When is Easter this year.

Discussion in 'The Commons' started by AnglicanAgnostic, Mar 24, 2022.

  1. ZachT

    ZachT Well-Known Member

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    It will always result in an integer. You get the remainder by dividing by 19. If you multiply the remainder by 19 it will return to an integer every time.
     
  2. AnglicanAgnostic

    AnglicanAgnostic Well-Known Member

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    You are right of course and even as I wrote it I thought it was wrong. I was going to correct myself but due to Murphies law I knew someone would correct me first. :D

    Perhaps Botolph's formula is better expressed as 2023/19=106+ 9/19 minus rounddown 2023/19 [ie 106]. The answer being just 9/19 and 9/19 x 19 is of course just 9.
     
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  3. ZachT

    ZachT Well-Known Member

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    Developer request to add a KaTeX or MathJax plugin to the forum so we can make reading these math equations bearable :laugh:.
     
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  4. Rexlion

    Rexlion Well-Known Member

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    Anglicans are practicing Bisextiles? What is the world coming to?? :halo:

    (I like math, but not that much.) :)
     
  5. Botolph

    Botolph Well-Known Member

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    Bisextile Years

    These are years where the number of days includes two sixes, as in 366, as against the more normative 365.
     
  6. Tiffy

    Tiffy Well-Known Member

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    Thats odd: My caclulator prog on my Mac gives the answer 106.473684210526316 as the answer to (2023/19)
    By subtracting 106 from 106.473684210526316 I get the remainder 0.473684210526316 and by multiplying that by 19 I get exactly 9 with no remainder.

    What's puzzling me is how dividing 0.473684210526 on your Casio gets the same result (= 9 with no remainder), as my Mac, which has three significant digits more in the remainder number than your Casio has.

    When I multiply 0.473684210526 (Your Casio result), by 19 on my Mac Calculator, I get 8.999999999994. Which you are quite right to assume is not an integer. Your Cassio must be cleverly rounding up (0.473684210526 x 19) to get the answer 9, because the answer should in fact be 8.999999999994.

    My guess is that it is just that although the digits display on your Casio is only 13 digits long, its internal calculating software can cope with the 3 extra digits the Casio can't display, so internally it actually performs the calculation, (0.473684210526316 x 19.0) and so gets an exact integer i.e 9.
     
    Last edited: Mar 30, 2022
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  7. Tiffy

    Tiffy Well-Known Member

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    Don't worry, there is absolutely nothing unnatural about being bissextile. It is naturally within the wide range of normal human understanding of mathematical and arithmetical behaviour. :laugh: Nothing here to get all worked up about.
    .
     
  8. Tiffy

    Tiffy Well-Known Member

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    ??? What's so special about EASTER Sunday that it should come exactly 3 days after Friday. All other Sundays seem to me to be only 2 days after Friday's over and done with. What's the other day between Friday and Easter Sunday called then, along with the normal Saturdays only, on every other weekend? :laugh:
    .​
     
    Last edited: Mar 30, 2022
  9. AnglicanAgnostic

    AnglicanAgnostic Well-Known Member

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    If you really want to know just ask rstrats and his questions about Matthew's 12:40 three days and three nights.
     
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  10. Tiffy

    Tiffy Well-Known Member

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    Oh Gosh! Don't get him started again, pleasssse. :laugh:
    .
     
  11. Rexlion

    Rexlion Well-Known Member

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    You are the Abbott to my Costello. :cheers: (You do know who Abbott & Costello were, don't you?)
     
  12. AnglicanAgnostic

    AnglicanAgnostic Well-Known Member

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    This number I actually got from Botolph's post#17. My calculator must process more numbers than it displays. I can enter the number ok but if I multiply it by 1000 or 100000 or whatever it displays only the first 10 digits.
    As an aside my slide rule will tell me that the sine of 1 second (1/3600 of a degree) is 0.000004845 (believe it or not) but my Casio says 0.000005 but if I multiply that by 1 million I can deduce the answer is 0.000004848137.
     
  13. Botolph

    Botolph Well-Known Member

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    I note that a great deal of time was devoted following the arrival of Augustan to Canterbury discussing and debating the correct date for Easter. It seems that there is nothing new under the sun.
     
  14. Mockingbird

    Mockingbird Member

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    That's right. The ecclesiastical moon is based on average lunations as tabulated in the 16th-century Prutenic tables, which were tabulated for Europe.

    The current cycle of Paschal full moons is:

    Year of cycle/Gregorian PFM (1900-2199)
    1 / April 14
    2 / April 3
    3 / March 23
    4 / April 11
    5 / March 31
    6 / April 18
    7 / April 8
    8 / March 28
    9 / April 16
    10 / April 5
    11 / March 25
    12 / April 13
    13 / April 2
    14 / March 22
    15 / April 10
    16 / March 30
    17 / April 17
    18 / April 7
    19 / March 27

    The current year, 2022, as other contributors to this thread have noted, is year 9, with a PFM on April 16.

    These dates hold good from 1900 to 2199, after which they will be replaced by another set of PFM dates that will hold good for a hundred years, then those will be replaced in turn. So any date between March 21 and April 18 can show up in a list of PFMs eventually.
     
  15. PDL

    PDL Well-Known Member Anglican

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    My (partial) understanding is what you said. It's the first full moon after 21st March and if the full moon occurs on a Sunday Easter is the following Sunday. I have also read on many occasions that the method of working this out is not determined by our current calendar and astronomical data. What I've never been able to ascertain is on what it's exactly based: hence my partial understanding.

    P.S. If you want to know when Easter is just pop into your local supermarket. They'll be advertising the date of Easter and selling Easter eggs as early as, well it feels like, just after Christmas.:D
     
  16. Mockingbird

    Mockingbird Member

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    It is based on a lunar calendar which itself is based on the average, not the true, moon.
     
  17. Mockingbird

    Mockingbird Member

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    Very funny.
     
  18. Mockingbird

    Mockingbird Member

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    This year Easter is in the middle of the moon's third week of phases, on the 18th day of the moon, so it will be after the full moon even in New Zealand.
     
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  19. CRfromQld

    CRfromQld Moderator Staff Member

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    The Full Moon would, I suppose, technically occur at the moment when the moon's orbit is furthest from the sun. This moment would be a different local time all around the Earth, and can be in different days. I'm not sure how this gets allocated to calendars but up until now I've never heard of the full moon being on different dates in different countries.

    It's something to think about, but not too much.
     
  20. ZachT

    ZachT Well-Known Member

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    If you read the full thread you'll find it happened during Easter last year!

    In fact every full moon will be on a different calendar day in at least one timezone. Despite there only being 24 hours in a day, there are 26 timezones (UTC -12 through to UTC +14). This is because Kiribati's capital is in UTC +12, and rather than having 3/4 of their country geographically in a different calendar day to most of the population, they just keep going into UTC +13 and UTC +14, even though technically those parts of their country cross over to the "negative hours" part of the globe.

    So even if the full moon occurs at midnight UTC-12 time, that's still 2am the next day on a few islands in the middle of the Pacific.
     
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