Soil resistance work (“geophys”), by archaeologists from the University of Leicester, of the land inside the southern stone circle of Avebury Henge, has revealed more about the Obelisk and lines of standing stones, which appear to have formed a near-square rectangle. Information can be hard to obtain when work is yet to be published but a press release to the Guardian and others many months ago (December 27th 2019) enabled figures from a media set to be viewed with public access. This has enabled me to so some site interpretation, using the (as-yet damned) numerical technique called ancient metrologyThe application of units of length to problems of measurement, design, comparison or calculation.. My results are fascinating and build upon the megalithic use of counting time as length to track important time-cycles such as the Nodal PeriodUsually referring to the backwards motion of the lunar orbit's nodes over 6800 days (18.618 years), leading to eclipse cycles like the Saros. of 6800 days, between lunar maxima and minima, and the MetonicGreek: The continuous 19 year recurrence of the moon's phase and location amongst the stars. period of both 19 years and 235 lunar months, within which all of the varied orientations of Sun Moon and Sky are recycled.

Whether you know a lot or a little about the world-class Averbury henge 17.28 miles north of Stonehenge, its curious geometry of 99 +/- 1 standing stones and double stone circle within, you will enjoy looking at this page where a history of its mapping is visually summarised by https://megalithicmaps.com/ whose new Archaeological Map of Avebury integrates many recent results with those of previous surveys.

A section of Thomas Melrose’s map was scanned to allow explanation of what was originally illustrated using the Leicester figure 3 (which only news media can publish). By the way, the Melrose map is to be recommended for research and informed visiting of Avebury, my brother having reviewed it at robinheath.info.

I had originally used the Melrose map to look for a particular length found significant at ClavaA type of circular Bronze Age cairn, with a circular chamber, named after the group of three at Balnuaran of Clava, east of Inverness in Scotland. Cairns, namely 204 feet or half of that 102 feet using calipers, and the latter was found between the north western stone and southwestern stone of what is being called the Avebury Square by the Leicestershire archaeologists. This 102 foot length is also 37.5 megalithic yards (MY) of 2.72 feet, the figure arrived by Alexander ThomScottish engineer 1894-1985. Discovered, through surveying, that Britain's megalithic circles expressed astronomy using exact measures, geometrical forms and, where possible, whole numbers. during his surveys of stones circles and other geometries as a likely length employed by the megalithic astronomers. This is also 15 megalithic rods of 6.8 feet. Recent research has discovered that an ancient Middle Eastern “finger” called a shu.si (3/100 feet) divided into 102 feet was 3400 shu-si which, as days, would be half the length of the Nodal period of 18.617 years (6800 days). The shu.si is normally only associated with the Assyrian foot (0.9 feet = 30 shu-si) and double foot (1.8 feet = 60 shu-si), then facilitating the sexagesimal (base-60) arithmetic of the Mesopotamians starting with Sumeria.

A shu-si is 0.36 inches, just over one third. There are 33This is the number of years for an exact number of 12053 days. This period can be measured using the equinoctal sun and it has come to be known as the lifetime of semi-divine Solar Heroes such as Jesus and Mithras. This period relates geometrically to the 18.618 years of the moon's nodal period. and 1/3rd shu-si in a foot and a significant number of other historical feet are rational to it. Called a “finger” because it is a metrological digit, counting 3400 in inches or feet would be very large and so with large counts, a shorter length was achieved by shrinking the larger length through judicious use of natural geometrical mechanisms. That is to say, the shu-si was probably a “child” of the Nodal period and its counting, in days, during the megalithic period. 6800 feet is evidently one thousand times bigger than the megalithic rod of 6.8 feet.

One quarter of a latitudinal degree south is the Stonehenge Aubrey Circle, whose diameter was 3400 inches, capable of being used to count half the Nodal cycle (3400 days) between lunar maximum and minimum, and then reverse so as to count from minimum to maximum (6800 days), using one inch to count each day. The shu.si, at 0.36 inches, when used for the same count of 3400 days would be 102 feet long (3400 shu.si) which is 34 yards since a yard is 100 shu.si long.

Looking for 102 feet may seem to be looking for an answer and finding it except that, I did very little looking on the Melrose map before finding this (lucky perhaps) but then realised that the Metonic period of 235 lunar months, 19 solar years (6939.7 days) can be seen as the two side lengths of a rectangle which fits well the proposed “square” around the Obelisk. 6939.7 days minus 3400 days equals 3539 days which in shu.si is 106.2 feet, as shown.

It seems the time-counting astronomers of the megalithic had noticed the proximity of half the Nodal cycle (3400 days) to half the Metonic period (3469.8 days) so as to form a near-square, in which the longer dimension was the difference between the Metonic and half Nodal periods. The lengths involved might have been symbolically rather than for an actual practical count, using a very small unit of length per day.