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#21
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The perpetual calendar
On Feb 19, 5:14*am, Ruud Harmsen wrote:
Fri, 19 Feb 2010 10:34:10 +0100: James Hogg : in sci.lang: What could be simpler? The Jewish calendar. the Jewish Calendar has a complicated algorithm, IIRC refined by the famous 18th cent. mathematician Euler. the complications are due to making sure that certain holidays do not fall on certain days. http://en.wikipedia.org/wiki/Hebrew_Calendar Hebrew calendar .... Special holiday rules Adjustments are made to ensure certain holy days and festivals do or do not fall on certain days of the week. Yom Kippur Adjustments are made to ensure that Yom Kippur, on which no work can be done, does not fall on Friday (the day prior to the Sabbath) to avoid having Yom Kippur's restrictions still going on at the start of Sabbath, or on Sunday (the day after Shabbat) to avoid having the Shabbat restrictions still going on at the start of Yom Kippur. The Rosh Hashanah postponement rules are the mechanism used to make the adjustments. As Yom Kippur falls on Tishrei 10, and Rosh Hashanah falls on the 1st, the adjustment is made so that Rosh Hashanah does not fall on a Wednesday or Friday. To ensure that Yom Kippur does not directly precede or follow Shabbat, and that Hoshana Rabbah is not on a Shabbat, in which case certain ceremonies would be lost for a year, the first day of Rosh Hashanah may only occur on Mondays, Tuesdays, Thursdays, and Saturdays (the "four gates"). Adjustments are made to ensure that Rosh Hashanah does not fall on the other three days. To achieve that result the year may be made into a short (chaser) year (both Kislev and Cheshvan have 29 days) or full (maleh) year (both Kislev and Cheshvan have 30 days). (see table) The day of the week on which Rosh Hashanah falls in any given year will also be the day on which Sukkot and Shmini Atzeret will occur. -- Ruud Harmsen,http://rudhar.com |
#22
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The perpetual calendar
Yusuf B Gursey wrote (19-02-2010 15:35):
the Orthodox (Eastern) churches have a slightly different system. dunno exactly what it is. Afaik the system is the same, it's March 21 that is different. |
#23
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The perpetual calendar
John Atkinson :
Halmyre wrote: I just wish they'd settle on a date for Easter and be done with it. But, the whole point of Easter is that it has a full moon! A full-*ish* moon, actually. The definitions of the equinox and full moon used when determining Easter are rather different from the real definitions used by astronomers, which would actually give rise to different (perhaps several weeks different) Easter dates depending on one's longitude. But I thought that for most people the whole point of Easter is that they get time off work. -- Mike Barnes Cheshire, England |
#24
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The perpetual calendar
Evan Kirshenbaum wrote:
"Peter T. Daniels" writes: On Feb 19, 4:34 am, James Hogg wrote: My Book of Common Prayer makes things easy by pointing out that "the moon referred to in the definition of Easter Day is not the actual moon of the heavens, but the Calendar Moon, or Moon of the Lunar Cycle, which is counted as full on its fourteenth day, reckoned from the day of the Calendar New Moon inclusive." Also, in a Bissextile Year "the number of Sundays after Epiphany will be the same, as if Easter Day had fallen one day later than it really does." Which is why Easter and Passover rarely coincide -- we happen to have had a spate of coincidence in recent years, but that'll soon be over. Which years were those? I had thought that the current Easter rules made it impossible for it to fall on the 15th of Nissan. I understood that it is not actually impossible but that the coincidence is very rare. ISTR it happened at some point in the early 1980s. Of course, Passover week quite often covers Good Friday and Easter Sunday - it does this year. -- Laura (emulate St. George for email) |
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The perpetual calendar
On Feb 19, 11:52*am, Evan Kirshenbaum wrote:
"Peter T. Daniels" writes: On Feb 19, 4:34 am, James Hogg wrote: My Book of Common Prayer makes things easy by pointing out that "the moon referred to in the definition of Easter Day is not the actual moon of the heavens, but the Calendar Moon, or Moon of the Lunar Cycle, which is counted as full on its fourteenth day, reckoned from the day of the Calendar New Moon inclusive." Also, in a Bissextile Year "the number of Sundays after Epiphany will be the same, as if Easter Day had fallen one day later than it really does." Which is why Easter and Passover rarely coincide -- we happen to have had a spate of coincidence in recent years, but that'll soon be over. Which years were those? *I had thought that the current Easter rules made it impossible for it to fall on the 15th of Nissan. I think it was two years ago that the first night of Passover was on Holy Thursday (or vice versa), which precisely reproduced the historical occasion. Why would the "current" Easter rules have such a restriction? There's certainly nothing about it in the several pages of small type in the front of the Book of Common Prayer (1928), which I read plenty of times while waiting for Morning Prayer to end. |
#26
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The perpetual calendar
On Feb 19, 10:30*am, Yusuf B Gursey wrote:
On Feb 19, 8:24*am, "Peter T. Daniels" wrote: On Feb 19, 4:34*am, James Hogg wrote: John Atkinson wrote: Halmyre wrote: On 19 Feb, 04:58, "Ray O'Hara" wrote: "Andrew Usher" wrote in message ... Owing to the inconveniences which attend the shifting of the calendar, and attempting in passing to create a more perfect Church calendar, I say the following: 1. That Christmas day should be fixed to a Sunday, and this should be the Sunday between Dec. 21 and 27, and that in all civilised countries the Monday should be considered a holiday, or the Saturday if not normally. 2. That similarly Easter day should be fixed to the Sunday which is 15 weeks following Christmas. 3. That the leap year rule be changed to have a leap year occur every fourth save that it be delayed when the leap year would start on a Thursday, and that this gives 7 leap years in every 29, which is near enough. 4. That the perpetual calendar can be made, by considering the first day of the year of weeks to occur on the Sunday after the Assumption, and if this is the first possible calendar day, it is called week 1, and otherwise week 2, and every year runs through week 53. And this calendar ensures that everything can be fixed to a day of a certain week, in particular the American Thanksgiving must be made 31 days before Christmas. 6. This is surely the best possible arrangement that can be made, without disturbing the cycle of weeks or that of calendar days inherited from the Romans. Andrew Usher The calendar has several sources, not just the Rome and the onewe habe in fine as it is I just wish they'd settle on a date for Easter and be done with it.. But, the whole point of Easter is that it has a full moon! *You might as well scrap the whole thing otherwise. *Or are you suggesting that we only take holidays at Easter every four years or so, when your “settled” date just happens to correspond with the right lunar phase? My Book of Common Prayer makes things easy by pointing out that "the moon referred to in the definition of Easter Day is not the actual moon of the heavens, but the Calendar Moon, or Moon of the Lunar Cycle, which is counted as full on its fourteenth day, reckoned from the day of the Calendar New Moon inclusive." Also, in a Bissextile Year "the number of Sundays after Epiphany will be the same, as if Easter Day had fallen one day later than it really does." Which is why Easter and Passover rarely coincide -- we happen to have had a spate of coincidence in recent years, but that'll soon be over. What could be simpler? The Muslim calendar -- no intercalated months, and no connection with the solar year. So Ramadan drifts through the seasons. Ramadan is celebrated according to the actual siting of the crescent, not the (various) algorithms used for civil purposes, though I think some "cheat" by using the algorithms (there are a couple most frequently used). last time in Iraq the Shia and the Sunni observed it at different dates. so it is rather complicated.- They _do_ publish calendars that cover more than the next 29 1/2 days, don't they? Such information _can_ be calculated (and was calculated 3000 years ago in Mesopotamia), and varies from site to site depending on latitude, weather, and surrounding terrain (i.e., where's the horizon?). |
#27
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The perpetual calendar
On Feb 19, 12:10*pm, "Peter T. Daniels" wrote:
On Feb 19, 10:30*am, Yusuf B Gursey wrote: On Feb 19, 8:24*am, "Peter T. Daniels" wrote: On Feb 19, 4:34*am, James Hogg wrote: John Atkinson wrote: Halmyre wrote: On 19 Feb, 04:58, "Ray O'Hara" wrote: "Andrew Usher" wrote in message ... Owing to the inconveniences which attend the shifting of the calendar, and attempting in passing to create a more perfect Church calendar, I say the following: 1. That Christmas day should be fixed to a Sunday, and this should be the Sunday between Dec. 21 and 27, and that in all civilised countries the Monday should be considered a holiday, or the Saturday if not normally. 2. That similarly Easter day should be fixed to the Sunday which is 15 weeks following Christmas. 3. That the leap year rule be changed to have a leap year occur every fourth save that it be delayed when the leap year would start on a Thursday, and that this gives 7 leap years in every 29, which is near enough. 4. That the perpetual calendar can be made, by considering the first day of the year of weeks to occur on the Sunday after the Assumption, and if this is the first possible calendar day, it is called week 1, and otherwise week 2, and every year runs through week 53. And this calendar ensures that everything can be fixed to a day of a certain week, in particular the American Thanksgiving must be made 31 days before Christmas. 6. This is surely the best possible arrangement that can be made, without disturbing the cycle of weeks or that of calendar days inherited from the Romans. Andrew Usher The calendar has several sources, not just the Rome and the onewe habe in fine as it is I just wish they'd settle on a date for Easter and be done with it. But, the whole point of Easter is that it has a full moon! *You might as well scrap the whole thing otherwise. *Or are you suggesting that we only take holidays at Easter every four years or so, when your “settled” date just happens to correspond with the right lunar phase? My Book of Common Prayer makes things easy by pointing out that "the moon referred to in the definition of Easter Day is not the actual moon of the heavens, but the Calendar Moon, or Moon of the Lunar Cycle, which is counted as full on its fourteenth day, reckoned from the day of the Calendar New Moon inclusive." Also, in a Bissextile Year "the number of Sundays after Epiphany will be the same, as if Easter Day had fallen one day later than it really does." Which is why Easter and Passover rarely coincide -- we happen to have had a spate of coincidence in recent years, but that'll soon be over. What could be simpler? The Muslim calendar -- no intercalated months, and no connection with the solar year. So Ramadan drifts through the seasons. Ramadan is celebrated according to the actual siting of the crescent, not the (various) algorithms used for civil purposes, though I think some "cheat" by using the algorithms (there are a couple most frequently used). last time in Iraq the Shia and the Sunni observed it at different dates. so it is rather complicated.- They _do_ publish calendars that cover more than the next 29 1/2 days, don't they? Such information _can_ be calculated (and was calculated some allow calculation, but conservatives wait for a fatwa from the religious authorities to commence Ramadan, and this is the practice in many muslim countries. as I said before, in Iraq this resulted in the Shia and the Sunni observing Ramadan with a days difference.for other religious days, the algorithm may be used, but there are several versions of that, some being more common than others. 3000 years ago in Mesopotamia), and varies from site to site depending on latitude, weather, and surrounding terrain (i.e., where's the horizon?). |
#28
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The perpetual calendar
On Feb 19, 10:59*am, António Marques wrote:
Yusuf B Gursey wrote (19-02-2010 15:35): the Orthodox (Eastern) churches have a slightly different system. dunno exactly what it is. Afaik the system is the same, it's March 21 that is different. but for the Orthodox, the Gregorian calendar has been accepted for other holidays. the Monophysites (Copts, Armenians, Jacobite Syrians) observe Christmas at a different date for other reasons. |
#29
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The perpetual calendar
On 19 Feb, 09:12, John Atkinson wrote:
