On Sunday, April 27, 2003, at 12:17 AM, fer j. de vries wrote:
The difference is there is no difference.
January 1st -4712 is the same as January 1st 4713 BC
( I think the 4173 in your message is a typo error)
It certainly was - I only noticed it after the message had been posted.
Atronomers count including the year 0 so the year before 1 is 0 and
the year
before that is -1.
Historians count without the year 0 so the year before 1 is 1 BC and
the
year before that is -2 BC.
Therefore we get two starting points for the Julian day:
-4712
4713 BC
Jean Meeus uses the astronomical way because it's easier to calculate
the JD
for the Julian calendar.
I notice that Jean Meeus is also particular about referring to JD as
Julian Day rather than Julian Date.
By the way is the second edition of his book much changed from the
first edition ? Can anybody help with a comparison of the two editions.
-
