Calculate Easter Dates

Anonymous — Wed, 09 Nov 2016 14:04:15 GMT

Hi!

Is there a way to calculate automatically Easter dates for every year (in past and in future)?

Thanks!

Re: Calculate Easter Dates

rwunderlich — Wed, 09 Nov 2016 15:59:16 GMT

It may be possible to build the calculation in the script. Or iIf you just need the actual dates, you can download them from a site on the web. Google "Easter dates" and find a suitable source.

-Rob

Re: Calculate Easter Dates

marcus_sommer — Wed, 09 Nov 2016 16:09:24 GMT

Take a look here: Master Calendar with movable holidays which includes a calculation of the easter dates.

- Marcus

Re: Calculate Easter Dates

amonjaras_c40 — Fri, 10 May 2024 15:26:28 GMT

Hello Marcus and everyone! The link to the Master Calendar with movable holidays is dead now. Can we find it somewhere else?

Thanks!

Re: Calculate Easter Dates

marcus_sommer — Mon, 13 May 2024 09:59:33 GMT

@Sue_Macaluso - please make my previous blog-postings accessible again. Many thanks.

Re: Calculate Easter Dates

HoS1 — Mon, 13 May 2024 10:04:05 GMT

http://www.oremus.org/liturgy/etc/ktf/app/easter.html

There's a calculation explained.

Re: Calculate Easter Dates

Gaël — Thu, 20 Feb 2025 15:09:20 GMT

While this thread is old, the main question remains. I implemented the algorithm described in http://www.oremus.org/liturgy/etc/ktf/app/easter.html below.
If your goal is to compute net working days, you could add indicators for weekends and public holidays in a Master Calendar, and compute the sum of these days between the dates of interest.

// Compute Easter Sunday. Apparently, QLik Sense does not provide this info. // // Useful links // https://www.oremus.org/liturgy/etc/ktf/app/easter.html // https://almanac.oremus.org/easter/computus/ // https://help.qlik.com/en-US/qlikview/April2020/Subsystems/Client/Content/QV_QlikView/Scripting/dollar-sign-expansion-using-parameters.htm // We refer to the year number as y (or $1), and use it to calculate the // g: Golden number Set GoldenNumber = '(Mod($1, 19) + 1)'; // s: solar correction // l: lunar correction Set SolarCorrection= 'Floor(($1-1600)/100) - Floor(($1-1600)/400)'; Set LunarCorrection = 'Floor(((Floor(($1-1400)/100))*8)/25)'; // p': Next we calculate the date of the Paschal full moon, that is, the full moon which Easter is the Sunday after. This is done in several stages. Set Paschal_uncorr = 'Mod(3 - 11*$(GoldenNumber($1)) + $(SolarCorrection($1)) - $(LunarCorrection($1)), 30)'; // p: Paschal full moon (as the number of days after 21st March) // apply a minor correction to get the exact date of the Paschal full moon (as the number of days after 21st March) Set Paschal = 'If($(Paschal_uncorr($1)) = 29 or ($(Paschal_uncorr($1)) = 28 and $(GoldenNumber($1)) > 11), $(Paschal_uncorr($1))-1, $(Paschal_uncorr($1)))'; // d: calculate the 'Dominical number' // Note that this is the number from which the Dominical letter is determined Set DominicalNumber = 'Mod($1 + Floor($1/4) - Floor($1/100) + Floor($1/400),7)'; // d': which is the date on which the first Sunday of the year falls Set FirstSunday = 'Mod(8-$(DominicalNumber($1)), 7)'; // p'': the first date in the year which falls on the same day of the week as the Paschal full moon. Set FirstDay = 'Mod(31 + 28 + 21 + $(Paschal($1)), 7)'; // x = difference between d' (the first Sunday in the year) and p'' (the day of the week when the Paschal full moon falls) // with minor correction so that x falls within the range 1-7 instead of 0-6 Set SundayDiff = '(Mod($(FirstSunday($1)) - $(FirstDay($1)) - 1, 7) + 1)'; // number of days Easter falls after 21st March: Set EasterOffset = '$(Paschal($1)) + $(SundayDiff($1))'; Set Easter = 'Date(MakeDate($1, 3, 21) + $(EasterOffset($1)))'; Let y = Year(Today()); Let g = $(GoldenNumber(Year(Today()))); Let s = $(SolarCorrection(Year(Today()))); Let l = $(LunarCorrection(Year(Today()))); Let p_prime = $(Paschal_uncorr(Year(Today()))); Let p = $(Paschal(Year(Today()))); Let d = $(DominicalNumber(Year(Today()))); Let d_prime = $(FirstSunday(Year(Today()))); Let p_dblprime = $(FirstDay(Year(Today()))); Let x = $(SundayDiff(Year(Today()))); Let e = $(EasterOffset(Year(Today()))); Let Easter_2024 = $(Easter(Year(Today())-1)); Let Easter_ThisYear = $(Easter(Year(Today()))); Let Easter_2026 = $(Easter(2026)); Let Easter_2027 = $(Easter(2027)); Let Easter_2028 = $(Easter(2028)); Let Easter_2029 = $(Easter(2029)); trace >>> Year = $(y); trace >>> GoldenNumber($(y)) = $(g); trace >>> SolarCorrection($(y)) = $(s); trace >>> LunarCorrection($(y)) = $(l); trace >>> Paschal_uncorr($(y)) = $(p_prime); trace >>> Paschal($(y)) = $(p); trace >>> DominicalNumber($(y)) = $(d); trace >>> FirstSunday($(y)) = $(d_prime); trace >>> FirstDay($(y)) = $(p_dblprime); trace >>> SundayDiff($(y)) = $(x); trace >>> EasterOffset($(y)) = $(e); trace >>> Easter(2024) = $(Easter_2024); trace >>> Easter($(y)) = $(Easter_ThisYear); trace >>> Easter(2026) = $(Easter_2026); trace >>> Easter(2027) = $(Easter_2027); trace >>> Easter(2028) = $(Easter_2028); trace >>> Easter(2029) = $(Easter_2029); Let y = NULL(); Let g = NULL(); Let s = NULL(); Let l = NULL(); Let p_prime = NULL(); Let p = NULL(); Let d = NULL(); Let d_prime = NULL(); Let p_dblprime = NULL(); Let x = NULL(); Let e = NULL(); Let Easter_2024 = NULL(); Let Easter_ThisYear = NULL(); Let Easter_2026 = NULL(); Let Easter_2027= NULL(); Let Easter_2028 = NULL(); Let Easter_2029 = NULL();

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