Talk:Iranian calendars

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Yamara 14:23, 14 February 2008 (UTC)


Let's add some URL for 'Persian date today' or simply converter. --Ilya 12:02, 16 Dec 2003 (UTC)

Ilya, I have an online Online calendar converter of unknown accuracy -- OJW

midnight at what longitude? --juuitchan

I'm guessing midnight in Persia (Iran), which according to Iran has time zone UTC +3.30. -- DavidCary 19:30, 12 May 2004 (UTC)

"confusion between the astronomers average tropical year (365.2422 days, approximated with mistaken near 128-year cycles) and the mean interval between vernal equinoxes (365.2424 days, approximated here with a near 33-year cycle)."

OK, I'm confused. What is the difference ? Should we add a link to the Year article which should (hopefully) explain the difference ? -- DavidCary 19:30, 12 May 2004 (UTC)

Hi David,

It is confusing. I didn't write it, but I think I understand somewhat. The "Mean Tropical year" is 365.24219 days. It defines the average period for the average seasonal event to repeat. However the earth's orbit is an ellipse, so its motion is speeding up and slowing down over the year. In addition that year defined by the ellipse period (Anomalistic years) 365.2596 days is different, so when you go exactly 1 mean tropical year forward, the earth will be moving at a slightly different orientation in the ellipse and a different speed. Thus a given seasonal event will happen at a slightly different time. This difference is cumulative so the exact lengths of the various seasons will oscillate over time. Thus, if you measure a year defined between March Equinoxes will not be the same length as defined between September Equinoxes!

The quote "the mean interval between vernal equinoxes (365.2424 days, approximated here with a near 33-year cycle)." implies that the CURRENT period between VE is close to 365.2424 days rather than the mean 365.2422 days. So the Iranian calendar actually keeps the VE closer to a given date than would using the mean year which would work better over the long term.


I'm scare to rewrite anything here, too busy to do a good job without adding more confusion. I had a watch on this page because I added the pretty graphic showing the 33-year rule running over 500 years against the mean tropical year. My purpose was to contrast the 33 year rule with the Gregorian 400 year rules which diverge much more greatly with the tropical mean dates.

--Tomruen 21:52, 12 May 2004 (UTC)

OK, now that I've thought about what you've written (and read Year and Tropical year), I think I understand.

When I first read that

 the vernal equinox year is 365.24237404 days
 the autumn equinox year is 365.24201767 days

I got the impression that it was saying that those 2 days, currently half a year apart, would drift closer and closer together until they occured on the same day, which is clearly impossible.

Now I think I understand:

Earth's axis precesses, pointing at different stars in a small circle that takes around 20 000 years (?). This makes the mean Tropical year slightly different than the sidereal year. If Earth traveled in a circle around the sun, then the vernal equinox year would be the same as the autumn equinox year, and all 4 equinox/solstice points would be exactly the same amount of time apart.

Earth travels in an ellipse. This makes the sun appear to move through the stars in its great circle faster at some times, slower at others. The sun appears to move the fastest when Earth is at perihelion (currently around 2 January, making the winter season the shortest season). The sun appears to move the slowest when Earth is at apohelion (currently around _ July, making the summer season the longest season). If Earth's axis did not precess, then the the vernal equinox year would be the same as the autumn equinox year, each season would last exactly the same amount of time from one year to the next, but the seasons would be 4 different lengths.

The combination of the ellipse and the precession causes the longest season to gradually change: from winter to spring to summer to fall to winter again (over the course of 20 000 years (?) ).

At the present millenium, we've just switched from fall being the longest month to winter being the longest month. (We've just switched from spring being the shortest month to summer being the shortest month). This means that during this and the previous millenium, spring is expanding, summer is shrinking, fall is shrinking, winter is expanding. So the winter (southern) solstice is coming earlier each year, and northern (summer) solstice is coming later every year.

This makes the southern solstice year a bit shorter than the nothern solstice year.

(Except my conclusion is exactly the *opposite* of what Tropical year says. I've got a sign bit flipped somewhere.)

EditHint: Perhaps we could combine your comment, my comment, polish it bit, and stuck into the Tropical Year article.

-- DavidCary 13:04, 13 May 2004 (UTC)

The seasons need to be reversed: in the thirteenth century summer overtook spring for the longest season. Winter is currently shortest, therefore. So now autumn is expanding relatively rapidly, summer is expanding at a slower rate, spring is shrinking rapidly, and winter is shrinking at a slower rate. This is because perihelon, and thus the shortest seasons, is on January 4 and shifting forward in the calendar.

-- 04:16, 21 Mar 2005

the "Khayyam cycle"[edit]

Tropical year mentions the "Khayyam cycle"; should we mention that in this article as well ? Perhaps by simply extending the last sentence "(365.2424 days, approximated here with a near 33-year cycle)" to "(365.2424 days, approximated here with a 33-year cycle called the Khayyam cycle)" ?

