The area
of north east Scotland centred around the city of Aberdeen is notable
for both the large number and architectural consistency of its stone
circles. The most obvious common feature is the presence of a large
recumbent stone which is usually positioned on the south western side
of the circle. This recumbent stone is flanked by two stones set up on
end in the usual manner. These flankers are the tallest stones in the
circle and the other circle stones are graded so that they decrease in
height with increasing distance from the recumbent stone as you move
around the circle so the smallest stones will often be found at the
north east side. The site of the circle was often made level by
building a bank or cutting into the hillside and all the circles
seem to be positioned to provide a clear view of the south western
horizon. The interior of the circle contains a ring cairn with a
central space within which cremated bones were placed. The stones
surrounding the recumbent or often the recumbent itself are frequently
cupmarked. Pieces of quartz were sometimes scattered in front of
the recumbent stone on the inside of the circle.
It is clear that the centrepience of these circles is the
characteristic recumbent stone. Examination of these stones reveals
that great care was taken in their positioning such that the top of the
stone is perfectly horizontal. This was achieved by the inserting
smaller chocking stones underneath the recumbent stone in order to
precisely align it. So why was such considerable effort expended
to get the orientation of the recumbent just right? This question
has caused a great deal of speculation and theorising to have taken
place. Astronomical alignments of recumbent stones were proposed,
usually towards risings and settings of the Sun, the Moon, Venus and
even various stars. However none of these were consistent or
particularly plausible or convincing.
The answer was eventually found by Aubrey Burl (who else?) in
1980. The recumbents and their flankers are aligned on the Moon
but the alignment is more complex than a simple sightline to a
particular rising or setting. The reason for this is that the
behaviour of the Moon in the sky is more complex than that of the Sun.
The Moon does not always rise or set in a particular place but the
points at which it rises or sets fluctuate over an 18 year cycle.
At the lunar maximum the Moon will rise at the south southeast
and set at the south southwest. For the next nine years the rising and
setting points will fan out towards the north meaning that the Moon
will spend progressively longer in the sky between risings and
settings. After nine years the lunar minimum is reached and the rising
and setting points will begin to close in again until nine more years
later the lunar maximum is reached.
Nearly all the recumbent stones are aligned between the points of
maximum moonrise and maximum moonset. The maximum Moon would not have
risen high in the sky and would have been framed by the recumbent and
flankers when viewed from the circle, partularly during the summer
months. Different circles are aligned towards different aspects
of the maximum Moon, either its rising, setting (most frequently) or
culmination. There are a few exceptions though such as the circles at
Sunhoney and Midmar Kirk. Here the maximum Moon is obscured by hills so
the circle builders had to align their recumbent on the minor moonset
instead.
All this points to the Moon having a major significance for the
circle builders. By night the quartz fragments scattered around the
recumbent would have reflected the light of the full Moon as it passed
over the recumbent at its maximum point. The cupmarks (representations
of the Moon?) could also have been picked out in the moonlight.
The presence of cremated bone (as opposed to full burials)
suggests these were left as offerings. Did a lunar cult exist in
Aberdeenshire 4000 years ago?