In the previous article, the 7,500 foot-long Erdevan alignments were seen to have been a long count of the Saros period of 19 eclipse years versus the distance to Mane Groh dolmen of 19 solar years, this probably conceptualised as an 18-19-6 near-Pythagorean triangle, whose inner angle is the bearing from east of Mané Groh. However, the path directly east caused the actual alignments, counting the Saros, to veer south to miss the hill of Mané Bras.
It has been remarked that the form of the northern alignments of Edeven were similar to those starting at Le Menec's egg-shaped stone circle 4.25 miles away, at a bearing 45 degrees southeast. Whilst huge gaps have been caused in those of Edeven by agriculture, the iconic Le Menec alignments seem to have fared better than the alignments of Kermario, Kerlescan and Petit Menec which follow it east, these being known as the Carnac Alignments above the town of that name.
One similarity between alignments is the idea of starting and terminating them with ancillary structures such as cromlechs (stone kerb monuments), such as the Le Menec egg and, despite road incursion, a 3-4-5 structure similar to Crucuno, aligned to the midsummer sunset by a length 235 feet long. This is the number of lunar months in the 19 year Metonic period and is factored 5 times 47. Another similarity may be seen in Cambray's 1805 drawing of these Kerzerho alignments, at the head of ten stone rows marching east (figure 1).
Figure 1 Cambrey's 1805 engraving of Kerzerho's western extremity of the Erdeven alignments showing the stone rows now lost to agriculture.
In these northern alignments, the bearing of the 18-19-6 triangle has the same angle to the south-east as the Carnac alignments have to north-east because both recorded the same relationship between the solar and eclipse years, whilst having a different focus on eclipses and the moon's nodal period, respectively.
As previously stated, the northern project was studying the Metonic period as consisting of five of the 47-month long Octon eclipse period of four eclipse years, and in 5 of these 235 lunar months equal the 19 solar years of the Metonic.
In contrast, the Carnac alignments over 4 miles south-east were initially studying the movement of the deviation of the moon from the ecliptic, by continuously observing the horizon events of the moon. Normally, only the maximum and minimum standstill of the moon can be deduced as alignments of interest for megalithic astronomers and, at Carnac, these alignments were easy, being very closely the alignment of the diagonals of single and double square respectively. But it is the triple square whose diagonal's length, relative to its base, gives the length of the solar year relative to the eclipse year. This interplay between lunar alignments and Carnac's natural counting geometry can be seen in figure 2.
Figure 2 Thom's survey of Le Menec Alignments and the interplay of triple, double and single square diagonals relative to east
All of the indications are that the northern alignments preceded the southern (Carnac) alignments in that; having established the best eclipse period of all (the Saros), the next objective would be to study the 18.618 years over which the range of moonrises and moonsets (to east and west) have a variable angular range over an 18.618 year cycle, the minimum being the least angle (26.565 degrees) from east (or west in setting) and the maximum over the its greatest angle (~45 degrees) from east (or west in setting)—a full right angle between northerly and southerly.
Another interesting comparison between Kerzerho and Le Menec is to place Thom's survey of the Le Menec over the Google Earth image so as to make a direct visual comparison of unsuspected similarities.
Figure 3 Overlay of Thom's survey of Le Menec upon Google Earth image of Kerzerho showing the Metonic month count at 36.8 degrees, 18.4 degree bearing to Mane Groh and similar offsetting of initial menhirs starting the alignment according to the angle of a double squares diagonal (26.565 degrees east of north) .
The staggering at onset of Erdeven's northern-most rows is very similar to those at Le Menec, noting that it was only Le Menec's first rows that followed Thom's abstract line, this then passing along the cromlech's informing hypotenuse (of a Pythagorean triangle 3-4-5). Thom found for the angle of stagger to be that of a 1-2-√5 hypotenuse (60o relative to north) as appears the case at Erdeven also. The white line, marked by its 18.4 degree angle from east, heading to the tumulus/dolmen Er Groh, would instead point directly east if Figure 3 has been tilted, instead, for Le Menec; showing that these alignments are somewhat symmetrical mirrors of one another. The 36.8 degree line to midsummer sunset would then become the Le Menec's egg's shorter axis pointing to the midsummer sunrise.
This sort of comparison draws attention to the eastern hypotenuse of where the egg would be, in the back garden of the house. One stone apparently exists on that hypotentuse (and starting line of alignment) in the position that would terminate row 10 of Le Menec, but at Kerzerho also would terminate a row, as per figure 4.
This demonstrates that more than passing comparison of the northern and southern alignments may reveal mysterious similarities pointing to new ideas as to the purposes of the two monuments.