Glossary X
At a lunar backsight where permanent or temporary ancillary extrapolation gear has been set up there should be a length preserved between major stones which is the 4G for this site. This 4G represents, on the ground, the lateral distance an observer must move in order to 'shift' the Moon through the declination range K. K is the change in the Moon´s position during the 24 hours preceding a standstill. At a Major Standstill it is 46.5 arc minutes and at a Minor Standstill 30 arc minutes. See also- K, ANGULAR DISPLACEMENT, EXTRAPOLATION PROCEDURE, LUNAR STANDSTILL.

S1, Llananno to Dick's Seat tumuli group,

High precision Megalithic calendar alignment indicating the rising point of the Sun on two megalithic calendar intermediate dates- CIs 2.5 7.5 which occur in the Gregorian calendar @25th April @18th August. The exact declination of this point is +13° 13.2'.
This group of three impressive tumuli sit astride a local hill lane crossing the top of Rhiw Port here. However the higher ground behind carries the horizon line as viewed from S1, Llananno stone circle.
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S1 to Dick's Seat OS.

As with most of the tumuli groups in Llananno the mounds are arranged on the exact summit of the hill.

The arrangement here, though clearly astronomical does not lend itself to the best observational practice. The tumuli do not break the horizon as the ridge of Kerry Forest behind is several metres higher.
Also the surrounding hills, though more prominent, do not carry tumuli groups. This appears to be because their tops do not coincide with bearings for one or other megalithic calendar division points.

Detailed examination of the Ordnance Survey shows the care the builders took in relating the summit of Rhiw Port with the required astronomy.
Neither of the hill-tops to either side of Dick's Seat have been chosen to carry tumuli. It appears that only summits of hills exactly aligned with calendar interval declinations were deemed appropriate cemetery sites.