I took a look at an astronomical ephemeris, which is a book that details tracking of heavenly bodies across the skies, and set out to try to find patterns to the occurance of total lunar eclipses. There are 3 types of lunar eclipse. The first type is called an 'appulse' which means that only part of the sun's rays enter the atmosphere of the earth before striking the lunar surface as a shadow. This shadow will show up as a tiny dark curve on one of the full moon's limbs which is not very noticable to the naked eye. The second type is referred to as a partial eclipse where the earth will in part block out the sun's rays from reaching the moon and a definite dark shadow is cast across the moon's face.This will only cast a partial shadow on the moon's surface. The third type, the total eclipse, means a red-orange coloured shadow highlights the whole of the moon's surface and this phenonomen lasts approx. 1 hour 45 mins. The most interesting thing about lunar eclipses as opposed to solar ones , is that a lunar eclipse can be seen from one entire hemisphere of the earth, whereas, with a solar eclipse, the shadow path on the earth is relatively much smaller and focused.

I recorded all total lunar eclipses for the first 54 years of the 20th century, and found each moon's rising azimuth at Loughcrew, to 1° altitude. What I discovered is that certain cycles, appear and reappear in firstly, 3 year cycles, which you could not predict if using this 3 year method, where the eclipse would occur. However another longer cycle unmasked itself.

This is 11.1 years in its periodicity. Every 11.1 years a total eclipse will repeat itself to within a very narrow azimuth range from the prior eclipse and within 1 to 2 days of the calendar day and date of the prior one. I translated this 11.1 years into lunations (a period of time between successive same phases of the moon, ie. new moon to next new moon or full to next full) and it came out to be 137.05 lunations.That is 137 full moons later another lunar eclipse will occur at the location and azimuth of the previous total lunar eclipse 11.1 years earlier. This is very simple to use on computers but could the Neoliths have known this periodicity. Tallying 137 lunations over 11 years is a daunting task, some method of recording each and every full moon would have to be undertaken. What about weather conditions , could they have taken some shortcuts, to recording? We know, as they would have known, that you can have 3 full moons over 3 days roughly every 29.5 calendar days. This is called the synodic cycle of the moon. But they may not have known which of these 3 full moons would be the most fullest. That would have firstly meant noticing a total lunar eclipse within the 3 full moon period and then predicting where the total eclipse would occur 11 years later! If they tried to use the smaller 3 year cycle, it becomes clearly erratic and chaotic to apply. But this 11.1 year cycle is a steady constant. Slowly however the totality of the eclipses over this cycle decays so that you end up finding near total eclipses after a long period of full total eclipses.

To gauge the extent of the spread of full moons , I used this 11.1 year cycle just for the full moons that occured around the Vernal(Spring) and Autumnal equinoxes in the Neolithic time of the 3rd phase of Loughcrew construction.

From the vernal equinox time we can see a definite pattern to the rising moon azimuths, a regularity exists, sometimes in 10° intervals, sometimes 9° others 17°. We also get a 72% hit rate for the rising moons within Loughcrew cairns. What's beginning to become apparent is the incidence of azimuths 1° to 2° apart. Loughcrew seems to be constructed coincidentally this very way.

Again on the Autumnal equinox, we find a hit rate up to 77% for the cairns and there's more incidences of 2° azimuth intervals.
When I found the full moons operating like this, then I thought why not lunar eclipses themselves. So I essentially did more or less the same thing for total lunar eclipses. I picked one total eclipse and advanced 11.1 years, found the next one and so on until the total phase of the cycle faded out into partial eclipses. I noted the moonrise azimuths and found a good deal of them corresponded with some of the cairn alignments. I found multiple cycles based on the 11.1 years. They occurred at 22.2 years, 55.5 years, 77.7 years etc. In fact you could track lunar eclipses by latching onto any singular eclipse time and moving back and forth, its so simple and reliable, the Neolithics had to know about this. I've compiled a few more tables below that shows the details.

The hit rate here in this 55.5 year cycle is very poor but we do get a welcome rising lunar eclipse in total seen framed in the entrance of cairn L in 3289BC.What's every interesting with this 109° is that the cycle of 11.1 years is a constant. Proof of this comes on Apr 22, 1921 AD when a rising moon becomes an eclipsed one. It rises exactly on 109° azimuth at 1° alt.!! Unfortunately this particular eclipse occurred just below the Loughcrew horizon.

We have two separate cycles here, broken up by a partial eclipse that's almost total. There's an 11.1 year cycle starting at 3292BC and a 22.2 year one starting at 3325BC. Here the cairn hit rate is much better than the above table.

Here we have a 66.6 year cycle with one partial eclipse marring the run of total eclipses. The hit rate for the cairns is very high.

