Samhain Moon

My last post was very appreciatively tweeted by Vox Hiberionacum with the following line: ‘Gorgeous pics and potentially fascinating alignment if true’.
With it he clearly identified a very important aspect of the lunar alignment at the Grianán – it has to be established, that what happened at the October moon was not just a one off occurrence and evidence has to be provided, where there is so far only intriguing conjecture.
But as so often, that would proof to be more difficult than anticipated. Not only had the by now distinguished cloud cover to be taken into account but also the very confusing movements of the moon. After a fascinating and in equal measurers disheartening conversion with Gerry Moran and Paddy Rathbone (both Buncrana Camera Club) back in October, concerning the complexity of the moon, I came to the conclusion, that the Hopi’s description of it is a very polite one and that I have to resort to the ancient practice of observation and see what will happen in the hope that the original builders correctly calculated the perfect position of the monument with the alignment still and partially working, no matter where the moon will rise in the run up to the minor lunar standstill.

How drastic the point of moonrise can change became clear in early November as its position moved from the east on November 4, by some considerable degrees to the northeast on November 7. Such radical swing altered the angle of light entering the entrance and the width and length of the beam. While on the first occasion, and the very short opportunity to capture it, the northern wall of the entrance was illuminated, on the second sighting the southern side was lit. The beam also had changed position as well as size and shape. With the moon moving even further north in December, the light may not reach beyond the end of entrance and stretch inside of the monument.

Here is one link that may explain the ‘wobble’ of the moon:
Lunar Alignments in Early Bronze Age Scotland/Key Lunar Declinations

November 4, 6.13 pm. The moon light approaching the inside of the monument.

November 4, 6.13 pm. The moon light approaching the inside of the monument.


November 4, 6.23 pm and a round of cat and mouse. The lights at the entrance are a reflection, coming from Derry.


November 4, 6.41 pm.


November 4, 6.49 pm.


November 5, 5.59 pm. Very murky sky and hence a very veiled moon. This is a far as it went with no beam appearing at all.


November 7, 7.04 pm. The moon light has made it nearly all the way through the entrance.


November 7, 7.08 pm.


November 7, 7.15 pm and a thin, sword like beam appeared.


November 7, 7.19 pm.


November 7, 7.26 pm.




November 7, 7.43 pm.


November 7, 7.57 pm. At this stage the beam was at its widest but retreating nevertheless.


5 thoughts

  1. I tell you what, regardless of prehistoric intent, that would have been one naturally spectacular ‘theatre’/’performance arena’, both day and night time, during the early medieval. Imagine a crowd below looking at figures elevated on wall, silhouetted against the back lit sky.

    Reminds me of Dun Aonghus on Inis Mor: A natural sunset ‘theatre’ facing west, but moonlit would have been quite different.

    • Being inside the monument in particular, one can not help to be reminded of an amphitheatre. And the way sound works at Grianán is very fascinating. When standing on the ground I do not need to shout, just to raise my voice, when conversing with someone on the top. And when standing on the top platform a chat between two people can clearly be heard by someone who walked a short distance away from the monument. Strangely enough, an old coach from the 70’s, huffing and puffing up the road to the car park and despite all the noise of the engine, can not be heard approaching.
      The full or nearly full moon light is actually not so different than the sun. It is fainter since it is reflected and of course you have the stars with the milky way running right across the monument.Shadows work just fine, see photo below from the October moon.

      • That’s one of the best phenomenological descriptions and round ups of Cashel attributes I’ve read in a long time…

        Aside from alignments, I think you are doing valuable service to how we should think about ‘public performance’ of kingship in early med ireland. Mounds, Barrows, Standing Stones get all the attention, especially inaugurations and laws, but what about more regular mundane events? Annual render/tribute and gifts, external negotiations, hostages, visiting traders…the public performance and visibilityof these gatherings would have been an integral part of proceedings.

      • Much appreciated, Terry.
        Grianán can be seen, apparently intact, on one of Thomas Raven’s maps of Derry from 1625. Which leaves the question if the O Dochartaighs, who moved to Inishowen in the 14th century, made any use of the monument. But they didn’t write much down. I have not been able to trace any record in their own words about their time here. Any earlier account of the monument, which could give clues as to the use of it, is equally non existing and only mentioned under its possible older name of Carrick (Carn/Ard) Eolairg.

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