Since the Nebra Sky Disk (also known as the Nebra Sun Disk) of Germany emerged into public knowledge in about the year 2000, archaeologists and astronomers have put forward their theories about how it worked and what it meant to the ancient society that fabricated it.

I have assessed it from the standpoint of the scientific knowledge that was encoded into ancient European megalithic sites or early edifices, such as those of the Giza Plateau, and so will now give an account of how I, personally, would have used this artefact as a memory device, based upon easily decipherable, ancient mathematical methodologies.

The Nebra Sky Disk of Germany, recovered from a cache of illegally acquired artefacts in the possession of an antiquities dealer in 1999. The dimensions of the Nebra disk tell us how it functioned as a memory device for recalling principles of navigation and the lunisolar calendar system. Similar mathematical systems of calibration are built into the Ring of Brodgar in Scotland or the Southern Circle at Avebury Henge*, etc. The Nebra disk is thought to have been fabricated 3600-years ago.

The strange count of holes around the edges of the Nebra Sky Disk seems to cause consternation and difficulty for some analysts, working on deciphering the attributes of the disk. To the left is seen one depiction that puts the count of calibration holes at 40, whereas the true count appears to be, quite definitely, 39. To bring the count up to 40-holes, the illustrator crams an extra hole into a damaged portion of the disk. However, an overall comparison of the regular spacing of the holes elsewhere around the circumference indicates that there was only one calibration hole in this damaged section and not two (as shown in the photograph to the left).


The reason for the 39 calibration holes is easily found in analysing the diameter of the disk, which is exactly 1-Greek foot or 12.6 inches (32 cm = 12.6 inches).

Many individuals studying ancient metrology will now accept that the increment known as the British standard inch is, in fact, a very old unit of measurement. It is at the basis of all of the cubits used by the various, much mobilised and migrating cousin European nations of remote antiquity, occupying the countries encircling the Mediterranean, inhabiting central Europe and the British Isles or other areas like Northern India, as well as North and South America.

A Greek foot (of which there were several types, depending on the calculation being undertaken) was simply one half of an Assyrian Cubit (25.2-niches) and, in reality, the measurement wasn't necessarily Greek at all, but had been used by earlier nations and passed to the Greeks. One Greek foot of 12.6-inches (twelve and three fifths inches) is, simply, one tenth of a Hebrew Reed @ 10.5 feet. The Great Pyramid of the Giza Plateau (756 British Standard feet long per side in design length) is 720 Greek feet. Alternatively, The Khafre Pyramid of the Giza Plateau (Egypt's Pyramid of the Moon) is 15/16ths the length of the Great Pyramid @ 708.75 British Standard feet. That equates to 675 Greek feet of 12.6 inches.

In order to understand the workings of memory device artefacts such as the Bush Barrow lozenge, the Clandon Barrow Lozenge (English), the Calendar of Coligny (French) or the Sky Disk of Nebra (German), one has to put all preconceived notions or prejudices aside concerning early scientific accomplishment. One has to set aside all imposed limitations that we have traditionally heaped upon our early forebears and let the artefacts that they fabricated or ancient coded edifices that they built speak for themselves.

The Nebra Sky Disk had two major functions as per it's circumference codes and these related to (1) navigation and (2) to the lunisolar, Sabbatical calendar system

So: Using PI @ 22/7 (3.142857143) the disk's diameter of 12.6-inches expands to a circumference of 39.6-inches (39 & 3/5ths). By this rendition of PI the equatorial size of the Earth and principles of navigation were kept at the forefront of memory and the mathematical methods employed for positional plotting in navigation could be taught to initiates by rote and repetition.

Also: Using PI @ 25/8 (3.125) the disk's diameter of 12.6-inches expands to a circumference of 39.375-inches (39 & 3/8ths). By this rendition of PI the principles of a fully working lunisolar calendar could be taught, such that calculating either solar or lunar positions at any point within the calendar cycles could be done with ease and precision.

Even with theorising that a total of "40" holes could have been present upon the formerly undamaged disk, the use of various common renditions of PI, to turn the disk's diameter into a circumference, still produce values under "40" to describe the disk's intended calibration.


