Dee-Cecil Calendar and Simon Cassidy's Epacts

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Dee-Cecil Calendar and Simon Cassidy's Epacts

Walter J Ziobro
Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.

-Walter Ziobro



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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Amos Shapir-2
Hi Walter and Calendar people,

I don't think there's any chance of making the Church adopt any alternative way of computing the vernal equinox.  Keep in mind that the very purpose of the gregorian reform was to make the vernal equinox fall on a fixed date.

The only way to improve the Easter computus would require fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle.

On Mon, Jul 20, 2015 at 5:56 AM, Walter J Ziobro <[hidden email]> wrote:
Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.

-Walter Ziobro






--
Amos Shapir
 
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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Karl Palmen
In reply to this post by Walter J Ziobro

Dear Walter and Calendar People

 

There remains one outstanding issue, which makes the first proposal incomplete.

 

This is how the paschal full moon is determined by the epact.

 

The way used for the Gregorian calendar is complicated, because it requires

(1)    Easter to fall in a range of 35 days rather than 36 days that would naturally occur with a 7-day week and an epact range of 3

(2)    No two years in the same 19-year cycle with no correction within it can have the same date for the paschal full moon.

 

It could be rejected by Eastern churches. I’m not sure that they use epacts at all, they may simply use a look up table for the paschal full moon of a year of a given golden number.

If the 19-year cycle were corrected by modifying golden numbers rather than epacts, this same lookup table can be continued to be used. It automatically ensures a 35-day range for Easter.

The disadvantage is higher jitter from less frequent correction of the 19-year cycle.

 

The second proposal does address this issue and offers two alternatives. Both confine Easter to 35 days. The first is the Gregorian epact of days table, which I think would be rejected and the second is simpler for determining Easter, but always gives the same paschal full moon day (of April 18) for years of epact 24 and 25. It is possible that such years may occur near each other (how near, needs to be determined). 

 

Karl

 

15(02(04

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Walter J Ziobro
Sent: 20 July 2015 03:56
To: [hidden email]
Subject: Dee-Cecil Calendar and Simon Cassidy's Epacts

 

Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.

-Walter Ziobro


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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Sepp Rothwangl
Dear Calndr-people,

may I ask some principle things. and ask for thinking outside the box (of already existing calendars)

if thinking of new timekeeping:

1. what are not necessary components of a new timekeeping? what can omitted, what is not decisive, and so on …

…. which periods?

…. which components?

…. which dimensions?

…. what dates?

…. what determinations

…. what is decisive

…. which science

…. which religion, weltanschauung, doctrin, system

…..what else

…..


2. what are necessary (essential) components of a new timekeeping? What is decisive, essential, indispensable and so on…

please chose here anything you see as necessary, essential decisive and so on ….

….


BUT: please think out of the box!



Sepp Rothwangl, CEP -240.938

Am 20.07.2015 um 14:01 schrieb Karl Palmen <[hidden email]>:

Dear Walter and Calendar People
 
There remains one outstanding issue, which makes the first proposal incomplete.
 
This is how the paschal full moon is determined by the epact.
 
The way used for the Gregorian calendar is complicated, because it requires
(1)    Easter to fall in a range of 35 days rather than 36 days that would naturally occur with a 7-day week and an epact range of 3
(2)    No two years in the same 19-year cycle with no correction within it can have the same date for the paschal full moon.
 
It could be rejected by Eastern churches. I’m not sure that they use epacts at all, they may simply use a look up table for the paschal full moon of a year of a given golden number.
If the 19-year cycle were corrected by modifying golden numbers rather than epacts, this same lookup table can be continued to be used. It automatically ensures a 35-day range for Easter.
The disadvantage is higher jitter from less frequent correction of the 19-year cycle.
 
The second proposal does address this issue and offers two alternatives. Both confine Easter to 35 days. The first is the Gregorian epact of days table, which I think would be rejected and the second is simpler for determining Easter, but always gives the same paschal full moon day (of April 18) for years of epact 24 and 25. It is possible that such years may occur near each other (how near, needs to be determined). 
 
Karl
 
15(02(04
 
From: East Carolina University Calendar discussion List [[hidden email]] On Behalf Of Walter J Ziobro
Sent: 20 July 2015 03:56
To: [hidden email]
Subject: Dee-Cecil Calendar and Simon Cassidy's Epacts
 

Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:     

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.

