Talk:Callippic cycle
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Less accurate
[edit]Not an improvement on the observed (variable days/month) lunar calendar. 27759 days / 76 years = 365.2500 days/year. Whereas the Meton cycle: 29.530589 days x 235 lunations / 19 years = 365.24676 days/year. The average tropical year is 365.24219 days.
FYI, Dr Irv B more recently proposes: 4366 lunations / 353 years = 365.24236 days/year. If fixed: 128931 days/353 = 365.24363 days/year.
Although, the Meton cycle assumes OBSERVED lunations and pre-calculated leap years (13 months). Whereas the Callippic cycle pre-calculates days (per lunation) and leap years. To fixed days, the Meton cycle is either 6939 days / 19 = 365.211 days/year or 6940 days/19 = 365.263 days/year.
Alexgenaud (talk) 00:41, 24 January 2022 (UTC)
IF
[edit]There are too many "if"s in this article which suggests and actually indicates it is all hypothetical conjecture and original research. In fact the article says if we add this and if we subtract that. And changing wording to say if he did this or if he did that, is still conjecture. I would be removed if I said Egyptian 25-year lunar calendar could come from 75-year old Abraham, or that perhaps Abraham criticized its 75 years with what he knew of 76 years at his city Ur. How is it any different to conjecture what Meton did, or to say how the Callipic cycle works and then demand at the close of the article that no works survive. IF no works survive, then whose original research work is this article. The year 432bc and 330bc in itself does not prove the origin of 19-year as older than 76-year. In fact, four years of 1461 days (without Julian calendar) precedes this period by 1000 years. In Babylon (1626bc) the passing of 744 years proved to Amizaduga that the 186 leap days of Sothis were only 180 seasonal leaps of the sun. Thus whether the Metonic and Callipic is Sothic or seasonal does matter. The attempt of 76 years with 19 leap days added to 365-day calendar is most definitely Sothic, not seasonal. And it is easily divided by 19, not the opposite of taking 19 years as 6940 days and quadruple it making it as 27,760 claim it fits 76 years by subtracting 1 day. To the contrary, when dividing the original 76-year we find that it requires a day omitted on the 4th cycle of 19. Thus IF Meton did not subtract this day, but retained every 19-yer cycle as 27,760 days, then it was he revising the already-existing 76-year cycle to say that the advance of that one day is closer to Sothic drift. Most of these Wikipedia articles ignore the drift of Sothis from July 17 to 18 to July 20 in 2000 years from 2000bc to our Era and that it has stayed at July 20 only because it is at 6 hour right ascension (90 degree longitude). I have listed only two IFs in criticism, and are far less than the ifs in this article. Lunar conjunctions listed (example 304 years = 4x 76 year, or 16x 19 year)
1443bc G.Mar 24 =Apr 6 @ 00:11
1139bc G.Mar 25 =Apr 4 @ 15:22
835bc G.Mar 26 =Apr 3 @ 15:11
531bc G.Mar 28 =Apr 3 @ 08:23
227bc G.Mar 28 =Apr 1 @ 17:14
78ad G.Mar 30 =Apr 1 @ 01:12
Sothic Julian the cycle whether 76-year or 19-year retreats 5 days backward from Sirius. While seasonally it advances 6 days forward.