Talk:Revised Julian calendar

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[edit] Discussion

there are other orthodox churches, such as the ASSYRIAN, the SYRIAC,& THE ARMENIAN CHURCHES who are also using the Julian calendars (both original and revised)--69.194.255.150 22:06, 7 Jan 2005 (UTC). The ASSYRIAN, the SYRIAC,& THE ARMENIAN CHURCHES are not Eastern Orthodox but Non-Chalcedonian (They are considered Heretic Churches by Eastern Orthodox, Catholic and Protestant Churches) see http://en.wikipedia.org/wiki/Chalcedonian

_ _ ... despite Eastern Orthodox calendar redirecting here. I'm creating a Dab to remedy that, and those who know more will want to fix it.
_ _ I came here pursuing the idea that Christmas
... is ... observed in much of the world on 25 December, or on 7 January in most Eastern Orthodox Churches
suggests that EO would say
I believe Christmas is Jan 7
contrary to my impression that they would say
Christmas is Dec 25, but most of the world uses a bad calendar and therefore celebrates it a couple of weeks early
_ _ Even if this article were on the Julian calendar it would have been indecently inaccessible. The statement
the two calendars will first differ in 2800
is buried inside an incredibly legalism- and math-ridden article, and that is the one that i needed to tell me that this article is totally worthless for what i came here for, which is rewording the Xmas article.
--Jerzy•t 18:32, 18 January 2006 (UTC)

[edit] Moveable feasts and the date of Easter

I'm unclear about this point:

Liturgical objections to the New Calendar stem from the fact that it adjusts only those liturgical celebrations that occur on fixed calendar dates, leaving all of the commemorations on the moveable cycle on the original Julian Calendar.

Computus#Julian_calendar gives more detail:

The method for computing the date of the ecclesiastic Full Moon that was standard for the Latin (Catholic) church before the Gregorian calendar reform, and is still used today by Eastern Christians, made use of an uncorrected repetition of the 19-year Metonic cycle in combination with the Julian calendar. ... In this case, the epact was counted on 22 March, the earliest acceptable date for Easter.
  • Putting these two statements together, is the following correct?
  • that the epact in both JC and RJC is 22 March JC, i.e. 4 April RJC
  • And that the moveable feasts are, on average, 13 days later in the year relative to fixed feasts
  • Assuming this is correct, one obvious question is: why was the epact of Easter not moved from 22 March JC to 22 March RJC as part of the change?
  • Was it because the proposal to switch Easter to an astronomical calculation was the only one considered, and once that was rejected no backup plan was thought of?
  • Or was the idea consciously rejected for some pragmatic or theological reasons?

jnestorius(talk) 22:08, 15 October 2007 (UTC)

The Revised Julian calendar does not now and never had an epact, even in its rejected astronomical form, to place on 22 March or any other date. An astronomical Easter using instants for the vernal equinox and for the full moon does not need an epact to determine Easter. Only if the vernal equinox and the full moon are whole days is an epact necessary. It is the Julian calendar, which does use whole days for all of these parameters, that has an epact on 22 March, which is never converted into a Revised Julian calendar date or even into a Gregorian calendar date. Eastern Christians use the Julian calendar, not the Revised Julian calendar, to calculate Easter. The Julian Easter was never incorporated into the Revised Julian calendar. Thus some Eastern Orthodox churches use both the Revised Julian calendar (for fixed feasts) and the Julian calendar (for movable feasts). No country uses either calendar—all countries in Eastern Europe use the Gregorian calendar as their official and legal calendar.
Because only a few churches use the Revised Julian calendar whereas almost all Eastern Orthodox churches use the Julian Easter, it is more appropriate to regard the latter as the reference. When both the Revised Julian fixed dates and Julian movable dates are converted into the Gregorian calendar, the fixed dates are a few days earlier than the range of movable dates. Thus the fixed feasts will be 13 days earlier than the movable dates only until 2099. Beginning in 2100 they will be 14 days earlier, in 2200 15 days earlier, etc. — Joe Kress 08:11, 16 October 2007 (UTC)
Thanks, Joe. I think this is a question of my misunderstanding the terminology rather than the calculations. My previous interpretation was something like:
  • "The Roman Catholic Church uses the Gregorian Calendar"
  • "The Greek Orthodox Church uses the Revised Julian Calendar"
  • "The Russian Orthodox Church uses the Julian Calendar"
So you're saying "Revised Julian Calendar" refers to both parts of the 1923 proposal: the Easter date calculation (never adopted) and the general date calculation (adopted by some churches).
"Calendar" as I was interpeting it above seems to encompass a mixture of liturgical year and calendar. Whatever this may be called, it consists of:
  1. a method of calculating the date
  2. an assignment of fixed feasts to particular dates
  3. a method of calculating the date of Easter
  4. an assignment of moveable feasts to particular offsets from Easter
Then we have:
Church date calc fixed feasts Easter epact Easter formula moveable feasts
Roman Catholic Church Gregorian Roman Catholic calendar of saints March 22 New Style Gregorian computus RC moveable feasts
Finnish Orthodox Church Gregorian Eastern Orthodox liturgical calendar March 22 New Style Gregorian computus Paschal Cycle
(1923 synod proposal) Revised Julian Eastern Orthodox liturgical calendar N/A Astronomical Paschal Cycle
Greek Orthodox Church Revised Julian Eastern Orthodox liturgical calendar March 22 Old Style Dionysian computus Paschal Cycle
Russian Orthodox Church Julian Eastern Orthodox liturgical calendar March 22 Old Style Dionysian computus Paschal Cycle
If and when this table is accurate, I think it would be a useful addition to this article, or liturgical year, or some other related article; the current text is a bit tricky to get one's head around, at least if my experience is typical. jnestorius(talk) 12:01, 16 October 2007 (UTC)
Your interpretation corresponds with my interpretation. However, the terminology and rhetoric used by the various Orthodox churches is quite ambiguous. Indeed, some Orthodox bishops have complained that the words used by the various Orthodox churches when they adopted the Revised Julian calendar could mean that they actually adopted the Gregorian calendar for their fixed feasts. The problem is that both calendars produce the same dates for fixed feasts until 2800. The use of the term new calendar (added by another editor) is a prime example. Does that mean the Revised Julian calendar created in 1923 or does it mean the Gregorian calendar adopted by Greece in the same year, 1923? Furthermore, various authoritative sources state that the country of Greece adopted the Gregorian calendar anywhere between 1916 and 1924. Without access to a copy of the actual decree, I have ignored early adoption years, and think that 1924 is the year that the Greek Orthodox Church adopted the Revised Julian calendar. I should mention that I generally ignore any discussion of liturgy and how feasts are celebrated—my interest lies in the technical aspects of the various calendars. — Joe Kress 19:06, 16 October 2007 (UTC)