-Walter Ziobro


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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Walter J Ziobro
In reply to this post by Amos Shapir-2
Dear Amos:

Well if the Christian churches are fixated on a specific date for the Ecclesiastical Vernal Equinox then their best option is to adopt the Dee-Cecil Calendar outright because the astronomical northward equinox will occur most often on March 21 for many centuries.

Walter Ziobro

Sent from my iPhone

On Jul 20, 2015, at 2:30 AM, Amos Shapir <[hidden email]> wrote:

Hi Walter and Calendar people,

I don't think there's any chance of making the Church adopt any alternative way of computing the vernal equinox.  Keep in mind that the very purpose of the gregorian reform was to make the vernal equinox fall on a fixed date.

The only way to improve the Easter computus would require fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle.

On Mon, Jul 20, 2015 at 5:56 AM, Walter J Ziobro <[hidden email]> wrote:
Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.

-Walter Ziobro






--
Amos Shapir
 
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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Walter J Ziobro
In reply to this post by Karl Palmen
Dear Karl:

I believe that there are epacts with the Julian lunar calendar, but they are rarely referred to because they are invariable with respect to each Golden Number.

Walter Ziobro


Sent from my iPhone

On Jul 20, 2015, at 8:01 AM, Karl Palmen <[hidden email]> wrote:

Dear Walter and Calendar People

 

There remains one outstanding issue, which makes the first proposal incomplete.

 

This is how the paschal full moon is determined by the epact.

 

The way used for the Gregorian calendar is complicated, because it requires

(1)    Easter to fall in a range of 35 days rather than 36 days that would naturally occur with a 7-day week and an epact range of 3

(2)    No two years in the same 19-year cycle with no correction within it can have the same date for the paschal full moon.

 

It could be rejected by Eastern churches. I’m not sure that they use epacts at all, they may simply use a look up table for the paschal full moon of a year of a given golden number.

If the 19-year cycle were corrected by modifying golden numbers rather than epacts, this same lookup table can be continued to be used. It automatically ensures a 35-day range for Easter.

The disadvantage is higher jitter from less frequent correction of the 19-year cycle.

 

The second proposal does address this issue and offers two alternatives. Both confine Easter to 35 days. The first is the Gregorian epact of days table, which I think would be rejected and the second is simpler for determining Easter, but always gives the same paschal full moon day (of April 18) for years of epact 24 and 25. It is possible that such years may occur near each other (how near, needs to be determined). 

 

Karl

 

15(02(04

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Walter J Ziobro
Sent: 20 July 2015 03:56
To: [hidden email]
Subject: Dee-Cecil Calendar and Simon Cassidy's Epacts

 

Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.

-Walter Ziobro


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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Karl Palmen
In reply to this post by Amos Shapir-2

Dear Amos, Walter and Calendar People

 

I looked back at some old notes and wonder what Amos meant by

fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle

 

It could mean fixing Easter date to something like the 2nd Sunday in April.

It could mean making Easter repeat on a 400-year cycle.

In neither case would Easter be lunar.

 

Perhaps it just means fixing the equinox date to Gregorian 21 March.

Actually I think the underlying issue is what day do we count the epacts relative to.  The number of days that the paschal full moon occurs after the ecclesiastical equinox day is determined in a simple manner from the epact. I think Walter wants to preserve that, but vary the ecclesiastical equinox date so that it jitters less. Then a method such as Simon Cassidy’s Moonkey epacts could be applied.

 

If we both fix the ecclesiastical epact date and preserve the simple relationship between the number of days that the paschal full moon occurs after the ecclesiastical equinox day and the epact, then the choice of good epact rules available is seriously constrained. This arises from the jitter of the Gregorian calendar of 2.1975 days, we don’t want all the jitter to be transferred to the Paschal full moon. One way of reducing the transfer of jitter is to have every correction of the 19-year cycle at a year ending in 00, which include the dropped leap years. Better still, decrement the epact by 1 at every dropped leap year (solar equation) and increment by 1 once every 300 or 400 years (lunar equation). This is what the Gregorian computus does.

 

The Gregorian computus corrects the 19-year cycle by simply decrementing or incrementing the epacts by 1. One could also correct by changing the Golden Number of the Saltus Lunae.  This offers finer control of 1/570 month instead of 1/30 month and allows the Easter days to follow a shorter cycle such as the 18,000-year cycle.

 

Karl

 

16(07(25

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Amos Shapir
Sent: 20 July 2015 07:31
To: [hidden email]
Subject: Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

 

Hi Walter and Calendar people,

I don't think there's any chance of making the Church adopt any alternative way of computing the vernal equinox.  Keep in mind that the very purpose of the gregorian reform was to make the vernal equinox fall on a fixed date.

