Note the solstice angle at the Silbury Hill to East Kennet latitudes ranged from 130.72 to 130.71 degrees E of N., correlating the Avebury to Silbury Hill arc and the long barrow arc to 1/10,000 of the solstice angle. Also, winter solstice near Avebury aligns to Mont Blanc; the monument bearings to the mountain range 130.74 to 130.71 degrees. The air temperature variable alters the solstice angle more than this variation.

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