Two pairs of trilithons are set using circles identical in size to that of the sarsen circle.

Centre-points and radius length are essential information required when setting out arcs. Stonehenge’s designer made a plan. The builders used the plan to physically locate the trilithon arcs.

The location of the red-circle centre-points is extremely significant. The relationship of these points to the Sarsen and Blue-stone circles reveals the unit of measurement used to set out Stonehenge, … and why it was so important.

The arcs cut the ‘solstice axis’ on the Blue-stone circle at C, and Sarsen circle at A. Within the arcs are two perfect or equilateral triangles, (FFA and FFC)

On the axis are seven fixed points:

four are where the axis intersects the sarsen (A,B) and blue-stone circles (2 x C) ,

and blue-stone circles , two are the triangle centres (2 x D) ,

, and Stonehenge’s centre-point, (E).

Below is how Stonehenge was set out prior to being constructed. This original unit of measurement I’ve called a Baunt (Bronze- Age UNiT). 1 baunt is 1.037* metres, about a pace.

*Based on a paper calculation.

An earlier plan, first published 31.12.2015, illustrates how the trilithons were located on the arcs using these 3-baunt marks.

Plans based on a survey by Johnson et al, 2008.