The constellation Draco has two eyes represented by the stars Eltanin and Rastaban. Owing to precession these eyes have been travelling south on the celestial sphere for the past twelve thousand years. They are now reaching their southerly extreme and will then start travelling north again.
Eltanin has reached its southerly extreme and now passes vertically over Barbury Castle (the earthwork just north of Avebury).
The star Eltanin passes overhead 4 arc minutes north of Silbury Hill.
The star Rastaban passes overhead 4 are minutes north of the summit of Mt Brandon in Ireland.
The third bright star in the head of Draco passes 4 arc minutes north of a perfect alignment with the summit of Ben Nevis (Britain’s highest point).
These three alignments are near simultaneous. The illustration shows the stars of the Dragon’s head (the two eyes are to the south) as they pass over the British Isles in the present day, every day.
Eltanin, the brightest star in Draco, currently passes over the Avebury area at midnight on the summer solstices.
The Avebury Henge (called “The Dragon Ring” in some folklore) lies precisely on the line of latitude one seventh of the earth’s circumference from the North Pole.
The present star epoch includes the ‘lowest’ or most southerly extreme of the brightest celestial eye of the Dragon, Eltanin.
The ‘vertical’ alignment of Avebury Henge and the Dragon’s eye (if such a lower culmination alignment was intended) is accurate to about one part in 760 parts of the arc.
The Saxon font in Avebury church shows a bishop poking the eye of a dragon with a stick or crosier.