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The rule determining whether a year has 53 weeks, will be more complicated than a leap year rule, especially if the variation of the equinox and solstice dates is less than two weeks.
Incorrect. Gregorian-level accuracy can be achieved with this simple rule: Leap weeks are added in multiples of 5 except for multiples of 40 not divisible by 400.
Equal complexity to the Gregorian calendar's leap day rule.
The lnk goes to the CCC&T site, and lists leap weeks according to that calendar. This is wrong because different leap year rules were used to derive the list (CCC&T uses unspecified astronomical data - ISO 8601 is derived from the underlying gregorian year) and because the CCC&T calendar begins on Sunday rather than Monday, meaning that start dates cannot be matched.
What is the reason for renaming the article? I note that related links in the newly renamed article still refer to "Leap Week Calendar" rather than "Week Calendar". I see no compelling reason to have changed the name, but maybe I'm missing something. Victor Engel ( talk) 14:26, 31 March 2011 (UTC)
I agree. A calendar that uses a leap week is a leap week calendar, a calendar that uses a leap day is a leap day calendar, and a calendar that uses a leap month is a leap month calendar. One can equally well use a skip week, skip day, or skip month calendar with the same duration leap cycles, it doesn't change how many years are long vs. short. Leaps per Cycle = Years per Cycle minus Skips per Cycle. Kalendis ( talk) 21:09, 1 April 2011 (UTC)
One of the advantages is apparently "For leap week calendars without months, each date of the year can be completely specified with three data (week, weekday, year), instead of four (weekday, month, ordinal day, year)." Call me old fashioned, but I only need 3 pieces of data NOW to reference any day in any year. Day of month, month, and year. MrZoolook ( talk) 00:28, 14 January 2013 (UTC)
Says the article "Leap-year rules are usually more complicated than the Gregorian rule—except for the ISO Week Date, which follows the Gregorian calendar, having no leap-year rule of its own.".
What kind of exception is this? You have to figure out what day the Gregorian year starts on. To do that you have to use the Gregorian rule to figure out leap years but your not finished, you then have to figure out what day the Gregorian year would start on. It is a rule of its own, a very complicated rule.
There is, however, a simple rule which gives average years of a reasonable length (I don't know whether any notable proposal suggests it, though). We could switch the 4, 100 & 400 of the Gregorian with 5, 40 & 400. This rule is just as simple and gives a year just as long. Jimp 10:38, 19 March 2014 (UTC)
Because of tracking errors the frequency of centennial leap years will have to be reduced if the dates of the equinoxes and solstices are to be maintained. Tidal friction causes a progressive increase in the length of the day, the retardation in clock time compared to about 1820 being known as delta T.
If the present Gregorian calendar is left unaltered the dates of the equinoxes and solstices will continue to move backwards as they have done since it was first introduced in 1582. The calendar could be reconfigured so that the mean vernal equinox [1] never falls later than 1 PM Greenwich Mean Time on 19 March. The significance of this is that the astronomical equinox in turn falls no later than noon GMT on 21 March. This prevents Easter Sunday falling on the same day as the astronomical equinox anywhere in the world.
The trigger for the introduction of the Revised Gregorian calendar would be when the mean vernal equinox in a year giving remainder three on division by 400 was calculated to fall for the first time earlier than 1 PM (GMT) on 18 March. The preceding leap year would be cancelled. Thereafter all centennial years would normally be common, until the third year following was calculated to have a mean vernal equinox later than 1 PM (GMT) on 19 March, in which case the preceding leap year would be reinstated.
Extrapolating delta T forward, based on the average rate of increase over the past 27 centuries, [2] [3] [4] the tipping point will be reached in the year 8403, when the mean vernal equinox is calculated to fall at 3 AM (GMT) on 18 March, [5] conveniently very close to the year (AD 8599) when the Easter table in the Book of Common Prayer of the Church of England expires. [6] AD 8400 would be common, with the next two centennial leap years in AD 8800 and AD 9700. These dates are only provisional, since the future rate of increase of delta T cannot be predicted with complete certainty. Looking further ahead, when the mean tropical year drops below 365.24 days the minimum four-year interval between leap years will have to be extended.
Looking ahead millions of years, if there are still people around then, when the mean tropical year falls below 365 days, August would lose a day. Below 364 days, December would lose a day. Below 363 days, January would lose a day. Below 362 days, August would lose another day. Below 361 days, December would lose another day. Below 360 days, June would lose a day. Below 359 days, April would lose a day. Below 358 days, September would lose a day. Below 357 days, November would lose a day. Below 356 days, January would lose another day, thus restoring the lengths of the months to those of the Roman Republican calendar, which was replaced by the Julian, itself replaced by the Gregorian.