The only way to improve the Easter computus would require fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle.

 

On Mon, Jul 20, 2015 at 5:56 AM, Walter J Ziobro <[hidden email]> wrote:

Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.


-Walter Ziobro





--

Amos Shapir

 

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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Walter J Ziobro
Dear Karl:

Your post reminded me of a thought that have had, for which I cannot think of any answer:

Is there any record of when Dee and Cecil  proposed their calendars with the 33 year leap day rule, whether they themselves proposed how Easter should be determined by their calendars?   It seems from what I have seen that Simon Cassidy was actually the first person to devise a lunar equation rule for any 33 year calendar.

-Walter Ziobro



-----Original Message-----
From: Karl Palmen <[hidden email]>
To: CALNDR-L <[hidden email]>
Sent: Wed, Mar 22, 2017 9:04 am
Subject: Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Dear Amos, Walter and Calendar People
 
I looked back at some old notes and wonder what Amos meant by
fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle
 
It could mean fixing Easter date to something like the 2nd Sunday in April.
It could mean making Easter repeat on a 400-year cycle.
In neither case would Easter be lunar.
 
Perhaps it just means fixing the equinox date to Gregorian 21 March.
Actually I think the underlying issue is what day do we count the epacts relative to.  The number of days that the paschal full moon occurs after the ecclesiastical equinox day is determined in a simple manner from the epact. I think Walter wants to preserve that, but vary the ecclesiastical equinox date so that it jitters less. Then a method such as Simon Cassidy’s Moonkey epacts could be applied.
 
If we both fix the ecclesiastical epact date and preserve the simple relationship between the number of days that the paschal full moon occurs after the ecclesiastical equinox day and the epact, then the choice of good epact rules available is seriously constrained. This arises from the jitter of the Gregorian calendar of 2.1975 days, we don’t want all the jitter to be transferred to the Paschal full moon. One way of reducing the transfer of jitter is to have every correction of the 19-year cycle at a year ending in 00, which include the dropped leap years. Better still, decrement the epact by 1 at every dropped leap year (solar equation) and increment by 1 once every 300 or 400 years (lunar equation). This is what the Gregorian computus does.
 
The Gregorian computus corrects the 19-year cycle by simply decrementing or incrementing the epacts by 1. One could also correct by changing the Golden Number of the Saltus Lunae.  This offers finer control of 1/570 month instead of 1/30 month and allows the Easter days to follow a shorter cycle such as the 18,000-year cycle.
 
Karl
 
16(07(25
 
From: East Carolina University Calendar discussion List [[hidden email]] On Behalf Of Amos Shapir
Sent: 20 July 2015 07:31
To: CALNDR-[hidden email]
Subject: Re: Dee-Cecil Calendar and Simon Cassidy's Epacts
 
Hi Walter and Calendar people,
I don't think there's any chance of making the Church adopt any alternative way of computing the vernal equinox.  Keep in mind that the very purpose of the gregorian reform was to make the vernal equinox fall on a fixed date.
The only way to improve the Easter computus would require fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle.
 
On Mon, Jul 20, 2015 at 5:56 AM, Walter J Ziobro <[hidden email]> wrote:
Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.


-Walter Ziobro





--
Amos Shapir
 
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Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Karl Palmen

Dear Walter and Calendar People

 

I don’t think there is such a record, else there’d be a Wikipedia article about it.

 

I recall Simon suggesting two Easter epact rules for it

(1) Epacts follow 19-year cycle as for Gregorian Calendar, but corrections occur one every 231 years when the 33-year cycle starts on a given day of week, the correction is equivalent to a Gregorian solar equation correction (epacts decremented by 1). The complete cycle would be 131,670 years.

(2) The Moonkey rule, where a Saltus lunae occurs once every 19 years not counting years whose number is divisible by 12. This cycle results in a 6840-year year/month cycle. The complete cycle would be 75,240 years.

 

Karl

 

16(07(27

 

Friday Queen of Clubs 2017, ISO deck

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Walter J Ziobro
Sent: 24 March 2017 02:26
To: [hidden email]
Subject: Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

 

Dear Karl:

Your post reminded me of a thought that have had, for which I cannot think of any answer:

Is there any record of when Dee and Cecil  proposed their calendars with the 33 year leap day rule, whether they themselves proposed how Easter should be determined by their calendars?   It seems from what I have seen that Simon Cassidy was actually the first person to devise a lunar equation rule for any 33 year calendar.

