The sky-line from the centre of the circle was defined by the site of the vanished barrow, angular elevation 20′, and it is highly probable that the function of the barrow when built was to provide a new sight-line when the star-rise place was no longer exactly pointed out by the piper line.

With these data the star in question was Capella, dec. 29° 58′ N., heralding the February sunrise, 2160 B.C.

I next come to the famous menhir Goon-Rith. The conditions are as follows:—from the circle Az. S. 81° 35′ W. Altitude of sky-line 34′.

Concerning this alignment from the circle, it may be stated that it cuts across many ancient stones, including one resembling a rock basin or laver, and another either a holed stone or the socket of a stone cross. I suspect also the presence in old days of a holy well attached to the circle, for there is a pool of water in a depression which is shown in the 25-inch map.

I regard it as quite possible that we are here in presence of the remains of a cursus, an old via sacra, for processions between the circle and the monolith.

I have not been able to find any astronomical use for this stone from the circle or from the site of the old one, but if we suppose it to have been used like the Barnstone at Stenness for observations over the circle its object at once becomes obvious.

From the azimuth given, the declination of the star was 5° 24′ N. Now this was the position of the Pleiades B.C. 1960, when they would have warned the rising of the May sun.

So that it is possible that the erection of the Pipers and of Goon-Rith took place at about the same time, and represent the first operations.

The next alignment has an azimuth of S. 69° W. from the circle; it would be the same within a degree from the site of the one which has disappeared; altitude of sky-line 32′; this line is to a stone cross on rising ground,[116] doubtless a re-dressing of an old menhir, and on the line nearer the circle are the remains of a barrow.

With these data the star in question was Antares, dec. S. 13° 18′, heralding the May sunrise 1310 B.C.