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.

Harlech stone row, Gwynedd, North Wales.

Harlech Stone Row OS.
This stone row stands on a commanding position overlooking Porth Madog Bay and the Lleyn Peninsula to the West and the mountainous high ground of the Harlech Dome to the East.

On the high ridge above Harlech Castle stands a stone row which stretches for nearly 1.5 kilometres in a north/south direction.

As with the Llananno Complex in Mid Wales the 9 Standing Stones of the Harlech Stone Rows occupies the central spine of three North/South intervisible ridges here offering another superb situation for Megalithic Positional Astronomy.

S2, Harlech to Rhinog Fawr.

One Megalithic Calendar alignment for two dates has been confirmed by photography and digital extrapolation. Stone S2 Harlech to Rhinog Fawr's north face presents the declinations for Calendar Intervals 10 & 16.





The Rhinogs east of Harlech Stone Row.

Harlech Dome.
To the east the prominent heights of the Rhinog mountains dominate the horizon. From north to south they express the entire eastern range of the Ecliptic, Summer Solstice to Winter Solstice, as seen from this stance at S2.

Rhinog Fawr north flank: an Angle of Obliquity to the Ecliptic bank.

Obliquity on Rhinog Fawr from Harlech S2.
The top of this carefully dressed menhir mirrors the slope of the prominent mountain flank of Rhinog Fawr the tallest peak of the Harlech Dome massif. This stone is some 2 metres (6'6") tall. An adult at about 5 foot 6 inches tall, (1.5 metres), standing behind and higher on the rising ground, looking over the menhir, will find the angled top will align precisely with the slope of the northern flank of Rhinog Fawr, the tallest height of the Harlech Dome massif.
From this procession of photographs of Jupiter rising on the morning of 8th November 2017 we can see how closely this profiled menhir mirrors the northern slope of Rhinog Fawr and the Angle of Obliquityto the Ecliptic.
This backsights S2, offers one of the clearest examples of a profiled stone giving an indication of which direction to look to find Megalithic Calendar Foresights. The dressed top of the stone presents an obvious profile not only of the slope of the indicated mountain, Rhinog Fawr, but also the Angle of Obliquity to the Ecliptic for this Latitude, This position, marked by the menhir, has been carefully located. It is the observing stance from where the Sun will rise at the foot of Rhinog Fawr north slope when at the declination of Megalithic Calendar Intervals nos. 10 & 16 with declination -8° 27.6'

Extrapolating from Jupiter and the rising Moon on Rhinog Fawr north slope.

To date an opportunity to photograph this alignment in astronomical action, i.e. with the Sun's semi-diameter sliding up the slope of Rhinog Fawr, has not yet been acquired. However weather opportunites to shoot sets of images of the more frequent risings of the Moon and planet Jupiter near to the foresight have been secured on the evenings of the 29th and 30th of April, 2018 and the 8th of November 2017.

Two sets of Lunar rising paths were captured on the evenings of the 29th and 30th April 2018.

The precise declinations of these two rising tracks were read from the USNO data tables of the Geocentric Positions of Major Solar System Objects and Bright Stars.
From these two declination tracks an accurate scale on the Rhinog horizon was derived and a precise extrapolation to the declination of the Sun at Calendar Intervals 10 & 16 was made by digital draughting. The result is shown with this survey.
Survey no7 S2 Harlech to Rhinog Fawr



Survey no6 S2 Harlech>
	<div class=From the stance S2 the Sun, at the necessary declination , -8° 27.6', will be seen to glide up the north flank of Rhinog Fawr, at hull down, on Calendar Intervals 10 & 16 of the Megalithic Calendar. These dates are, in the Gregorian Calendar, 27 Feb.& 15 Oct.






S2 Harlech to Rhinog Fawr north slope is a Megalithic Calendar alignment.

This alignment presents the Angle of Obliquity to the Ecliptic at the declination for Calendar Intervals nos. 10 & 16.
The menhir S2, Harlech Stone Row, is positioned on the precise place where an obsever must stand to see the Sun ride up the length of the north slope of Rhinog Fawr at sunrise on Calendar Intervals (CIs)10 & 16.
The Gregorian dates today would be sunrises on 27th February and 15th October.