To understand this values one has to look at two navigational methods encoded into the Great Pyramid of Egypt, one based upon numbers divisible by either 6 or 7 simultaneously and another divisible by the number 11

The number system divisible by 6 & 7 became the basis of the Greek and Hebrew navigational systems, composed of a Greek Mile of 5250 feet, a Stadia or Stadium of 630 feet, a short Stadia of 525 feet, a Reed of 10.5 feet and a Greek foot of 12.6 inches. There were also other related measurements in this family of increments, but these listed represented the main lengths.

The Great Pyramid was 756 British Standard feet per side or 3024 feet for one circumnavigation. Two circuits of the Great Pyramid (6048 feet) represented 1-minute of arc for the equatorial circumference of the Earth under this system. In other words, 1-second of arc was 100.8 feet (96 Greek feet); 1-minute of arc @ 6048 feet was 9.6 Greek Stadia of 630 feet and one degree of arc for the world was 362880 feet or 576 stadia. Under this navigational calibration the entire equatorial circumference @ 130636800 feet was 24883.2 Greek miles or 12 X 12 X 12 X 12 X 1.2 Greek miles.

Whereas the Greek mile of 5250 feet and its associated increments survived in the Mediterranean, the British mile of 5280 feet survived as the mainstay of much of the ancient British and Continental European navigation. This was based upon an "11" series or family of numbers.

It is this "11" series system that is incorporated into the circumference of the Nebra Sky Disk

The increments of length under this system were, in British Standard feet:

League (16500 feet), Mile (5280 feet), Furlong or Furrowlong (660 feet), Chain (66 feet), Rod or Perch (16.5 feet), Fathom (5.5 feet), Link (7.92 inches...7 & 23/25ths inches)

Under this alternative method of navigation, the Great Pyramid's length was read as 756.25 feet or 756 feet and 3-inches. This means that two full circumnavigation's of the Pyramid @ 756.25 feet per side equated to a length of 6050 feet for 1-minute of Earth equatorial arc. This further meant that 1-degree of arc was 68.75 British Standard Miles of 5280 feet* and that the full circumference of the Earth at the equator was read as 24750-miles.

*Footnote: The huge astronomical Observatory at Goseck, Germany, 25-kilometres from where the Nebra Sky Disk was found, has a measured diameter for its outer circle of 175-meters. This was, undoubtedly, 6875 British standard inches of diameter or 6250 Saxon inches. Using PI @ 3.141818182, this equated to an outer design circumference of 1800 British feet, which is 21600 inches for the full circuit or 60-inches per degree of arc.

So, how does this navigational system compare to the calibration found upon the Nebra Sky Disk?

The diameter of the disk (12.6-inches or 1 Greek foot) X PI @ 22/7 = 39.6-inches or 5 Links of 7.92-inches each.

The sum total of inches in 24750-miles = 1568160000-inches, which is 39600 X 39600.

The circumference value of the disk would equate to 1/39600000th of the circumference of the Earth.

The literal diameter of the Earth is 7920 British miles, which is 3960-miles X 2.

On a disk with a circumference of 39.6-inches, there would be 36 positions of 1.1-inches. This disk is essentially a 360 degree system wherein the calibrations are set out according to the "11" family of distance increments.

The Northern German or Saxon foot was 1.1 British Standard feet or 13.2-inches. This means that the Nebra Sky Disk has a circumference of 3 Saxon feet of 12 X 1.1-inches.

There would be 4800 Saxon feet in a British Standard Mile of 5280-feet.

"Z" Holes circle at Stonehenge has a measured diameter of 132 feet or 120 Saxon feet. The "Z" Holes diameter X PI @ 3.141818182 = 414.72 feet, which is part of a mathematical progression related to the equatorial size of the Earth. The sum of 414.72-miles (414 &18/25ths) would be 1/60th of the 24883.2-mile circumference.


