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I have wondered about events, especially those in some way based on lunar
calendars that do not really correspond to ours, such as the high holy days
on the Jewish calendar (http://bnaibrith.org/caln.html), with nine leap
years, containing a leap month, distributed over nineteen years. That's
almost but not quite one every three years... Would this cycle repeat itself
every 532 years (nineteen times twenty-eight)? Or would the eccentricities
of our centessimal leap years prevent that? Various Orthodox churches use
the Gregorian calendar for their holidays, some with different
ecclesiastical timetables. Unfortunately, my understanding of the details of
these is inadequate to this discussion.

A web search did turn up the following quickly enough. Easter (which dates
to the first Sunday after the first full moon on the ecclesiastical calendar
after the Spring / vernal Equinox - see
http://www3.kumc.edu/diversity/easter.html, or
http://aa.usno.navy.mil/AA/faq/docs/easter.html for code to compute the date
of Easter) does vary. Take two non-leap years that begin on a Monday. In
1985 Easter fell on April 7th, while in 1991 it fell on March 31st. So
companies that are in some way affected by Easter or Good Friday would still
need to calculate this for the year in question.

I understand that the Chinese New Year gets celebrated in Hawaii, and I'm
sure there are some interesting stories out there. None of our company
holidays present a problem (New Year's, Memorial Day, Independence Day,
Labor Day, Thanksgiving and the day after, and Christmas), and this probably
does not represent the biggest challenge any of us face.

I have started saving old calendars which have the year prominently
displayed, to hang up when their turn comes around again, for the perverse
pleasure of surprising co-workers and other innocent passers-by. But certain
holidays will not quite work out when that year comes around again.

Gregory Stigers
http://www.cgiusa.com

-----Original Message-----
From: Stan Sieler [mailto:[log in to unmask]]
Sent: Wednesday, September 22, 1999 8:18 PM
To: [log in to unmask]
Subject: Re: Y2K Testing.

Barry is 100% correct.

There are only 14 different possible "calendars", where a calendar is
defined
as the layout of a single year.

However...it takes 28 years to make a complete sequence.
<snip>
Note that for any given starting-day-of-the week,
the calendar is identical for each of the three years that aren't a leap
year.
(E.g., 1973 = 1979 = 1990)