-Walter Ziobro

 

 

 

-----Original Message-----
From: Karl Palmen <[hidden email]>
To: CALNDR-L <[hidden email]>
Sent: Wed, Mar 22, 2017 9:04 am
Subject: Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

Dear Amos, Walter and Calendar People

 

I looked back at some old notes and wonder what Amos meant by

fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle

 

It could mean fixing Easter date to something like the 2nd Sunday in April.

It could mean making Easter repeat on a 400-year cycle.

In neither case would Easter be lunar.

 

Perhaps it just means fixing the equinox date to Gregorian 21 March.

Actually I think the underlying issue is what day do we count the epacts relative to.  The number of days that the paschal full moon occurs after the ecclesiastical equinox day is determined in a simple manner from the epact. I think Walter wants to preserve that, but vary the ecclesiastical equinox date so that it jitters less. Then a method such as Simon Cassidy’s Moonkey epacts could be applied.

 

If we both fix the ecclesiastical epact date and preserve the simple relationship between the number of days that the paschal full moon occurs after the ecclesiastical equinox day and the epact, then the choice of good epact rules available is seriously constrained. This arises from the jitter of the Gregorian calendar of 2.1975 days, we don’t want all the jitter to be transferred to the Paschal full moon. One way of reducing the transfer of jitter is to have every correction of the 19-year cycle at a year ending in 00, which include the dropped leap years. Better still, decrement the epact by 1 at every dropped leap year (solar equation) and increment by 1 once every 300 or 400 years (lunar equation). This is what the Gregorian computus does.

 

The Gregorian computus corrects the 19-year cycle by simply decrementing or incrementing the epacts by 1. One could also correct by changing the Golden Number of the Saltus Lunae.  This offers finer control of 1/570 month instead of 1/30 month and allows the Easter days to follow a shorter cycle such as the 18,000-year cycle.

 

Karl

 

16(07(25

 

From: East Carolina University Calendar discussion List [[hidden email]] On Behalf Of Amos Shapir
Sent: 20 July 2015 07:31
To: CALNDR-[hidden email]
Subject: Re: Dee-Cecil Calendar and Simon Cassidy's Epacts

 

Hi Walter and Calendar people,

I don't think there's any chance of making the Church adopt any alternative way of computing the vernal equinox.  Keep in mind that the very purpose of the gregorian reform was to make the vernal equinox fall on a fixed date.

The only way to improve the Easter computus would require fixing the lunar cycle algorithm, within the 400-year Gregorian solar cycle.

 

On Mon, Jul 20, 2015 at 5:56 AM, Walter J Ziobro <[hidden email]> wrote:

Dear  Mr Otero:

Your reference to the Sacraffia article in which the Pope offered to standardize the date of Easter, got me thinking about how this could be done.  If the Lunisolar method of determining Easter is to be retained, but improved, two standing proposals could be used to facilitate this.

The first could be to determine the Ecclesiastical Vernal Equinox according to the Dee-Cecil Calendar, or some calendar with a variant of the 33 year leap day rule.   This would cause the Ecclesiastical Vernal Equinox to fall on a narrower range of dates, and,more often on the date of the astronomical northward equinox.  An exposition of the Dee-Cecil Calendar can be found here:    

http://www.hermetic.ch/cal_stud/dee-cecil-calendar.htm

An alternative to adopting the Dee-Cecil Calendar might be simply to have the Ecclesiastical Vernal Equinox determined solely by a 33 year rule, independently of any specific calendar.

The second could be to change the rules whereby the lunar epacts are shifted.  Simon Cassidy has proposed alternative rules whereby the epacts are adjusted gradually every twelfth year, instead of all at once on certain century years, thereby minimizing lunar jitter, and maximizing correspondence with the astronomical lunar phases.  An abstract outlining his proposals can be found here:

      http://www.hermetic.ch/cal_stud/cassidy/metonic_epacts.htm

Again, if it is decided that the Ecclesiastical Vernal Equinox is to be determined independently of any specific calendar, and a 33 year rule is chosen, the system of epacts could be applied to the Ecclesiastical Vernal Equinox (EVE) itself.  That is to say, an alternative table of epacts  showing the age of the moon on the EVE could be generated, with the next 14th day of a lunation determined to be the Paschal Full Moon for that year.


-Walter Ziobro




--

Amos Shapir