Stonehenge Solved Its Three Observatories, Who built them, How and Why

At this juncture note that it is still the aim-design which is under consideration. In combination the spars, which could only reach angles of 30-40 degrees, could sweep the entire horizon, except for a sector to northwest. This exception was because at station 123, the low elevation spar was foregone in favour of a secondary entrance between two groups of high elevation spars, Fig 15. The horizontal swing of each spar was limited to the positions where it struck its uprights. But this was enough to enable collective coverage of what would otherwise be gaps created by the main entrance, and the trios of hoist-assisted high elevation spars. The two entrances were essential because elsewhere the circle was an almost impenetrable cat's cradle of lines with maintenance, and perhaps re-sets going on, disturbance being unwelcome. There is no apparent reason why the two entrances were positioned so close together circumferentially, but as we will see, the spacing replicates a similar one at Woodhenge (i). Woodhenge was an experimental prototype for the Stone henge. Certainly, two entrances suggest a need to avoid congestion at all times.

In contrast to the degree of horizontal flexibility of low level spar settings, the trios of hoist-assisted ones had limited scope. This was because in addition to the constraining positioning of the masts relative to the circle, a hoist line had to be aligned immediately above its spar, otherwise the latter would tend to instability. The runs of the hoists at the southwest mast were more predictable than those of the others, consequently it had only three bollards, one for each hoist. The other masts had four, thereby offering a choice of run.

An intriguing aspect concerns the differing heights of the masts: the southwest mast is tallest, the ones each side of it somewhat shorter, the two beyond these lower still. The consequence was while the spars of all five could reach the same maximum angle, which occurred if and when they fouled their station beams, their lowest possible angles differed. The three southwest station hoists could achieve a lowest angle of elevation equal to the maximum angle of the low level spars each side of them; this before they sagged on to the station beams. However, at the other masts the hoists draped on the station beams before the angles of their spars matched those of the adjacent lower elevation spars.

There were no masts between north and east. The limited ranges of movement at each hoist-assisted station resulted in observational, or sighting, widows in the dome of the sky, Fig 16. But to them must be added the observational capability of the unassisted, low level spars, all round the horizon except for the gap on the northwest. To southwest there was a continuous vertical panel of capability from the horizon up to the point where the three spars struck their beams. The question now is what was being observed?