[LEAPSECS] Reliability

[Zefram]

Magnus Danielson wrote:

>                                                      They also made a 

>correction for the accumulate error to restore phase relationships.


Except that this correction was faulty.  By the mid 16th century, the
phase relationship between the seasons and the calendar had shifted
about 12.5 days since the inception of the Julian calendar (45 BCE).
Applying the knowledge that went into constructing the Gregorian calendar,
an attempt to correct for this shift would have amounted to skipping 12
calendar dates.  (They slightly underestimated the degree of shift.)

Instead they skipped 10 calendar dates.  This was because they didn't
aim to restore the original phase relationship of the Julian calendar.
Instead, they aimed to restore the already-shifted phase relationship
that had existed at the time of the Council of Nicea (325 CE).  The phase
shift from then until the calendar reform was about 9.8 days.

So they synchronised (as best they could) to the wrong phase, locking
into the calendar the very error they were supposedly fixing.

People are dumb.  (Sorry, I've run out of highbrow conclusions to draw
from this sort of thing.)

-zefram