Archaeoastronomy and Stonehenge

Stonehenge has an opening in the henge earthwork facing northeast, and suggestions that particular significance was placed by its builders on the solstice and equinox points have followed.

While it is possible that such an alignment could be coincidental, this astronomical orientation had been acknowledged since William Stukeley drew the site and first identified its axis along the midsummer sunrise in 1720.

Stukeley concluded the Stonehenge had been set up "by the use of a magnetic compass to lay out the works, the needle varying so much, at that time, from true north."

He attempted to calculate the change in magnetic variation between the observed and theoretical (ideal) Stonehenge sunrise, which he imagined would relate to the date of construction.

Sir Norman Lockyer proposed a date of 1680 BC based entirely on an incorrect sunrise azimuth for the Avenue, aligning it on a nearby Ordnance Survey trig point, a modern feature.

'Steve' Newham and Sir Fred Hoyle, the famous Cambridge cosmologist, as well as by Alexander Thom, a retired professor of engineering, who had been studying stone circles for more than 20 years.

Their theories have faced criticism in recent decades from Richard J. C. Atkinson and others who have suggested impracticalities in the 'Stone Age calculator' interpretation.

He had studied 165 significant features of the monument and used the computer to check every alignment between them against every rising and setting point for the Sun, Moon, planets, and bright stars in the positions they would have occupied in 1500 BCE.

Atkinson replied with his article "Moonshine on Stonehenge" in Antiquity in 1966, pointing out that some of the pits which Hawkins had used for his sight lines were more likely to have been natural depressions, and that he had allowed a margin of error of up to 2 degrees in his alignments.

He also identified a lunar alignment; the long sides of the rectangle created by the four station stones matched the Moon rise and moonset at the major standstill.

The only megalithic monuments in the British Isles to contain a clear, compelling solar alignment are Maeshowe, which famously faces the winter solstice sunrise.