[edit] Revised Julian error-graph/users

Does anyone know if there is a graph representing the difference between the true seasons and the revised julian calendar like this[1] for the Gregorian calendar? Also any numbers on how many people use this calendar? Crd721 (talk) 10:14, 9 February 2008 (UTC)

A graph of the vernal equinox (rather than the winter solstice) relative to the Revised Julian calendar is here (#3 on this page). However, the Revised Julian calendar uses the mean tropical year as its benchmark, not the vernal equinox nor any other solstice or equinox. The mean tropical year is the average of all solsticial and equinoctial years so it is the average of all curves on this page (#6 on this page). The average year of the Revised Julian calendar is in light gray. The mean tropical year in terms of mean solar days appears to be getting shorter because the length of the mean solar day is getting longer due to tidal friction. Thus the number of those days in the relatively constant mean tropical year decreases over time. When Milankovitch devised his rule the mean solar day was thought to be constant.
Although more autocephalous and autonomous Orthodox churches use the Revised Julian calendar than use the old Julian calendar, their total population is dwarfed by the population of the Russian Orthodox Church alone (255,000,000 worldwide), let alone the few others who still use the old Julian calendar. From the limited population figures I've found, my guess is that about 50,000,000 use the Revised Julian calendar. — Joe Kress (talk) 10:01, 10 February 2008 (UTC)

[edit] Vernal equinox year?

However, the vernal equinox year is slightly longer [than the tropical year, by context ], so for a few thousand years the Revised Julian calendar does a slightly worse job the Gregorian calendar at keeping the vernal equinox on or close to March 21.

What is this supposed to mean? The tropical year is measured from vernal equinow to vernal equinox. Septentrionalis PMAnderson 18:40, 2 May 2008 (UTC)

The word slightly is the keyword. Note:

  • Vernal equinox year: 365.242375 days
  • RJC average year: 365.242222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222 days
  • GC average year: 365.2425 days
  • Average of 2 averages years: 365.2423611111111111111111111111111111111111111111111111111111111111111111111111111111111111 days

So the word "slightly" makes sense. Georgia guy (talk) 19:18, 2 May 2008 (UTC)

So what is the meaning of vernal equinox year, which can differ from the tropical year of 365.242199 days? Septentrionalis PMAnderson 19:29, 2 May 2008 (UTC)
The vernal equinox year (365.242374 days) is the time between vernal equinoxes. In contrast, the mean tropical year (365.242190 days) is the average of all tropical years, including the vernal equinox year (365.242374 days), the summer solstice year (365.241626 days), the autumnal equinox year (365.242018 days), the winter solstice year (365.242740 days), and all those in between these four. The vernal equinox year is a little closer to the mean Gregorian year (365.242500 days) than it is to the mean Revised Julian calendar year (365.242222 days), hence the Gregorian calendar is slightly better than is the Revised Julian calendar at keeping the vernal equinox near March 21. — Joe Kress (talk) 08:09, 3 May 2008 (UTC)
Ah, thank you. I see that is only a temporary statement, true for the next few millennia, since the vernal equinox year varies with the perihelion. Since the RJ calendar has a cycle of 6,300 years, this seems less than material. Septentrionalis PMAnderson 13:51, 3 May 2008 (UTC)