Some new ideas

Possible original Methods used to set up Alignments

(1)      Knowledge / Skills required

Neolithic people would have spent much time in the open and would have known the night sky and the movements of celestial objects well.

They would have noticed that the moon was infrequently but regularly much higher or lower in the sky than the sun.  This would have been much more obvious from more northern latitudes.   So eventually it is suggested it would have been noticed :- :-

• That every 18.6 years the moon came to a maximum north and south

Further observation (using alignments by now):-

• That the moon did not come smoothly up to and away from the maximum

And with further, more precise observations, probably over many generations:-

• That the moon came to the maximum (north and south) in a series of little waves each of similar size and regular interval,   and (probably)
• That eclipses, when they occurred, did so at the full moon and during the time of the maximum (i.e. of one or other of the little waves).

If eclipses were predicted then it would have been necessary to keep a tally of the 173 days period of the ‘wobble’.  Probably the Minor Standstill sites served as a check.

The only skills required, other than careful thought, would have been the ability to count and to keep records in some suitable form.

No other knowledge or skills would be required.   There was no need to understand the reasons for the moon’s movements. No need to understand the concept of declination.

The only reason that it is now necessary to use a theodolite and trigonometry (or computer programmes) is that because of precession the moon no longer rises and sets were it would have nearly 4000 years ago.   We have to reconstruct the past.

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(2) Possible methods used

It is generally considered that the setting up of precise alignments during the period in question would have been difficult; some might even say perhaps impossible.    Some of the difficulties to be expected have been discussed previously.

It is generally believed that the moon had been observed in northern Europe with probably increasing refinement at least since 3000BC.

If we accept the results here presented then it must follow that at some date before about 1800BC

• The Major Standstill,
• The ‘wobble’ and probably
• The period of the ‘wobble’         had been discovered.

 

Let us also suppose that by lengthy trial and error a few alignments in a suitable region (probably in western Scotland) had been set up, but, perhaps for a variety of reasons, more were wanted.  Just maybe somebody thought of the following possible method, or perhaps it seemed obvious:-

Use the Stars to transfer alignments

The moon at the extreme positions has, what we would now call, a particular declination.  The declination of stars is, over a short period of a few years, essentially unchanging.          So at any already discovered lunar site, from the normal observing position, note how far north or south of the foresight one of the brighter stars rises/sets by any convenient method.   Even compared to a finger width at arms length, but probably better would be a stick of some sort.  Anything that we would now say determines the angular difference between the star and the known foresight when they are closest.  (It would be better for the star to be north of the foresight so that it will be readily visible when it is closest to the foresight(s)).  Then, knowing the angular distance, the observer takes the ‘measuring stick’ to the likely backsight place for a promising new foresight.  Determining the approximate position for the new backsight would be straightforward by using the same star and measurement method.  The observer would simply move around until a suitable position was found.  This could be repeated as often as required over many nights as long as the same star rose/set in darkness.    The declination of the new foresight/backsight  would automatically be close to being correct.  In effect what we would now call the declination is being copied to a new site.   Furthermore the work could be done at any time between standstills and change of latitude would be unimportant. (The Lunar parallax changes with latitude, but only slightly.  About 0’.6 arc / deg of latitude around 50 - 60º  north).  Doubtless ‘fine tuning’ would be required at the next Major Standstill.    Using this method, or some related method, a team of trained observers could set up a whole network of alignments during perhaps two standstills using known ones as templates.  (See Table 1 below)

In a sense there was no need to ‘keep reinventing the wheel’.

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Parallax

 The question of the observed precision of the alignments remains.

Two possibilities, assuming that the above method was used, are:-

Either the mean parallax position had been found during the ‘trial and error period’ and so this was transferred

Or by chance the moon was close to mean parallax at the end of the ‘trial and error period,’ and that position was transferred. (About 1760 BC ?? MLO p82)

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Climate It is believed that the climate in the Neolithic/ Early Bronze Age in Britain was very benign – perhaps even Mediterranean.  This was the Sub-boreal ( about 4000BC – 1400BC.)    (Wood 1978, pp182-184)

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Table 1

Approximate declinations of suitable brighter stars in 1700BC

(Magnitudes:-   Stars would be dimmed by about 2 mag. at 4º elevation and 3 mag. at 1º elevation.   Mag. 6 is considered to be the limit of naked eye visibility, so even the least bright of these stars would just be visible at 1º elevation in a clear dark sky.)

 

Name		Declination	Magnitude
Capella	α Aur.	32º.5	0.1
Denebol	β Leo	32º.0	2.2
Mirfak	α  Per.	31º.2	1.8
Castor	α Gem.	29º.9	1.6
Elnath	β  Aur.	17º.0	1.7
Sirius	α  Can. Maj	-19º.8	-1.6
---	γ Cen.	-29º.2	2.4
Adhara	ε Can. Maj.	-30º.0	1.5