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Glog Hill

S1, Llananno to Glog Hill lunar standstill alignment, Mid Powys

S1, a 2 ton block carved as a seat, sits at the center of a ruined stone circle in the parish of Llananno.

W/7.2.1   Glog Hill, Dolfor is perhaps the largest Bronze Age barrow cemetery in Wales. Some nine tumulii are strung along this hill crest. W/7.2.2  Markers for the extremes of Cyclic Perturbation. The moon in it's orbit exhibits a marked 'wobble' with an amplitude of 18 minutes of declination. At a suspected lunar standstill foresight we should expect to see the alignment catering to one or other, (if not both), extremes of this perturbation. Moonrise with declination 29* 12' = (e+i+p) 1800 BC.

Extrapolating from time-lapse photographs taken on the evening of the 18th November 2005 we see that the lower limb of the moon at the Northern Major Standstill in 1800 BC, rising with maximum perturbation, glances up the northern flank of Glog Hill, Dolfor. Tumulii a, b, c and d all lie within 2 arc minutes of declination to the path of the lower limb. W/7.2.3Moonrise with declination 29* 3' = (e+i) 1800 BC. No tumulii lie near either limb when moon rises at mean perturbation, (e+i).

W/7.2.4  Moonrise with declination 28* 54' = (e+i-p).

The lower limb of the moon will depart the horizon from the tumulus f. Although, here, the moon at negative perturbation would rise with two tumulii near the centre point of the disc, tumulii c and d, these would not make the most reliable observation. Reading from the centre is not as certain as leading an upper or lower limb onto a tumulus. However this could serve as a fore-warning and optical check and on the calculations derived from stake-setting positions for upper and lower limbs..

W/7.2.5  It is probable that the principal standstill backsight marker for this lunar observatory is the stone block S2 exactly 223.86 metres,(270 MY), distant to the south. See: S2, Llananno to y Glog. We have seen that this step-aside distance gives an angular displacement on the horizon of precisely one lunar diameter. See: S1 to S2 angular displacement. Hence it will be the upper limb glancing up y Glog's flank. The readings from S1 are to the lower limb of the moon and cannot be considered as reliable as sighting to the upper limb as from S2.

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