Well, you know the size of the Earth with relative accuracy. The true equatorial size figure that is used in modern times is 24902 British Standard miles, so, working to a reading of 24750-miles there's only about 150-miles of error and that's not going to effect the accuracy of positional plotting or navigation in limited areas like the Mediterranean or Atlantic. The ancient scientists already knew that the true size of the Earth was 12 X 12 X 12 X 12 X 1.2 British Standard Miles or 24883.2, which is only 18.8-miles off the accepted value of the 21st century. If they wished to be particularly pedantic and fussy they could make minuscule adjustments to calculate into the equation the additional finite precision.

The main thing is that you need a mathematical system to tell you exactly where you are in the ocean at all times.

In a sailing ship you're at the mercy of the wind to a very large degree and can't just set any course you want. To get to somewhere you'll have to zigzag across the ocean, often tacking into the wind or at an angle to the prevailing wind. So, you're going to have to make any journey in a series of legs and with a number of course changes en route, but despite all of the changes in direction you've got to know where you are in the ocean at all times. You have to have a very-easy-to-use system of positional plotting. Failure to have one means you're probably going to die, as the sea does not abide fools at all well nor compensate for any lack of knowledge and experience.

You have two choices of length values that you can use to calculate the distance travelled on each leg of your journey. You can mark out your linear distances completed per leg in Greek miles, which, when converted to a circle, can be read in British Miles (i.e. 1-Greek mile of 5250 feet X PI @ 22/7 = 16500 feet...which is 1 British League of 3.125 British Standard miles).

Alternatively, if you wish to calculate linear distances travelled for each leg in British Leagues or Miles, then the circles produced from these diameters will be sexagesimal and divisible by 360-degrees (i.e. 16500 feet X 3.141818182...essentially 3 & 39/ 275ths... = 51840 feet or 360 X 144...or 360 X 12 X 12.

So, using the literal system as found on the Nebra Sky Disk, which uses Greek increments for linear travel (diameter) converting to German / British "11" series increments of circumference, this is how navigation was accomplished:

Linear distances at sea were calculated in Greek miles. As each leg was completed in batches of completed miles the navigator would calculate the sea position, while the helmsman held a newly assigned course at a known degree angle around from North. Sometimes a leg of travel was long. Othertimes wind conditions necessitated that a leg of travel be relatively short. The important thing was to complete a leg in multiples of whole Greek miles and to always know the exact degree angle of travel. This ability to accurately calculate boat speed and distance covered came with experience and the navigator was obliged to do constant mental arithmetic.

At the completion of a leg the navigator would rule a line on the map chart, showing the distance covered and angle of that leg. He would then take his compass circle drawing instrument, set it to half the length of the leg and then go to the end of the line, where the boat was calculated to be situated on the map, and draw a circle based upon the radius of the completed leg. A diameter of, say, 5-Greek miles travelled would produce a circle with a circumference of 82500 feet or 5 British Leagues. Under this system 60 Greek Pygons of 45.833333 inches each (45 & 5/6ths inches) equated, in this case, to 1-degree of arc on the plotted navigational circle. Therefore, using well known values from the ancient parcel of measurements, the degree angle back to the point of departure or onwards to the destination could always be precisely calculated and the position at sea plotted with excellent relative accuracy.

The Sun boat depicted on the Nebra Sky Disk is, undoubtedly, indicating that one of the functions of the disk was to teach principles of navigation on land or at sea.


Displayed upon the Nebra Sky Disk are representations of both the Sun and Moon. This would indicate that the tutorials within the disk dealt with the cyclic periods of both, relative to the Earth's 365.25-day revolution around the Sun and the Moon's 354.375-day revolution around the Earth.

The solar aspect of the calendar is reasonably straightforward and easy to monitor over a period of 365.2422-days (365.25). The Moon's cycle is more complex and must be, ultimately, monitored over a period of 6798.36-days, which period the ancient mathematicians set at 6804-days. The reason for the very small amount of inbuilt or accepted error was to use perfectly factorable numbers to break the entire lunar period down into small fractions of time, reducible to seconds, minutes, hours, days, weeks or months, etc.

The calendar system, carried by the ancient Germans and other Europeans from their former homelands in Egypt and its environs was "Lunisolar" and tracked the movements of the Sun & Moon simultaneously in periods of 7-solars years or 7.2-lunar years.