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This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
The rule determining whether a year has 53 weeks, will be more complicated than a leap year rule, especially if the variation of the equinox and solstice dates is less than two weeks.
Incorrect. Gregorian-level accuracy can be achieved with this simple rule: Leap weeks are added in multiples of 5 except for multiples of 40 not divisible by 400.
Equal complexity to the Gregorian calendar's leap day rule.
The lnk goes to the CCC&T site, and lists leap weeks according to that calendar. This is wrong because different leap year rules were used to derive the list (CCC&T uses unspecified astronomical data - ISO 8601 is derived from the underlying gregorian year) and because the CCC&T calendar begins on Sunday rather than Monday, meaning that start dates cannot be matched.
What is the reason for renaming the article? I note that related links in the newly renamed article still refer to "Leap Week Calendar" rather than "Week Calendar". I see no compelling reason to have changed the name, but maybe I'm missing something. Victor Engel ( talk) 14:26, 31 March 2011 (UTC)
I agree. A calendar that uses a leap week is a leap week calendar, a calendar that uses a leap day is a leap day calendar, and a calendar that uses a leap month is a leap month calendar. One can equally well use a skip week, skip day, or skip month calendar with the same duration leap cycles, it doesn't change how many years are long vs. short. Leaps per Cycle = Years per Cycle minus Skips per Cycle. Kalendis ( talk) 21:09, 1 April 2011 (UTC)
One of the advantages is apparently "For leap week calendars without months, each date of the year can be completely specified with three data (week, weekday, year), instead of four (weekday, month, ordinal day, year)." Call me old fashioned, but I only need 3 pieces of data NOW to reference any day in any year. Day of month, month, and year. MrZoolook ( talk) 00:28, 14 January 2013 (UTC)
Says the article "Leap-year rules are usually more complicated than the Gregorian rule—except for the ISO Week Date, which follows the Gregorian calendar, having no leap-year rule of its own.".
What kind of exception is this? You have to figure out what day the Gregorian year starts on. To do that you have to use the Gregorian rule to figure out leap years but your not finished, you then have to figure out what day the Gregorian year would start on. It is a rule of its own, a very complicated rule.
There is, however, a simple rule which gives average years of a reasonable length (I don't know whether any notable proposal suggests it, though). We could switch the 4, 100 & 400 of the Gregorian with 5, 40 & 400. This rule is just as simple and gives a year just as long. Jimp 10:38, 19 March 2014 (UTC)
Because of tracking errors the frequency of centennial leap years will have to be reduced if the dates of the equinoxes and solstices are to be maintained. Tidal friction causes a progressive increase in the length of the day, the retardation in clock time compared to about 1820 being known as delta T.
If the present Gregorian calendar is left unaltered the dates of the equinoxes and solstices will continue to move backwards as they have done since it was first introduced in 1582. The calendar could be reconfigured so that the mean vernal equinox [1] never falls later than 1 PM Greenwich Mean Time on 19 March. The significance of this is that the astronomical equinox in turn falls no later than noon GMT on 21 March. This prevents Easter Sunday falling on the same day as the astronomical equinox anywhere in the world.
The trigger for the introduction of the Revised Gregorian calendar would be when the mean vernal equinox in a year giving remainder three on division by 400 was calculated to fall for the first time earlier than 1 PM (GMT) on 18 March. The preceding leap year would be cancelled. Thereafter all centennial years would normally be common, until the third year following was calculated to have a mean vernal equinox later than 1 PM (GMT) on 19 March, in which case the preceding leap year would be reinstated.
Extrapolating delta T forward, based on the average rate of increase over the past 27 centuries, [2] [3] [4] the tipping point will be reached in the year 8403, when the mean vernal equinox is calculated to fall at 3 AM (GMT) on 18 March, [5] conveniently very close to the year (AD 8599) when the Easter table in the Book of Common Prayer of the Church of England expires. [6] AD 8400 would be common, with the next two centennial leap years in AD 8800 and AD 9700. These dates are only provisional, since the future rate of increase of delta T cannot be predicted with complete certainty. Looking further ahead, when the mean tropical year drops below 365.24 days the minimum four-year interval between leap years will have to be extended.
Looking ahead millions of years, if there are still people around then, when the mean tropical year falls below 365 days, August would lose a day. Below 364 days, December would lose a day. Below 363 days, January would lose a day. Below 362 days, August would lose another day. Below 361 days, December would lose another day. Below 360 days, June would lose a day. Below 359 days, April would lose a day. Below 358 days, September would lose a day. Below 357 days, November would lose a day. Below 356 days, January would lose another day, thus restoring the lengths of the months to those of the Roman Republican calendar, which was replaced by the Julian, itself replaced by the Gregorian.
{{
cite book}}
: CS1 maint: location missing publisher (
link)
{{
cite book}}
: CS1 maint: location missing publisher (
link)