Equivalence of calendar dates, pre-1582

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Equivalence of calendar dates, pre-1582

Christoph Päper-2
If we agree to use the following definitions for the course of this thread,


- RC  = Roman (Solar) Calendar:
        4-year leap rule, 12 months, 365+ days
        year starts 1 January
        leap date is 29 February
        no formal year count

- JC  = Classic Julian Calendar:
        RC 31:28+:31:30:31:30:31:31:30:31:30:31
        nominal Christian epoch
        year 1 AD (= +0001) succeeds 1 BC (= -0001), no year zero

- JCp = Proleptic Julian Calendar:
        like JC, but year 0001 succeeds 0000 and -0001,
        valid at least -9999 through +9999

- GC  = Classic Georgian Calendar:
        JC changed to 4:100:400 leap rule
        valid at least +1583 through +9999

- CC  = Catholic Calendar:
        JC before mid-October 1582, GC thereafter

- GCp = Proleptic Georgian Calendar:
        like GC with year count of CC, i.e. no year zero
        no dates skipped in 1582 or ever

- IC  = International Calendar:
        like GCp, but year 0001 succeeds 0000 and -0001,
        valid at least -9999 through +9999

Let the date notation for all of them be ±CCYY-MM-DD. Which calendars do agree on dates for which periods of time?
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Re: Equivalence of calendar dates, pre-1582

Phil De Rosa
Hi Christoph.   I think you mean Gregorian Calendar and not Georgian.

Phil De Rosa

-----Original Message-----
From: Christoph Päper
Sent: Saturday, March 11, 2017 4:31 AM
To: [hidden email]
Subject: Equivalence of calendar dates, pre-1582

If we agree to use the following definitions for the course of this thread,


- RC  = Roman (Solar) Calendar:
        4-year leap rule, 12 months, 365+ days
        year starts 1 January
        leap date is 29 February
        no formal year count

- JC  = Classic Julian Calendar:
        RC 31:28+:31:30:31:30:31:31:30:31:30:31
        nominal Christian epoch
        year 1 AD (= +0001) succeeds 1 BC (= -0001), no year zero

- JCp = Proleptic Julian Calendar:
        like JC, but year 0001 succeeds 0000 and -0001,
        valid at least -9999 through +9999

- GC  = Classic Georgian Calendar:
        JC changed to 4:100:400 leap rule
        valid at least +1583 through +9999

- CC  = Catholic Calendar:
        JC before mid-October 1582, GC thereafter

- GCp = Proleptic Georgian Calendar:
        like GC with year count of CC, i.e. no year zero
        no dates skipped in 1582 or ever

- IC  = International Calendar:
        like GCp, but year 0001 succeeds 0000 and -0001,
        valid at least -9999 through +9999

Let the date notation for all of them be ±CCYY-MM-DD. Which calendars do
agree on dates for which periods of time?
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Re: Equivalence of calendar dates, pre-1582

Karl Palmen
In reply to this post by Christoph Päper-2
Dear Christoph and Calendar People

Christoph, please explain the purpose and scope of the thread any why we need all seven of these definitions for it?

I don't like the use of the minus sign for 'BC'. It is arithmetically misleading.
Why not convert BC dates to astronomical numbering before using YYYY-MM-DD?
Why make all dates YYYY-MM-DD?

Karl

16(07(16

-----Original Message-----
From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Christoph Päper
Sent: 11 March 2017 12:31
To: [hidden email]
Subject: Equivalence of calendar dates, pre-1582

If we agree to use the following definitions for the course of this thread,


- RC  = Roman (Solar) Calendar:
        4-year leap rule, 12 months, 365+ days
        year starts 1 January
        leap date is 29 February
        no formal year count

- JC  = Classic Julian Calendar:
        RC 31:28+:31:30:31:30:31:31:30:31:30:31
        nominal Christian epoch
        year 1 AD (= +0001) succeeds 1 BC (= -0001), no year zero

- JCp = Proleptic Julian Calendar:
        like JC, but year 0001 succeeds 0000 and -0001,
        valid at least -9999 through +9999

- GC  = Classic Gregorian Calendar:
        JC changed to 4:100:400 leap rule
        valid at least +1583 through +9999

- CC  = Catholic Calendar:
        JC before mid-October 1582, GC thereafter

- GCp = Proleptic Gregorian Calendar:
        like GC with year count of CC, i.e. no year zero
        no dates skipped in 1582 or ever

- IC  = International Calendar:
        like GCp, but year 0001 succeeds 0000 and -0001,
        valid at least -9999 through +9999

Let the date notation for all of them be ±CCYY-MM-DD. Which calendars do agree on dates for which periods of time?
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Pre-& Post 1582 dates Re: Equivalence of calendar dates, pre-1582

Brij Bhushan metric VIJ
Karl, all sits,
>Why make all dates YYYY-MM-DD?
I may not be as qualified to 'impress' that ISO:8601 dating for dates be recognized/corrected in the format YYYY-MM(ww)-DD followed by Time of the Hour-minutes-seconds (Decimalised or otherwise); along with 'Day of the week' .
It is easy to use AD/BCE dates leaving the option open to "standardize" introducing Year 0000. Count of days for all other events may get modified from 1582, October 04/15th at the instant (while implementing Papal Bull) since varied for calendars in use by Nations.
Regards,
Brij Bhushan metric VIJ
Author, Brij-Gregorian Modified Calendar
Wednesday, 2017 March 15H14:86 (decimal)

Sent from my iPhone

> On Mar 13, 2017, at 9:12 AM, Karl Palmen <[hidden email]> wrote:
>
> Why make all dates YYYY-MM-DD?