A Standing Stone above Finlaggan. This structure and other standing stones on Islay probably pre-date the medieval ruins on the Council Isle by around two or three thousand years.
Someone on Islay raised a question about whether any of Islay's standing stone groups have solar alignments, as can be read in an article about the Winter Solstice. I know of several sites on Islay which have been linked to various astronomical events. These include the stone circle at Cultoon, the standing stones at Ballinaby and the standing stone at Finlaggan.
The study of astronomical practices in ancient cultures is known as archaeoastronomy. The idea of ancient monuments having some kind of astronomical function has been around for a long time but from the middle of the 20th century the subject became very popular and since the 1980's work has been undertaken by scientists with backgrounds in both archaeology and astronomy.
The night sky would have looked slightly different in the Neolithic and Bronze Ages due to what astronomers call precession. In simple terms this is the 'wobble' of the Earth about its axis, with the 'wobble' taking 26,000 years to come back to where it started. The position of the stars changes in relation to the Earth over these 26,000 years.
The Cultoon stone circle, actually an ellipse, was abandoned before completion in the first half of the first millennium B.C. The climate was deteriorating during this period and the peat bogs were growing. Perhaps constructing stone circles became a luxury that the builders could not afford and they had to put their resources into survival. The site was excavated by Euan MacKie in the 1970's and it was found that most of the stones had never been put in place.
Looking to the south-west along the major axis of the ellipse, marked by a fallen stone and a hole where a stone would have been, it is possible to see the Irish mountain Slieve Snaght. Looking along this alignment at the Winter Solstice, during the period when the circle was under construction, the sun would have set behind Slieve Snaght. This has led archaeologists to suggest that one possible reason for constructing the circle was to pinpoint the time of the shortest day. This would presumably have taken our ancient ancestors some time to work out, requiring clear days in order to observe the path of the sun. The weather must have been better on Bronze Age Islay, as every time I go up to the circle to look there is a band of cloud obscuring Northern Ireland!
It has been proposed that the stones at Ballinaby mark a lunar phenomenon rather than a solar phenomenon. Two stones remain but Pennant has suggested that there were originally three stones. There is no trace of the third stone and the second appears to have been broken, the tallest remaining stone is almost five metres in height. As well as the cycles of the moon that we are familiar with, it also goes through a cycle of rising positions on the horizon which repeats itself every 19 years roughly speaking, the northerly and southerly extremes of this cycle are known as major lunar standstills. Two possible alignments have been suggested for the stones at Ballinaby. The flat face of the tallest stone aligns with a coastal promontory to the north-west. The full moon sets behind this promontory at its extreme northerly setting point.
The second alignment involves both the remaining stones. Standing at the broken stone and assuming a line to the tallest stone and on to the horizon marks the position of the setting of the full moon at its southerly extreme. We have no dates for the erection of the stones at Ballinaby. It would be interesting to know if the third stone, commented on in the mid 1700s by Thomas Pennant, confirmed this alignment.
At Finlaggan, near the Visitor's Centre, there is a standing stone around two metres in height. In 1994 excavation and geophysical work was carried out in this area and it appears that the stone does not stand in isolation but may be part of a larger monument. Alignments have been suggested with the sun, moon and stars in the form of the constellation of Orion rising from behind the stone.
Of course, some people think that this is mainly nonsense! Most archaeologists take the view that these sites probably had more than one function for the people who created them and were not solely used for astronomical purposes. It must be remembered that stones may have disappeared and shifted position over the years and what we are extrapolating from may only be a small part of the ritual landscape that our ancestors were utilising. I would recommend that you keep an open mind when visiting sites where astronomical connections have been proposed and make up your own mind but please do go and see them if you can because they are all in great locations.
Caldwell, D.H. (2001) Islay, Jura and Colonsay A Historical Guide. Birlinn Limited.
MacKie, E W (1974) 'Cultoon stone circle', Discovery and Excavation in Scotland, 1974, 10-11
Pollock, R. (2008) www.stonesofwonder.com
Powell, M.J. (1995) 'The Astronomical Potential of The Paps of Jura from a Prehistoric Site on Islay, Scotland' website
Ruggles, C. (1999) Astronomy in Prehistoric Britain and Ireland. Yale University Press