|English pages||Megalithic astronomy|
|General info > Method - Observatories - Geometry - Date-lines - Precession|
Precession is the slowly tolling movement of the earth ax, caused by influence of Sun and Moon.
Consequences of precession
Caused by precession actual positions of celestial objects will be different from the positions when an old observation system was built. This made relations between stone formations and celestial objects are difficult to examine. Astronomers use complex computer software for that kind of calculations...
Precession also has consequences for our so-called Pole Star. In megalith builders' time that star had no no meaning. They probably used one of the stars in the sign 'Dragon' as pole star.
Changing angle of declination
Also the position of the points of sunrise and
sunset are changing by precession. Earth's declination angle (angle
equator) changes slowly. In fact sunset isn't showing yearly on exact the same
point. Per century the change of the azimuth (point of
sunrise) is about 0.02 degrees, or a shift about 0.2 degrees per 1000
year. So megalith builders saw sunrise about one degree more north than we do.
Declination angles: (According to J.E.Wood)
In consequence precession we see other stars on a specific moment (for example on spring-equinox) than a few thousand years ago. The zodiac seems to shift slowly across the firmament.
Today spring-equinox stands in the constellation Pisces.
Cause of the sunshine the constellation isn't visible on that specific moment.
We can see Pisces during night in autumn.