To extract the calendar coding from the Nebra Sky Disk, one simply uses another variation on PI when converting its diameter to a circumference. Therefore:

12.6-inches X 3.125 (3 & 1/8th) = 39.375 (39 & 3/8ths).


The Khafre Pyramid of the Giza Plateau is Egypt's Pyramid of the Moon. To find its design length per side one simply refers to the length of the Great Pyramid, as the Khafre Pyramid is 15/16ths of that length Therefore:

756-feet ÷ 16 = 47.25-feet... X 15 = 708.75-feet.

The sum of 39.375 feet would be 1/18th of the length of the Khafre Pyramid or 1/72nd of its entire circumference. Therefore, under this assigned calibration on the circumference of the Sun Disk (39.375-inches), it would represent 1/864th of the Khafre Pyramid circuit or 1/216th of its side length. It might be interesting to note that the Sun is 864000-miles in diameter and the Moon is 2160-miles in diameter. Also, the Sun spends 2160-years in each house of the zodiac during the 25920-year period of the Precession of the Equinoxes. The ancient British Bushel volume was 2160 cubic inches.

With the length of the Khafre Pyramid set at 708.75 feet, half the length was 354.375-feet. The sum of 354.375-days is the duration of the lunar year, which is 11-days shorter than the solar year. Therefore, the sum of 39.375-days would equate to 1/9th of the lunar year.

The Khafre Pyramid (Egypt's Pyramid of the Moon) was also designed to demonstrate the geometric principle of the 3,4,5 triangle. Therefore, half the base length (adjacent) is 354.375-feet (3 X 118.125 feet); the centre base to the apex (opposite) had a design height of 472.5-feet (4 X 118.125-feet); the diagonal slope (hypotenuse) is 590.625-feet (5 X 118.125-feet). Therefore, using this assigned circumference on the Nebra Sky Disk (39.375-inches) it is 1/108th of the adjacent length, 1/144th of the opposite height and 1/180th of the hypotenuse diagonal.

The ancient Druids and their predecessors used a lunisolar Sabbatical calendar system, brought with them to Europe from Egypt, which ran uninterrupted for 7-solar years or 7.2-lunar years. The sum of 7-solar years was 2556.75-days (365.25-days X 7). The sum of 7.2-lunar years was 2551.5-days, or 5.25-days shorter.

To make the solar and lunar periods end on the same day, seven solar years later, the Druids observed an important ceremony. They commenced their solar count at the Summer Solstice & full Moon conjunction. On the sixth day after the Summer Solstice they held a solemn "mistletoe" culling ceremony, wherein they had one of their group climb a venerable Oak tree infested with the parasitic plant mistletoe, to cut sprigs of mistletoe that would fall down onto a white sheet. At the same time other Druids would dance around the tree singling, 'Hey derry, Derry down'. They would also sacrifice two white oxen on this day. From this day it would be 2551.5-days until the end of 7.2-lunar years. From the Solstice, 5.25-days earlier, it would be 2556.75-days till the end of 7-solar years.

Each week during 7-solar years would be exactly 7-days long. Each month would be 28-days in duration. For calendar-count convenience, there would be 13-months of 28-days or 364-days per year. The calendar was allowed to accrue 1.25-days of error per year for the 7-years until, at the end of the Sabbatical Year, there were 8.75-days of error, after which time there would be a calendar-correction festival. The next Sabbatical period would then commence and the calendar, altogether, ran for 7 X 7 Sabbatical Years until the beginning of the 50th or Jubilee Year, when there would be a major correction to render the calendar perfectly accurate.

In the 2551.5-days (7.2-lunar years) describing the lunar aspect of the Sabbatical Calendar count there were 64.8 periods of 39.375-days (945-hours). In the 7 X 7.2-lunar years aspect of the full Sabbatical count, there were 453.6 periods of 39.375-days. It's interesting to note that the true physical height of the Great Pyramid, which always rose to a flat floor altar on top (it never was designed or built to have a capstone), was 453.6-feet, which is a very important navigational number

A mathematical progression based upon 39.375 will produce both lunar and navigational numbers.

