit the Tomb of the Eagles in the afternoon.

Back on the Mainland of Orkney we are planning observations at several sites over the next week. Today, we visited Wideford Hill at dusk.

Ronnie and I departed Hoy this morning. There's been quite a change in the weather today, with blustery winds and overcast skies.

As it was dry and reasonably bright Ronnie and I explored the landscape around the Dwarfie Stane, including other large boulders nearby.

Blue skies in Hoy this evening. The landscape was glowing as Ronnie and I once again walked to the Dwarfie Stane to project the setting sun.

It's an overcast afternoon in Hoy, ideal for recording the Dwarfie Stane in 3D using structure from motion photogrammetry.