How do we know about precession?
1 Answer
Jul 21, 2016
Slight displacement of equinox location and its little later occurrence, over years..
Explanation:
The Biannual Equinox event ( about March 21 and about September
23 ) occurs at a location on the equator, twice in a year. The noon
Sun is right over head there ( somewhere near New Papua Guinea
Island, South of Indonesia, for March 21 vernal equinox ), at
that instant.
Noticeably, this instant and location change over centuries.
It is estimated that, longitudinally, this location makes one round
upon the equator, in about 258 centuries (Great Year)
The corresponding event at other latitudes relates to minimum
noon-shadow ( against no shadow at equinox ), at the same noon.
and longitude.