In the 6804-day count describing the lunar nutation cycle (major lunar standstill to minor lunar standstill and back to major lunar standstill again) there would be 172.8 periods of 39.375-days. It's interesting to note that a diameter of 55 feet (10 British merchant seaman fathoms or 50 Saxon feet creates a circle of 172.8-feet using PI @ 3.141818182 (3 & 39/275ths). One calculated diameter width of Silbury Hill in Southern England is 550 feet, which means an intended design circumference of 1728 feet using PI @ 3.141818182. The value given for a Celtic Royal cubit was 21-inches. Under this standard, one full circumnavigation of the Great Pyramid @ 756 feet per side was 1728 Celtic Royal Cubits.

So, the Nebra Sky Disk shows all of the attributes of a "memory device" for recalling the mathematical principles of "navigation" and the "Sabbatical Calendar" system. The Druidic teachers had to memorise all of these numbers, which described the various cycles or the equatorial size of the Earth. They then had to teach initiate students how to use the numbers for navigation on the sea or mapping the land, as well as keeping very accurately abreast of the positions of both the Sun and Moon within the lunisolar calendar system.

The count of 30 spherical dots (set out as constellations) is symbolic of the 30-day count system when describing the solar month, within the 12 positions of the zodiac, per annual revolution around the Sun. One of the spherical dots has no gold leaf on it and, speculating that it was designed like this, the count of starlet dots symbolically reduces to 29 (days). This would be in deference to the lunar count within the calendar system, which was 12-periods of 29.53125-days (29 & 17/32nds). If the dot missing its gold leaf overlay once had leaf on it, then there is yet another dot with a half circle stamped into it and this could mean the 29.53125-day count. Two other semi-hidden spheres in the right-hand horizon band (based upon the orientation of the upper pictures) might indicate an alternative count of 32 and related to quartering the Earth for 360-degree counts... 360 ÷ 32 = 11.25.

*Footnote: At both Brodgar Ring in Scotland or Avebury Henge's southern circle, the intended design diameter is 340.2-feet (324 Greek feet). This diameter coding is similar to the 34020-inch perimeter value of Khafre Pyramid (708.75 feet length per side X 4 X 12). It simultaneously relates to the 6804-day duration of the Lunar Nutation cycle (3402-days X 2). These shared diameters at Brodgar and Avebury expand to a circumference of 1063.125 feet, using PI @ 3.125. This means that 1-degree of arc on the symbolic circle was 2.953125-feet or 35.4375-inches, in homage to the lunar month of 29.53125-days or the lunar year @ 354.375-days. The outer design height of the Calendar of Coligny bronze plaque artefact was 2.953125-feet.

The two bands of gold to each side of the Nebra Sky Disk, indicating 82-degrees of horizon expanse, should describe the solstice rise & set positions, which fall about 41-degrees each side of the equinox rise and set positions, for the latitude of Goseck Observatory in Germany.

The green-blue patinated colouration of the disk, which is based upon actual paint and not corrosion, should represent both the "heavens and the Earth" simultaneously. The disk offers tutorials and mnemonic recall for what's happening on an astronomical or cyclic plane above, as well as a calendrical / seasonal or navigational plane below, over terra firma and its vast oceans.

It would appear that within the Nebra Sky Disk layout of objects, in conjunction with the circuit calibration holes, further distance and angle codes are encrypted. This concept will need to be computer tested and verified within the exacting confines of AutoCAD architectural program. Some preliminary analysis by this researcher, done over a perfectly scaled drawing of the Nebra Disk, suggests code bearing attributes for every marked position of the disk. In consideration of the fact that the metals that made up the artefact were relatively rare and either precious or semi-precious, no opportunity to encrypt codes of position would have been lost. There would have been no arbitrary and meaningless design work that was merely decorative, and every marked position contained a tutorial. For example:

The solar orb on the disk appears to have been designed to have a diameter of 3.96-inches or 1/10th of a Saxon foot. The true diameter of the Earth is 7920-miles, which is 3960-miles X 2. In a very literal way, the orb refers to the dimensions of the Earth. Therefore: An Earth diameter of 7920-miles X PI @ 3.141818182 = 24883.2-miles of equatorial circumference, which is 12 X 12 X 12 X 12 X 1.2-miles.

