Re: Calculate date of Easter or Good Friday

From	Michael S <already5chosen@yahoo.com>
Newsgroups	comp.lang.c
Subject	Re: Calculate date of Easter or Good Friday
Date	2024-02-27 14:36 +0200
Organization	A noiseless patient Spider
Message-ID	<20240227143658.0000555e@yahoo.com> (permalink)
References	<urdmac$1d3vr$1@dont-email.me> <urds3c$1e8e4$3@dont-email.me> <1bplwj84v5.fsf@pfeifferfamily.net> <20240227131244.00003360@yahoo.com>

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On Tue, 27 Feb 2024 13:12:44 +0200
Michael S <already5chosen@yahoo.com> wrote:

> On Mon, 26 Feb 2024 11:20:14 -0700
> Joe Pfeiffer <pfeiffer@cs.nmsu.edu> wrote:
> 
> > Lawrence D'Oliveiro <ldo@nz.invalid> writes:
> >   
> > > On Sat, 24 Feb 2024 21:15:56 -0000 (UTC), Mike Sanders wrote:
> > >    
> > >> Calculate the date of Easter Sunday or Good Friday:    
> > >
> > > Did you know that one of the requirements of the rules was that
> > > Easter would never coincide with Passover? Because the sight of
> > > Christians celebrating together with Jews was seen as heretical or
> > > something ...    
> > 
> > That's an Eastern Orthodox rule, not Western.  Last year (western)
> > Easter was April 9, while Passover was April 5 through 13 (this year
> > they don't overlap).  
> 
> This year Western Easter does not overlap with Passover because of
> approximately four day difference in definition of official start of
> Spring. When there is a full moon between 21st and 24th of Martch, by
> Western rules it's already Spring, but by Jewish rules it's still
> Winter and does not count.
> It happens approximately 3 times in 19-year cycle. Or, may be, exactly
> 3 times, I don't know for sure.
> So, it seems, Western Easter overlaps with Passover in overwhelming
> majority of years - 16 out of 19.
> 

P.S.
Eastern Easter, more properly called Pascha, rarely coincides with
Passover week, but not by ideological design, as insinuated by Lawrence
D'Oliveiro. It happens because, due to accumulated errors, Julian
Spring starts ~15 days after solar equinox while Jewish Spring starts
~5 days after solar equinox*.

Despite that, sometimes Pascha does happen during Passover. The next
such time will be in 2028, where Pascha will be in the last day of
Passover. I would think that few centuries ago it happened more often
and 1000 years ago it happened most of the time. 

* - it's more complicated, really, but for practical purposes of
  calculation of Passover day the above holds.

Thread

Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-24 21:15 +0000
  Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-24 22:54 +0000
    Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-24 23:57 +0100
      Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-24 23:02 +0000
        Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-25 02:00 +0100
          Re: Calculate date of Easter or Good Friday Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-25 02:27 +0000
          Re: Calculate date of Easter or Good Friday Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-02-25 16:58 +0000
            Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-25 18:50 +0100
            Re: Calculate date of Easter or Good Friday Dan Purgert <dan@djph.net> - 2024-02-26 12:43 +0000
        Re: Calculate date of Easter or Good Friday Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-24 18:00 -0800
        Re: Calculate date of Easter or Good Friday Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2024-02-26 11:24 -0700
          Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-26 23:20 +0000
            Re: Calculate date of Easter or Good Friday scott@slp53.sl.home (Scott Lurndal) - 2024-02-26 23:31 +0000
              Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-27 12:50 +0100
            Re: Calculate date of Easter or Good Friday James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-02-27 05:02 -0500
              Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-27 22:48 +0000
                Re: Calculate date of Easter or Good Friday James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-02-27 19:06 -0500
                Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-28 00:11 +0000
                Re: Calculate date of Easter or Good Friday James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-02-27 19:24 -0500
                Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-28 20:47 +0000
                Re: Calculate date of Easter or Good Friday Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-28 14:06 -0800
                Re: Calculate date of Easter or Good Friday Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-28 22:20 +0000
                Re: Calculate date of Easter or Good Friday James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-02-29 13:21 -0500
              Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-27 22:50 +0000
                Re: Calculate date of Easter or Good Friday James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-02-27 19:41 -0500
                Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-28 13:13 +0100
    Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-25 01:33 +0000
      Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-25 06:20 +0000
    Re: Calculate date of Easter or Good Friday G <g@nowhere.invalid> - 2024-02-26 09:47 +0000
    Re: Calculate date of Easter or Good Friday Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2024-02-26 11:20 -0700
      Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-27 10:08 +0100
        Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-27 13:00 +0100
      Re: Calculate date of Easter or Good Friday Michael S <already5chosen@yahoo.com> - 2024-02-27 13:12 +0200
        Re: Calculate date of Easter or Good Friday Michael S <already5chosen@yahoo.com> - 2024-02-27 14:36 +0200
  Re: Calculate date of Easter or Good Friday Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-02-25 17:39 +0000
    Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-26 03:12 +0000
      Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 05:20 +0100
        Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-26 14:26 +0000
          Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 16:31 +0100
          [OT] personal things (was Re: Calculate date of Easter or Good Friday) Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 16:43 +0100
        Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-26 14:32 +0000
          [OT] Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 17:10 +0100
            Re: [OT] Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-26 18:26 +0100
    Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-26 11:45 +0100
      Re: Calculate date of Easter or Good Friday Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-26 13:04 +0000
        Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-26 15:46 +0100
          Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 16:17 +0100
            Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 17:15 +0100
      Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-26 14:38 +0000
        Re: Calculate date of Easter or Good Friday scott@slp53.sl.home (Scott Lurndal) - 2024-02-26 16:29 +0000
          Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-26 19:54 +0000
            Re: Calculate date of Easter or Good Friday scott@slp53.sl.home (Scott Lurndal) - 2024-02-26 20:06 +0000
              Re: Calculate date of Easter or Good Friday porkchop@invalid.foo (Mike Sanders) - 2024-02-26 21:18 +0000
              Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-27 00:59 +0000
        Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-26 18:07 +0100
      Re: Calculate date of Easter or Good Friday Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-02-26 16:09 +0100
      Re: Calculate date of Easter or Good Friday Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-02-26 17:26 +0000
        Re: Calculate date of Easter or Good Friday David Brown <david.brown@hesbynett.no> - 2024-02-27 10:17 +0100
        Re: Calculate date of Easter or Good Friday Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-03 11:05 -0800
      Re: Calculate date of Easter or Good Friday vallor <vallor@cultnix.org> - 2024-02-27 01:28 +0000
        Re: Calculate date of Easter or Good Friday Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-27 02:25 +0000
        Re: Calculate date of Easter or Good Friday Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-03 10:03 -0800
    Re: Calculate date of Easter or Good Friday Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-28 01:54 +0000
      Re: Calculate date of Easter or Good Friday Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-03 10:23 -0800

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