Frank's Humble Abode at frankosite2020.com .... formerly known as frankosport.com
The Perpetual Calendar: Other Facts and Information



1: The Current Actual Days Per Month Reckoning
January ... 31                      July ....... 31
February .. 28 (29 in leap year)    August ..... 31
March ..... 31                      September .. 30
April ..... 30                      October .... 31
May ....... 31                      November ... 30
June ...... 30                      December ... 31

Regular Year ... 365 days - 52 7-day weeks plus 1 day
Leap Year ...... 366 days - 52 7-day weeks plus 2 days
Halves - 181 (182) / 184
Quarters - 90 (91) / 91 / 92 / 92
Leap Year - February 29th

Leap Year is any year that is divisble by 4. The exception to this is that any century
year that is -NOT- divisible by 400 (1700, 1800, 1900, 2100, 2200, etc) will not be
Leap Year. Century Years that are divisible by 400 (1600, 2000, 2400, 2800, etc) will
be Leap Years.

In any 400-year period, there are 303 365-day regular years (110,595 days) and 97
366-day Leap Years (35,502 days). This makes for a total of 146,097 days (exactly
20,871 7-day weeks) during the 400-year period.

400-Year Periods - Saturday January 1st 1600 to Friday December 31st 1999
Saturday January 1st 2000 to Friday December 31st 2399


2: An Alternative Days Per Month Reckoning
| This version creates a 364-day Calendar (371 days for Leap Year)

    January, April, July and October ................ 30 days each. 1st day of each month is Monday
    February, May, August and November ....... 31 days each. 1st of each month is Wednesday
    March, June, September and December .... 30 days each. 1st day of each month is Saturday

    Regular Year - 364 days ... 52 7-day weeks     Leap Year - 371 days ... 53 7-day weeks
    Halves - 182 / 182 days Quarters - 91 / 91 / 91 / 91 days
    Each week begins on a Monday, ends on a Sunday -- No chance ever of a Friday the 13th !!

    Leap Year, 371 days long with a 7-day "Leap Week" between June 30th and July 1st, is any
    year that ends in "0" or "5", with the following exceptions ...

      (1) Any years ending in "25" or "75"

      (2) Any Century Years divisible by 400 (1600, 2000, 2400, 2800, etc.),
        which of course is the exact opposite of the actual Gregorian system.

    In any given 400-year period, there are 329 364-day regular years (119,756 days) and 71
    371-day Leap Years (26,341 days). This makes for a total of 146,097 days (exactly 20,871
    7-day weeks) during any given 400-year period.

    Remarkably, the figures of 146,097 days and 20,871 weeks are an -EXACT MATCH- to
    the days and weeks within any 400-year period of the Gregorian Calendar !!!

    Example of the Special 364/371-day calendar   (opens in a new window/tab)

    SPECIAL NOTE
    The author of this web-site (frankosite2020.com - where you are now) is not the only one who
    has proposed this particular method of 364/371-day calendar reckoning.

    See the Symmetry 010 Calendar and the Symmetry 454 Calendar for more details.


3: The 4000-Year Rule

It has been suggested by some observers, including the astronomer John Herschel (1792-1871), that a
better approximation to the length of the tropical year would be 365 969/4000 days = 365.24225 days.

This would dictate 969 leap years every 4000 years, rather than the 970 leap years currently mandated
by the Gregorian calendar. This could be achieved by not observing Leap Year and February 29th every
4,000 years -- 4000 A.D., 8000 A.D., 12000 A.D., 16000 A.D. and so on.

To date, this "4000-year rule" has not been officially adopted.



Frank's Humble Abode at frankosite2020.com .... formerly known as frankosport.com
The Perpetual Calendar: Other Facts and Information




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