Editor Mike Pitts
In His best-selling and controversial 1965 book Stonehenge Decoded, Gerald Harkins claimed the monument was a 'brilliantly conceived astronomical observatory'. He was to talk at the Fourth Conference on the Inspiration of Astronomical Phenomena, held in Oxford in August 2003, but died in May, aged 75. With archaeologist Vance Tiede, Hawkins addresses Stonehenge for the last time
Why was Stonehenge built? How did it function? British archaeologists have been reluctant to say. New analysis supports the astronomical interpretation first published in Nature in 1963.
At that time, many archaeologists dismissed the theory because of the poor site plan. In 1978 Richard Atkinson published a precise survey of the Station Stone rectangle, the Heelstone and the Avenue axis, ‘because the possible astronomical significance of Stonehenge has made it desirable to make new measurements of its features.’ Re-calculated alignment values confirm that not only did the centre of the sun’s disc line up with the axis exactly at midsummer sunrise and closely at midwinter sunset, but that the centre of the High Moon lined up with the long sides of the Station Stone rectangle at midwinter moonset. The short sides of the rectangle, being parallel to the axis, also point to the midsummer and midwinter sun. The displacements have decreased to less than 0.5°, the width of the lunar and solar discs – less than the width of the little finger held at arm’s length.
Atkinson himself asked: ‘What is the accuracy of the alignments? ... You have to go to the site and measure things precisely’. The final result is as much as one could expect of observations with the unaided eye. This survey was perhaps the most important contribution that Atkinson made to Stonehenge astronomy.
Around 50 BC the Sicilian historian Diodorus described a temple often identified as Stonehenge:
… Hecateus [c 350 BC] and certain others say that in the region beyond the land of the Celts [Gaul] there lies in the ocean an island no smaller than Sicily. This island… is inhabited by the Hyperboreans… there is also on the island a magnificent sacred precinct of Apollo and a notable temple adorned with many votive offerings and spherical in shape. They also say how the moon viewed from this island appears to be but a little distance from the earth… the god visits the island every 19 years, the period in which the return of the stars [astron] to the same place in the heavens is accomplished; and for this reason the 19-year period is called by the Greeks the year of Meton (Diodorus Siculus, II).
Archaeologists now regard the 56 Aubrey Holes as having held large posts. But why not 57, a multiple of the 19-year period of the Metonic cycle?
The cycle says that if there is a full moon on 21 June, the moon again will be full on 21 June 19 years later, but at a different position on the horizon. If the full moon starts over the Heelstone, for example, it will slowly slip away each 19 year interval. On the other hand, if you count 19, 18 and 19 years (a total of 56), it will stay completely on the stone throughout many cycles. It would seem that the Stonehengers had knowledge of both: there are 19 stones in the bluestone horseshoe and there are 56 holes in the Aubrey circle.
It is not the return of ‘stars’ alone to the same place in the heavens that is marked by the horizon alignments at Stonehenge, but rather of the luminous bodies (astron), that is sun, moon and stars. We interpret Diodorus’ words to mean that Stonehenge records the turning points of the midsummer sun and midwinter moon with the seasonal zodiac stars, when all these luminous bodies return to the same place in the Year of the High Moon every 19+18+19 years.
The Roman writer Plutarch (2nd Century AD) provides the evidence to link 56 with eclipses, supported indirectly by the ancient myths of cosmic struggles between light and darkness, Greek (Typhon vs Zeus) and Egyptian (Set vs Horus and Osiris):
… [T]he 56-sided polygon is said to belong to Typhon, as Eudoxus [Greek astronomer c 370 BC] has reported… There are some who give the name Typhon to the shadow of the earth, into which they believe the moon falls and so suffers eclipse… which the sun remedies by instantly shining back upon the moon when it has escaped the earth’s shadow (Plutarch, De Iside et Osiride 30,44,55).
The movement of the moon has occupied the lives of many, many astronomers, and there are hundreds of terms to describe it. That the moon undergoes this movement to higher declinations, higher and higher in the sky, and then becomes lower and lower, has come out of the Stonehenge study. In certain places, such as Northern Ireland, the moon would disappear. In other higher latitudes, it would become circumpolar, never setting – the land of the midnight moon, one could say. The 56-year cycle which controls it was not really understood or mentioned by astronomers. It is something that has come from the past to us – ancient knowledge transferred in a set of alignments.
There seems to be no practical value in what was going on at Stonehenge. One does not need Stonehenge to know when to plant seeds or when to breed cattle. Perhaps part of the purpose might have been for the handmaiden of astronomy—astrology.
Astronomy has grown out of astrology, though we may hate to face that fact. Uncanny powers were placed on celestial objects, and predictions were made which directly related, whether they came true or not, to human lives and events. There may have been some prognostication at Stonehenge.
We once said to a class of gifted students that perhaps the people at Stonehenge were able to say every 8 or 9 years, when the moon rose over the Heelstone, that it was in danger of being eclipsed. And one very, very bright young man said, ‘Why not the other way around? For 8 or 9 years, the people there could say that it was a clear year, the moon is safe. They would win out for 8 or 9 years. Even by saying “There is danger now of the moon disappearing and we must make preparations”, they could have won out, for the eclipse might not have been observable in southern England’.
The sun could have been the god of life and the moon the god of death. Stonehenge might have been connected with the spirits, with the afterlife, birth and all the things that made life and existence important for people in Neolithic times.
In light of Atkinson’s Stonehenge survey and the ancient accounts cited above, we conclude that the inspiration of astronomical phenomena sparked Neolithic architects’ celestial vision on Salisbury Plain. What better way to recreate their lost vision than with a digital ‘Virtual Stonehenge’ under a ‘Virtual Neolithic Sky’ in the new Stonehenge visitor centre? The astronomy has spoken and the numbers are quite clear.
CBA web:Jan/Feb 2005