Halmyre wrote: On 19 Feb, 04:58, "Ray O'Hara" wrote: "Andrew Usher" wrote in message .... Owing to the inconveniences which attend the shifting of the calendar, and attempting in passing to create a more perfect Church calendar, I say the following: 1. That Christmas day should be fixed to a Sunday, and this should be the Sunday between Dec. 21 and 27, and that in all civilised countries the Monday should be considered a holiday, or the Saturday if not normally. 2. That similarly Easter day should be fixed to the Sunday which is 15 weeks following Christmas. 3. That the leap year rule be changed to have a leap year occur every fourth save that it be delayed when the leap year would start on a Thursday, and that this gives 7 leap years in every 29, which is near enough. 4. That the perpetual calendar can be made, by considering the first day of the year of weeks to occur on the Sunday after the Assumption, and if this is the first possible calendar day, it is called week 1, and otherwise week 2, and every year runs through week 53. And this calendar ensures that everything can be fixed to a day of a certain week, in particular the American Thanksgiving must be made 31 days before Christmas. 6. This is surely the best possible arrangement that can be made, without disturbing the cycle of weeks or that of calendar days inherited from the Romans. Andrew Usher The calendar has several sources, not just the Rome and the onewe habe in fine as it is I just wish they'd settle on a date for Easter and be done with it. But, the whole point of Easter is that it has a full moon! *You might as well scrap the whole thing otherwise. *Or are you suggesting that we only take holidays at Easter every four years or so, when your “settled” date just happens to correspond with the right lunar phase? We don't have Christmas only when there's a bright star in the east. It's like saying "I was born on a Wednesday, so I'll only celebrate my birthday when it falls on a Wednesday". -- Halmyre |
#30
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The perpetual calendar
Halmyre wrote:
On 19 Feb, 09:12, John Atkinson wrote: Halmyre wrote: On 19 Feb, 04:58, "Ray O'Hara" wrote: "Andrew Usher" wrote in message ... Owing to the inconveniences which attend the shifting of the calendar, and attempting in passing to create a more perfect Church calendar, I say the following: 1. That Christmas day should be fixed to a Sunday, and this should be the Sunday between Dec. 21 and 27, and that in all civilised countries the Monday should be considered a holiday, or the Saturday if not normally. 2. That similarly Easter day should be fixed to the Sunday which is 15 weeks following Christmas. 3. That the leap year rule be changed to have a leap year occur every fourth save that it be delayed when the leap year would start on a Thursday, and that this gives 7 leap years in every 29, which is near enough. 4. That the perpetual calendar can be made, by considering the first day of the year of weeks to occur on the Sunday after the Assumption, and if this is the first possible calendar day, it is called week 1, and otherwise week 2, and every year runs through week 53. And this calendar ensures that everything can be fixed to a day of a certain week, in particular the American Thanksgiving must be made 31 days before Christmas. 6. This is surely the best possible arrangement that can be made, without disturbing the cycle of weeks or that of calendar days inherited from the Romans. Andrew Usher The calendar has several sources, not just the Rome and the onewe habe in fine as it is I just wish they'd settle on a date for Easter and be done with it. But, the whole point of Easter is that it has a full moon! You might as well scrap the whole thing otherwise. Or are you suggesting that we only take holidays at Easter every four years or so, when your “settled” date just happens to correspond with the right lunar phase? We don't have Christmas only when there's a bright star in the east. It's like saying "I was born on a Wednesday, so I'll only celebrate my birthday when it falls on a Wednesday". -- Halmyre I suppose it all comes down to how much predictability each person likes. Some people like all their holidays to come at the same time each year, and others are happy to put up with Easter, for example, coming late some years because other years it comes nice and early, which makes a much-needed break in a long winter. I never did consider Easter to be necessarily a spring holiday, myself. Of course, people living in places where they already have public holidays in all three of the dreary months of January, February and March wouldn't greet an early Easter with as much enthusiasm as I do. And I know Easter doesn't occur in January or February, but they seem much longer than they are when Easter comes in the latter part of April; and slightly shorter than they are when I have a March Easter to look forward to. I want an official long holiday weekend in every single month, no exceptions. -- Cheryl |
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