On Fri, May 24, 2019 at 8:16 AM Rory McCann <r...@technomancy.org> wrote: > On 24/05/2019 02:44, Kevin Kenny wrote: > > 'easter' suffices for the entirety of the Christian calendar > > Nope! 1,000 years ago the Christian church(s) had the "East West > Schism", resulting in Orthodox Christianty in the east, and > Catholic/Prodestant Christianity in the west. The 2 sides often disagree > about when Easter is. > > https://en.wikipedia.org/wiki/Template:Dates_for_Easter > > As far as I can tell the `opening_hours` syntax on the wiki doesn't > specify which easter, but I presume it refers to the locally observed > easter.
You're right, I oversimplified. In the Byzantine church calendar, the fixed observances are tied to specific dates, and the movable ones are tied to the date of Easter, so the same assertion applies that Easter is the only date that must be specified separately. Julian Easter is a different day about 2/3 of the time. Not only are the calendars 13 days apart, but the algorithm for calculating the date of Easter uses a different approximation to the orbit of the Moon. Aside from that, for the next 80 years, Julian-calendar fixed holidays are at a constant offset from Gregorian-calendar ones. Few sets of 'opening_hour's will have that sort of longevity. And I'm fine with having julian_easter be a separate specification. _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