Solar Eclipses

Well, could you use the 11.1 year cycle to determine solar eclipses from your position? Not unless you are prepared for erratic behaviour. It just dosen't translate well with sun eclipses and this, as I've mentioned before, has everything to do with the narrow eclipse path of the sun's shadow over the earth. If you found a total solar eclipse by the 11.1 year cycle then there's no guarantee the next one 11.1 years earlier or later would be an eclipse. In fact, it may not even be partial!! What is interesting is the artistic representation of solar eclipses on megalithic stonework having concentric circles. Concentric circles are in abundance at Loughcrew, especially at Cairn H. I've compiled a grouping of solar eclipses as seen from Loughcrew in Neolithic times. Two of the eclipses I have redlined as they seem to show the passage of 235 lunations i.e. 19 tropical years.In fact this is the famous Metonic cycle that the Greek Meton discovered. If you advance exactly 19 years from a particular date, where you have say, a full moon, or a solar eclipse etc. you will arrive at almost the same azimuth and altitude. For Cairn L at the 119° azimuth, we have full moons occurring at 31th May in 3235BC, 3254BC, 3273BC(30thMay),3330BC, and 3311BC which is a total lunar eclipse just rising into the entrance! So this works even better than the 11.1 year cycle but it is a longer cycle and twice as difficult to track having 235 lunations as opposed to 135.07. Could the Neolithics have known about this? Somehow I doubt it, too big an expanse of time to measure, even the 11.1 year cycle looks difficult to do.There had to be some short cuts within these cycles so that interim measurements could be taken without having to resort to counting every single lunation.

The 11.1 Year Cycle and.........

It occurred to me as I used this 11.1 year cycle that there existed another 11 year cycle of a solar nature. That is, sun spot activity, at its peak follows an 11 year cycle. We now shift our focus to a brief lesson in Astrophysics. Sun spots are caused when a solar substance called plasma is ejected at high speeds from the sun's boiling surface. Its composed of protons and electrons and it can easily travel the 93 million mile distance to our earth. When it gets to the Van Allen radiation belts, the plasma stream is deflected and directed along the protective belts towards the North and South poles of our planet. At our poles there is no Van Allen belt protection from harmful solar xray radiation in the form of ionisation.This is because the belts are doughnut shaped and have a hole at either pole end. Therefore the plasma can enter the atmosphere and cascade down interacting with oxygen and nitrogen atoms in the air. At least two effects are known to exist with peak periods of high 'solar wind' activity which is what this is. One effect is invisible, the other very much the opposite. You can get magnetic and electrical distortions that come down to the ground. These fluctuations can disrupt electrical transformers and sub stations around the world. The visible effect is the occurrance of the Aurora Borealis and Aurora Australis. These are better known as the Northern and Southern lights which are usually viewable outside of the solar wind peaks at high latitudes, say in Greenland, Finland, Alaska etc. When a peak comes every 11 years, the spectacle of lights increases in intensity and drops to a low latitude sometimes as low as 40° Northern lights produce, strange errie green and red overhead displays. They form 'curtains' and 'arcs' and yes 'RAYLIKE' emissions when seen overhead. Now these peaks of activity occur around eclipses, especially eclipses that take part close together. In 1981 there was a peak of Northern and Southern light displays. In that year you had 2 sets of eclipses close together, an annular lunar eclipse on Jan 20th, then 15 days later, an annular solar eclipse on Feb 4th. That's one set, then on 17th July you had a partial lunar eclipse and strangely 14 days later!! a total solar eclipse. Now if you picked any of the eclipses above and applied the 11.1 year cycle, you would be paralleling the sun spot peak period. Makes you wonder!!!

Preliminary Findings

1. The entire ridge is devoted to the tracking of primarily the Moon, in all its phases and aspects ,and to a lesser extent, the Sun.
   
2. The majority of alignments face to the area of rising Full Moons, and by extention, rising Lunar eclipses.


3. A series of standing stones on the low ground surrounding the ridge also primarily track the Moon across the tops of the largest cairns, with secondary tracking to most of the stars in the Constellation Orion.


4. The standing stone inside Cairn L, on Carnbane West, represents the function of the low ground standing stones and signifies the partial solar eclipse of 30th Nov. 3321BC.


5. Cairn T is the only cairn that has a primary function to the Solar equinoxes in Neolithic times.


6. A proposed construct date for Phase III at Loughcrew, based on the standing stones, astronomically, gives us 3300BC +/- 30.


7. Finally, based on stellar alignments to the phase I and II cairns, Phase I could have started around 3480BC and Phase II, at 3400BC.

BIBLIOGRAPHY

1. Brennan, Martin,(1994) The Stones of Time, Inner Traditions International, Vermont.
2. Cooney, Gabriel,(2000) Landscapes of Neolithic Ireland, Routledge, London & New York.
3. Mc Mann , Jean,(1993) Loughcrew The Cairns, A Guide, After Hours Books, Oldcastle.

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© Paul Griffin, 1999