"... the yearly 'path' of the sun, from its rising point south of east at the winter solstice to its setting point furthest north of west at the summer solstice is not fixed and immutable but rather undergoes slow, almost imperceptible changes drawn out over very long periods of time.

These changes, which should not be confused with the astronomical cycle of precession, correspond to actual changes in the tilt of the earth's axis in relation to the plane of its orbit round the sun - a phenomenon known as the 'obliquity cycle', which has a duration of more than 40,000 years.

Because these changes can be modelled mathematically

it is theoretically possible, if you trust the accuracy of the ancient builders, to work out from the degree to which a temple is misalgined, the date at which it must originally have been surveyed (i.e. the date at which it would have pointed accurately at a given solstitial sunrise or sunset)." (Hancock 3)

Posnansky used this formula: ω = 23^o 27´ 8.26´´  -  468.44´´ t  -  0.60´´ t²  +  1.83´´ t³  and with that reached an age about 15,000 BP for the alignments of Tiahuanaco. I cannot get that formula to work.