function [ m, d ] = easter_julian2 ( y ) %*****************************************************************************80 % %% EASTER_JULIAN2 computes the date of Easter in the Julian calendar. % % Discussion: % % This computation for the date of Easter uses the Dionysian % canon that applied to the Julian calendar. The determination % of the date of Easter changed at the same time that the calendar % was modified to use the Gregorian system. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 17 June 2012 % % Author: % % John Burkardt % % Reference: % % Edward Richards, % Algorithm N, % Mapping Time, The Calendar and Its History, % Oxford, 1999, page 365. % % Parameters: % % Input, integer Y, the year. % % Output, integer M, D, the month and day of the Julian calendar % on which Easter occurs. % if ( y <= 0 ) m = -1; d = -1; return end a = year_to_golden_number ( y ); a = a - 1; b = 22 + mod ( 225 - 11 * a, 30 ); s = b + mod ( 56 + 6 * y - floor ( y / 4 ) - b, 7 ); m = 3 + floor ( s / 32 ); % % Use wrapping to ensure that 1 <= D <= 31. % d = i4_wrap ( s, 1, 31 ); return end