REFRACTION AND PRECISE LUNAR ALIGNMENTS

Abstract

During a major standstill the maximum declination of the moon at successive lunations varies by only a

small amount. Observing the extreme north/south position of the moon would require an alignment of high

precision. Alexander Thom believed that this had been done in the Early Bronze Age. Most of the claimed

sites are in Scotland.

Atmospheric conditions, especially variation in temperature and pressure can cause variation in atmos

pheric refraction, particularly at very low altitude. Large variations have been found to be common in Chile

and North America as result of which Bradley Schaefer has stated that the results claimed by Thom would

not be possible. However there is no reason per se why atmospheric conditions in other parts of the world

should be relevant to Scotland. Investigations in Scotland have found that refraction variation, even down to

one degree altitude, is typically less than one minute of arc. It is concluded, therefore, that it is unreasonable

to claim that refraction variation elsewhere would prevent the possible existence of precise lunar alignments

in Scotland. Recent investigations by the present author, provides evidence for the possible existence of such

alignments.