 A series of stones, located to the west of the arrangement's western apex, mark the positions of the setting sun at the equinoxes and solstices.A survey study shows that these alignments are accurate to within a few degrees.Additionally, the straight sides of the arrangement, which diverge from its eastern apex, also indicate the setting position of the sun at the solstices to within a few degrees and at the equinoxes the sun sets over the three prominent stones at the apex.