Solar cycle (calendar)

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The solar cycle is a 28-year cycle of the Julian calendar with respect to the week. It occurs because leap years occur every 4 years and there are 7 possible days to start a leap year, making a 28 year sequence.

This cycle also occurs in the Gregorian calendar, but it is interrupted by years such as 1700, 1800, 1900 and 2100, which are divisible by four but which are not leap years. This interruption has the effect of skipping 16 years of the solar cycle between February 28 and March 1. Because the Gregorian cycle of 400 years has exactly 146,097 days, i.e. exactly 20,871 weeks, one can say that the Gregorian so-called solar cycle lasts 400 years.

Calendar years are usually marked by Dominical letters indicating the first Sunday in a new year, thus the term solar cycle can also refer to a repeating sequence of Dominical letters.

Unless a year is not a leap year due to Gregorian exceptions, a sequence of calendars is reused every 28 years.

The name solar cycle comes from Sunday, the traditional first day of the week.

Example[edit]

Julian calendar[edit]

The dominical letter in the Julian calendar depends only on the remainder when the year is divided by 28.

Remainder Dominical letter
0 DC
1 B
2 A
3 G
4 FE
5 D
6 C
7 B
8 AG
9 F
10 E
11 D
12 CB
13 A
14 G
15 F
16 ED
17 C
18 B
19 A
20 GF
21 E
22 D
23 C
24 BA
25 G
26 F
27 E

Gregorian calendar[edit]

The years 1700, 1800, and 1900 were not leap years and do not fit in the tables below.

1583–1699[edit]

1583–1610 1611–1638 1639–1666 1667–1694 1695–1699 Dominical letter
1583 1611 1639 1667 1695 B
1584 1612 1640 1668 1696 AG
1585 1613 1641 1669 1697 F
1586 1614 1642 1670 1698 E
1587 1615 1643 1671 1699 D
1588 1616 1644 1672 CB
1589 1617 1645 1673 A
1590 1618 1646 1674 G
1591 1619 1647 1675 F
1592 1620 1648 1676 ED
1593 1621 1649 1677 C
1594 1622 1650 1678 B
1595 1623 1651 1679 A
1596 1624 1652 1680 GF
1597 1625 1653 1681 E
1598 1626 1654 1682 D
1599 1627 1655 1683 C
1600 1628 1656 1684 BA
1601 1629 1657 1685 G
1602 1630 1658 1686 F
1603 1631 1659 1687 E
1604 1632 1660 1688 DC
1605 1633 1661 1689 B
1606 1634 1662 1690 A
1607 1635 1663 1691 G
1608 1636 1664 1692 FE
1609 1637 1665 1693 D
1610 1638 1666 1694 C

1701–1799[edit]

1701–1728 1729–1756 1757–1784 1785–1799 Dominical letter
1701 1729 1757 1785 B
1702 1730 1758 1786 A
1703 1731 1759 1787 G
1704 1732 1760 1788 FE
1705 1733 1761 1789 D
1706 1734 1762 1790 C
1707 1735 1763 1791 B
1708 1736 1764 1792 AG
1709 1737 1765 1793 F
1710 1738 1766 1794 E
1711 1739 1767 1795 D
1712 1740 1768 1796 CB
1713 1741 1769 1797 A
1714 1742 1770 1798 G
1715 1743 1771 1799 F
1716 1744 1772 ED
1717 1745 1773 C
1718 1746 1774 B
1719 1747 1775 A
1720 1748 1776 GF
1721 1749 1777 E
1722 1750 1778 D
1723 1751 1779 C
1724 1752 1780 BA
1725 1753 1781 G
1726 1754 1782 F
1727 1755 1783 E
1728 1756 1784 DC

1801–1899[edit]

1801–1828 1829–1856 1857–1884 1885–1899 Dominical letter
1801 1829 1857 1885 D
1802 1830 1858 1886 C
1803 1831 1859 1887 B
1804 1832 1860 1888 AG
1805 1833 1861 1889 F
1806 1834 1862 1890 E
1807 1835 1863 1891 D
1808 1836 1864 1892 CB
1809 1837 1865 1893 A
1810 1838 1866 1894 G
1811 1839 1867 1895 F
1812 1840 1868 1896 ED
1813 1841 1869 1897 C
1814 1842 1870 1898 B
1815 1843 1871 1899 A
1816 1844 1872 GF
1817 1845 1873 E
1818 1846 1874 D
1819 1847 1875 C
1820 1848 1876 BA
1821 1849 1877 G
1822 1850 1878 F
1823 1851 1879 E
1824 1852 1880 DC
1825 1853 1881 B
1826 1854 1882 A
1827 1855 1883 G
1828 1856 1884 FE

1901–2099[edit]

1901–1928 1929–1956 1957–1984 1985–2012 2013–2040 2041–2068 2069–2096 2097–2099 Dominical letter
1901 1929 1957 1985 2013 2041 2069 2097 F
1902 1930 1958 1986 2014 2042 2070 2098 E
1903 1931 1959 1987 2015 2043 2071 2099 D
1904 1932 1960 1988 2016 2044 2072 CB
1905 1933 1961 1989 2017 2045 2073 A
1906 1934 1962 1990 2018 2046 2074 G
1907 1935 1963 1991 2019 2047 2075 F
1908 1936 1964 1992 2020 2048 2076 ED
1909 1937 1965 1993 2021 2049 2077 C
1910 1938 1966 1994 2022 2050 2078 B
1911 1939 1967 1995 2023 2051 2079 A
1912 1940 1968 1996 2024 2052 2080 GF
1913 1941 1969 1997 2025 2053 2081 E
1914 1942 1970 1998 2026 2054 2082 D
1915 1943 1971 1999 2027 2055 2083 C
1916 1944 1972 2000 2028 2056 2084 BA
1917 1945 1973 2001 2029 2057 2085 G
1918 1946 1974 2002 2030 2058 2086 F
1919 1947 1975 2003 2031 2059 2087 E
1920 1948 1976 2004 2032 2060 2088 DC
1921 1949 1977 2005 2033 2061 2089 B
1922 1950 1978 2006 2034 2062 2090 A
1923 1951 1979 2007 2035 2063 2091 G
1924 1952 1980 2008 2036 2064 2092 FE
1925 1953 1981 2009 2037 2065 2093 D
1926 1954 1982 2010 2038 2066 2094 C
1927 1955 1983 2011 2039 2067 2095 B
1928 1956 1984 2012 2040 2068 2096 AG

See also[edit]