The Discovery of a Soli-Lunar Calendar Device at Le Manio

by Robin Heath

In 2009 I returned to Plouharnel, again for the Solstice Festival, and undertook my own research both before and after the four day event. Howard Crowhurst had undertaken a great deal of theodolite and tape work at a well known site called Le Manio. This collection of surviving monuments forms an exceptionally rich group of astronomical alignments which together carry enormous ritual significance in that these sites hold information about human conception, the gestation period and ritual use of geometry and metrology. Howard understands the site to the point where his three hour workshop covered much of this material, and the implications of it were clearly understood by non-specialists. Those readers who have the chance to attend the Festival, and who speak either English or French, should regard this experience as a megalithic ‘must’. Howard is an exceptionally good communicator of what are often seen as difficult areas of megalithic research, and he is astonishingly good at passing these ideas on to his audience with a great deal of clarity, enthusiasm and humour.
It was during Howard’s seminar/workshop that he invited me to set up his theodolite within the Le Manio Quadrilateral, a curious site near the 6.5 metre high ‘Giant of Le Manio’. This done, I noticed something I had been searching for for twenty years. Read on…!

Day-inch counting at the Manio Quadrilateral

It is 10 years since my brother and I surveyed this remarkable monument which demonstrates what megalithic astronomy was capable of around 4000 BC, near Carnac. The Quadrilateral is the earliest clear demonstration of day-inch counting of the solar year, and lunar year of 12 lunar months, both over three years. The lunar count was 1063.125 day-inches long and the solar 1095.75 day-inches, leaving a difference of 32.625 day-inches. This length was probably the origin of a number of later megalithic yards, which had different uses.

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Sacred Number and the Lords of Time

Back Cover


“Heath has done a superb job of collating his own work on the subject of megaliths with the objective views of many other researchers in the field. I therefore do not merely recommend reading this book but can state unequivocally it is a must read.”
–John Neal, British metrologist and researcher and author of Measuring the Megaliths and The Structure of Metrology

“In Sacred Number and the Lords of Time we have an important explanation of how megalithic science was developed. This book is a long-overdue wakeup call to a modern culture that has abandoned this fully developed and astonishingly rich prehistoric model of the physical world. The truth is now out.”
–Robin Heath, coauthor of The Lost Science of Measuring the Earth and author of Sun, Moon and Earth

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paper: The Origins of Day-Inch Counting

This paper presents the theory that in the Megalithic period, around 4500-4000 BCE, astronomical time periods were counted as one day to one inch to form primitive metrological lengths that could then be compared, to reveal the fundamental ratios between the solar year, lunar year, and lunar month and hence define a solar-lunar calendar. The means for comparison used was to place lengths as the longer sides of right angled triangles, leading to a unique slope angle. Our March 2010 survey of Le Manio supports this theory.

Sacred Geometry: Language of the Angels

Pages: 288
Book Size: 8 x 10
ISBN-13: 9781644111185
Imprint: Inner Traditions
On Sale Date: January 5, 2021
Format: Hardcover Book
Illustrations: Full-color throughout

For further details of the book look at the growing Publisher pages for it at Inner Traditions.

Silbury Hill: Metrological Key to the Model of the Earth between Stonehenge & Avebury

Archived: 11 August 2012

The exact location of Silbury Hill is as mysterious as the purpose of the Hill itself, a thirty degree cone, only recently with a flat top, overlooking Avebury and the surrounding hills. The Hill figures in John Michell’s model of the Earth between Stonehenge and Avebury in which one quarter of a degree of latitude, between the two henges, appears to have been measured by a type of Persian foot so as to make the number of feet, in between, equal numerically to that required to perfectly model the Earth using 864:866:867 double triangle.

The double triangle model of the size of the Earth between Stonehenge and Avebury

There are 86400 Persian feet of 1.056 feet (south to north) between Stonehenge and Avebury Ridgeway enabling the Avebury henge to be 86600 of these Persian feet from Stonehenge, then to represent the Mean Earth radius (see Initial Article – missing link). The Avebury henge appears to have been specifically tied to the distinct Latitude of 360/7 degrees.

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