Talk:Maya calendar/Archives/2006/December

How did they get October 13th, 4722 CE as the end date?

How did they get October 13th, 4722 CE as the end date? --Mdsats 05:57, 3 December 2006 (UTC)
Take a look at the 13-baktun Cycle:
13.0.0.0.0 - August 11, 3114 BCE
1.0.0.0.0 - November 13, 2719 BCE
2.0.0.0.0 - February 16, 2324 BCE
3.0.0.0.0 - May 21, 1930 BCE
4.0.0.0.0 - August 23, 1536 BCE
5.0.0.0.0 - November 26, 1142 BCE
6.0.0.0.0 - February 28, 747 BCE
7.0.0.0.0 - June 3, 353 BCE
8.0.0.0.0 - September 5, 41 CE
9.0.0.0.0 - December 9, 435 CE
10.0.0.0.0 - March 13, 830 CE
11.0.0.0.0 - June 15, 1224 CE
12.0.0.0.0 - September 18, 1618 CE
13.0.0.0.0 - December 21, 2012 CE
1.0.0.0.0 - March 5th, 2407 CE
2.0.0.0.0 - June 28th, 2801 CE
3.0.0.0.0 - October 1st, 3195 CE
4.0.0.0.0 - January 3rd, 3590 CE
5.0.0.0.0 - April 7th, 3984 CE
6.0.0.0.0 - July 11th, 4378 CE
7.0.0.0.0 - October 13th, 4722 CE
8.0.0.0.0 - January 16th, 5167 CE
9.0.0.0.0 - April 20th, 5561 CE
10.0.0.0.0 - July 24th, 5955 CE
11.0.0.0.0 - October 26, 6349 CE
12.0.0.0.0 - January 29, 6744 CE
13.0.0.0.0 - May 3, 7138 CE
1.0.0.0.0 - August 5th, 7532 CE

In no way is October 13th, 4722 CE the end date, its the 7th baktun of the next Age. This is assuming you go by the 13-baktun Cycle (where 13=0). As the article itself states the last creation date was August 11, 3114 BCE (13.0.0.0.0), and the next is definitely December 21st, 2012.

The only way you can arrive at October 13th, 4722 CE as the end date is if you go by the 19-baktun Cycle, where in 14.0.0.0.0 = March 5th, 2407 CE and 19.19.17.19.19 = October 12th, 4722 CE, but if you do that it would be incorrect since the baktun only ranges from 1-13, as stated in the article itself. There is nothing above 13, after that a new Age begins.

--Mdsats 05:58, 3 December 2006 (UTC)

Who said they have an end date in this creation? There is no evidence whatsoever that there is a limit to 13 baktuns. Just because the previous creation ended on a 13th baktun doesn't mean in any way that this creation will end on a 13th baktun. For that matter there is no evidence whatsoever that the Maya had any firm date at all for the end of this creation. The baktun count absolutely does not roll over back to zero after the 13th baktun in this creation, but must continue through the 14th-19th baktuns in this creation or the calendar round on the 1 piktun date from Palenque could not be correct. 1.0.0.0.0.0 (note the five zeros) must be in 4772 CE, otherwise the entire calendar system doesn't work. --grr 16:29, 14 December 2006 (UTC)

Venus Information

(grr 23:38, 24 March 2006 (UTC)) I don't think the Venus references belong here as it doesn't directly talk about the Calendar. I think there there needs to be a completely separate page on Maya Astronomy. I haven't done it, but it should be considered.

I agree since the Dresden Codex is not the calendar. I also want to know if anyone can tell me if the Venus Almanac in the Dresden Codex is predictive of observational.

204.227.223.74 18:42, 14 June 2006 (UTC)Tlaloc

It's predictive, but must have taken hundreds of years of very careful observations and recordings to form. The correction numbers on the page are an incredible achievement. --grr 16:58, 14 December 2006 (UTC)

Problem for Astronomy Software?

The article states: The use of software that is based on the proleptic Gregorian calendar can be problematic for.... Astronomical research. For example, to study ancient observations on stelae or in the codices, one may convert a Long Count to days, months, and years. This date would then be entered into an astronomy program. The astronomy program will use the standard Julian/Gregorian calendar so this will cause a major error.

