Bernard wrote:
>So is it coincidental that Trinus Samoni falls on same day of year as St Patrick's Day ? 
(Seventeen day of the first month of the year.)

Well that may not be a coincidence at all, the 17th day of the first month.  It could well be being used symbolically.  

I have recently been working on how the calendar may sit within the year.  Placing it on a series of festivals and solstices/equinoxes is no problem, but having done that it seemed that if this placing were correct, it should provide 
information about other significant notations that aren't immediately obvious.  And this has turned out to be so.  In
the case of the anomalous swap between SAM 3 and SAM 17 and the related unique NSDS at GIAM 17,  this 
is quite a stunning moment in the sky.  But oddly not one that hasn't been suggested before in other contexts 
in relation to ancient monuments.  This event is the moment when the sun on its ecliptic crosses the Milky Way, in SAMonios it crosses into the summer zodiac region, and in GIAM it crosses into the winter half of the zodiac.  The reason why SAM 3 and 17 are swapped, is that this crossing point doesn't occur at precisely 6 lunar months apart, so we take the exact day and swap it to the position required for the sun's crossing.  That's called having your cake and eating it :-) 

Helen