This coding is similar to the length between the two horns of the crescent Moon design on the disk, which appears to code 4.95 British Standard inches or 4.5 Saxon-inches. Again, this is a mathematical progression within the "11" family of numbers that provides values related to the equatorial size of the Earth...undsoweiter...There remains much deciphering work to do.

For a full explanation of how the Nebra Sky Disk related to the calendar and navigation determinations see:

The Calendar of Coligny article within this website.

Sample Celtic gold coins, which carry astronomical symbolism very similar in design to the Sky Disk of Nebra. These features include:

A Celtic Torque, taken from the grave of the Princess of Vix, (circa 500 - 600 BC). It weighs 480 grams, which converts fluidly to 16.875 ounces (16 & 7/8ths). The ancient Celtic royal families, with Druidic advisors and counsellors, were the overseers, guarantors and guardians of precise "weights, measures and volumes" for the general populations and their marketplace transactions. Many venerated objects of royal office carried codes of length, volume or weight and acted as "standards". The ancient kings of Ireland, then Scotland and later England, were "crowned" (coronated) while standing or sitting upon the "Stone of Scone", which was built to coded attributes of size and weight. The stone later sat beneath the throne of the monarch, whose responsibility it was to maintain "civilisation", based upon the ancient parcel of knowledge handed down from sage forebears.

The Celtic Torque of the Princess of Vix was, undoubtedly, carefully fabricated and coded in weight to be in direct ratio to both the Greek Commercial Talent or the Tridrachm (Beqa) gold standard Talent. It represents 1/80th of the Talent weights in both of these ancient Greek standards, which in turn are related to the ancient Assyrian "heavy" & "light" weight standards. The Torque depicts the rising and setting orb of either the Sun or Moon and shows a "Greek Pegasus" flying horse ascending upwards on the orb to the East (right) and downwards on the orb to the West (left). In terms of the grain weights inherent within the artefact or within the Greek Commercial & Tridrachm standards, the numbers produced are lunar and 16.875-days (504-hours) would be 1/21st-part of the lunar year of 354.375-days duration.

On British "Henge" observatories, the outer embankments, in combination with the ditch, can represent a single curved serpent (as at Mt. Pleasant observatory, Dorchester, Dorset) or two serpents (as at Stonehenge), the heads of which are at each side of the "Avenue". Centrally located between the two, open-mouthed, serpents at Stonehenge is an orb structure made up of a circle of posts that was once used for calculation functions in relation to site centre. The concentric rings of the post circle represent the orb or egg being swallowed by the snake. This same occurrence is found depicted in the landscape in Southern France (near Rennes le Chateau) or at Serpent Mound in Ohio, USA and is a very ancient cultural idiosyncrasy that migrated from Europe to North American by about 3000 BC. North American embankment structures, like the Octagon of Newark, Ohio carry all of the same, coded lunisolar calendar or navigational mathematical principles, incorporating the same length and angle ratios, as the structures of ancient Europe and the Mediterranean. The selfsame cousin nations, working from the same parcel of numerically coded astronomical or navigational scientific principles, built mathematically related structures around the entire globe, including all over the "Far Isles" at the very ends of the Earth, New Zealand.

In Summary:

All of the known German observatory rings, whether large or small, will demonstrate variations on this mathematical coding. All will carry a code in the diameter, which expands to a further code in the circumference, using slight variations on PI. All ancient German volume vessels or all "old standard" weights, based upon grains, will carry lunar or navigational coding in either their cubic inch capacities or grain weight counts. All known ancient measuring rods, shared by the cousin nations, will be based upon the same number families and prove to be in direct ratio to each other. All of the important numbers of antiquity shared by the cousin European peoples, were derived from the same integrated parcel of calendrical or navigational codes. These number systems and the sciences that they described, were devised in much more ancient homelands, long before ethnic European (Nordic) peoples migrated from an increasingly arid Egypt or its environs to the verdant territories of Europe, in about 5000 BC.

See: Weights, Measures & Volumes of the ancient Mediterranean.

Martin Doutré

April 2006.

To be continued.