I've read and reread this section, but it's not at all clear to me why this should be so. Perhaps it could be clarified for the less sharp among us. Lusanaherandraton 08:05, 11 August 2006 (UTC)

Read about the Julian and Gregorian calendars. Consider that the proleptic Gregorian calendar isn't used in astronomy (or much of anything else except Maya calendar software). A brief explanation of this was in the article but was removed in favor of refering people to articles about these calendars. 204.227.223.63 20:03, 14 August 2006 (UTC)Tlaloc

Important information about calendars:

In 46 BC Julius Caesar decreed that the calendar would consist of twelve months of approximately 30 days each and that there would be an extra day in February every four years. This is the Julian calendar. The length of the year in the Julian calendar was 365.25 days - close to the length of the solar year of 365.2422 days. By 1582 there was a significant distance between Christmas and the winter solstice and Easter and the spring equinox. Pope Gregory XIII, with help from astronomer Luigi Lillo, reformed the calendar. Ten days were removed from October so that the fourth was followed by the 15th and the system of leap years was changed so that centuries are only leap years if they are evenly divisible by 400 so for example 2000 was a leap year but 1900 wasn't. This is the Gregorian calendar. Dates before 46 BC are converted to Julian calendar dates. This is called the proleptic Julian calendar.

Another important factor in calculating calendar dates is the fact that there are two ways of naming years before one. In historical dating the year 1 BC (or BCE). is followed by 1 A.D. In astronomical dating there is a year 0 so -1 is followed by 0 which is followed by 1. Since numerical systems have a value of zero this makes sense for anyone trying to do calendric calculations.

The Julian/Gregorian calendar is the standard way of doing these calculations and is the way that people doing Maya calendar calculations convert Long Count 0,0,0,0,0 to Monday, September 6 -3113 (3114 BC).

Many of the books about the Maya and most of the software available for Maya calendar conversions uses a revisionist system of calendrics called the proleptic Gregorian calendar. In this system all dates before October 15th, 1582 are converted to the Gregorian calendar, including Gregorian leap centuries, as if it had been in use all along. This is how one converts Long Count 0,0,0,0,0 to August 11th, 3114 BC.

204.227.223.63 23:35, 14 August 2006 (UTC)Tlaloc

Since different cultures adopted the Gregorian calendar at different times, using the proleptic Gregorian calendar provides a consistent scheme in talking about western dates. It's not just 1582 (the date that Catholic states switched) that's the problem. If you are looking at a date written in the 1600's, and it happens to be an English document, it's still in the Julian date system since the English (and their colonies, including the United States) didn't make the switch until 1752. No matter when you want to apply the switch, there is a date when you must drop days from the calendar. The proleptic Gregorian calendar has the advantage that there is never a time when 10 or so days just vanish from the calendar that you have to take into account. The Julian/Gregorian thing is especially problematic since Spain (a Catholic state) made the switch in 1582, right at the time that many colonial documents about the Maya were being written...so if trying to figure out calendrics, you need to be very aware of what date system they were the using when they wrote the document. A good Maya calendar program avoids the issue of the switch by showing both proleptic Gregorian and Julian dates side by side. --grr 16:51, 14 December 2006 (UTC)

Another way to provide a consistent scheme for talking about wastern dates would be to use the Julian calendar for modern dates. The Orthodox church never accepted Gregorian calendar reform and still uses the Julian calendar today.

Extra Cycle Information

I gleaned this off another calendar website awhile ago. (wish i had the link) but what of the extra cycles than what is on the page here?

Cycle	Composed of	Total Days	Years (approx.)
kin	1
uinal	20 kin	20
tun	18 uinal	360	0.986
katun	20 tun	7200	19.7
baktun	20 katun	144,000	394.3
piktun	20 baktun	2,880,000	7,885
calabtun	20 piktun	57,600,000	157,704
kinchiltun	20 calabtun	1,152,000,000	3,154,071
alautun	20 kinchiltun	23,040,000,000	63,081,429

--—The preceding unsigned comment was added by Goodrob (talk • contribs) 24 October 2006.

The higher-order cycles and their pseudo names are briefly mentioned in the article, but I suppose they could be expanded upon a little more. However, since the article is already quite lengthy, I think it may be time to (re-)split some of the subtopics (eg Maya Long Count calendar into their own separate articles, and use the present one to summarise the main points and organise the related material (see also earlier discussion on this, somewhere above).--cjllw | TALK 23:36, 23 October 2006 (UTC)

The site is http://www.fourmilab.ch/documents/calendar/ . I don't know about the cycles. Reywas92^Talk 21:34, 5 December 2006 (UTC)