-- DavidCary 13:04, 13 May 2004 (UTC)


Do we have any information on weekday names for this calendar, and the start of the week? I've found the following names, but I'm no expert. "Yekshanbeh, Doshanbeh, Seshhanbeh, Chaharshanbeh, Panjshanbeh, Jomeh, Shanbeh"

-- OJW 01:04, 30 June 2004 (UTC)

Hello OJW. I wrote most of this article. The reason I did not include the weekdays, is because technically the week is neither a natural cycle of any sort, nor technically a part of this calendar systems. This is also the case for the Gregorian and many other calendars. --K1 04:21, 30 Jun 2004 (UTC)

Hello K1. At the risk of this becoming a "calendar-programming help", it's pretty difficult to produce or understand a calendar of any sort without weekdays. (try finding a gregorian calendar in the shops without any mention of weeks...) - why do we not consider it part of the calendar system? -- OJW (4 Jul 2004, not logged-in)

I did not design this calendar system, so it is not me who doesn't consider the week as part of this system, the designers of this calendar system did not include a concept called "week" in their design. As I mentioned to you before, the Gregorian calendar also does not have a concept called "week" inherent in its design. I suggest that you take a look at the official Calendar FAQ which has been maintained by Claus Tøndering for the past several years. There is a whole section about the "week" in that FAQ, infact immediately following the section about the Persian Calendar. --K1 19:30, 5 Jul 2004 (UTC)

Some more detail on the Calendar FAQ section on weeks: it starts with the phrase "The Christian, the Hebrew, the Islamic, and the Persian calendars all have a 7-day week".

Yes, but it is not generally a good idea to read just the first sentence of an entire section and draw conclusions. If you read the first paragraph, try to also read the last paragraph. Anyway, the concept of "week" is more of religious or administrative nature, rather than an inherent part of this calendar system. The day, the month and the solar year all are natural phenomena, the week is not. --K1 20:19, 5 Jul 2004 (UTC)

Whether weeks should or should not technically be part of the calendar, the answer to the original question posed is this: there are seven days in week in Iranian calendars published today. The week starts with "Shanbeh," (the "h" is not pronounced) which coincides with "Saturday," and ends in "Jomeh." Jomeh is considered more holly than other days of the week and is the weekly holiday. The days are as follows:

Shanbeh, Yek Shanbeh, Doe Shanbeh, Seh Shanbeh, Chahar Shanbeh, Panj Shanbeh, Jomeh

In Farsi: yek means one, doe means two, seh means three, chahar means four, and panj means five. (talk) 23:19, 22 December 2010 (UTC) 15:19, 22 DEC 2010

If you suggest this article needs to be merged with "Solar Islamic Calendar" perhaps you should first explain what exactly "Solar Islamic Calendar" is. I have spent a good part of my life working on calendars and have never heard of such a calendar. On the other hand, the Persian Calendar is a very well-known one among people who know a few things about calendars. Best Regards, Sergio C.

The merge message here is a double merge message, and I had not originally put it there. These two are clearly not about different calendar systems. If you think one of the articles should be deleted, you should raise that on the Wikipedia:Votes for Deletion. roozbeh 11:42, Jul 25, 2004 (UTC)
Thank you for the link. I created a Vote for Deletion. Please vote as you like. Best Regards, Sergio.
Merging simply means "Combining the best features of both articles". This article here is much more informative than the other, but frankly most the information it offers it deeply buried inside it, historical references mixed with info about the function of the calendar itself. Will try to make some changes for purposes of readability and hopefully you'll approve. Aris Katsaris 22:56, 29 Jul 2004 (UTC)

Missing important details[edit]

I think one important detail is missing in the description of the Persian calendar system and that is the "great grand cylces". The modern Iranian calendar has a much higher accuracy than stated in the current version of this page. To read the missing detail (and the code), you may take a look at John Walker's page: [1] As one of the few calendars designed in the era of accurate positional astronomy, the Persian calendar uses a very complex leap year structure which makes it the most accurate solar calendar in use today. Years are grouped into cycles which begin with four normal years after which every fourth subsequent year in the cycle is a leap year. Cycles are grouped into grand cycles of either 128 years (composed of cycles of 29, 33, 33, and 33 years) or 132 years, containing cycles of of 29, 33, 33, and 37 years. A great grand cycle is composed of 21 consecutive 128 year grand cycles and a final 132 grand cycle, for a total of 2820 years. The pattern of normal and leap years which began in 1925 will not repeat until the year 4745! Each 2820 year great grand cycle contains 2137 normal years of 365 days and 683 leap years of 366 days, with the average year length over the great grand cycle of 365.24219852. So close is this to the actual solar tropical year of 365.24219878 days that the Persian calendar accumulates an error of one day only every 3.8 million years. --Salarian 13:11, 23 Mar 2005 (UTC)


The second paragraph, as edited by User:Amir85 [2] is not neutral. It should be edited to be more neutral. (Compare to my version.) 07:57, 4 October 2005 (UTC)

The second paragraph is about the accuracy of the calendar. It assumes a criterion of accuracy that is not universally accepted (days out compare to mean tropical year rather than Vernal Equinox year) and furthermore is not appropriate for a calendar based on the vernal equinox.

Also because the Iranian calendar is observation-based it is perfectly accurate, but unlike the Gregorian calendar it is not perfectly predictable.

I think the 1 day in 141,000 year error arises from a comparison between an arithmetic version of the calendar which uses a 2820-year cycle and mean tropical year. This 2820-year cycle calendar actually differs from the observation-based calendar more often than a simpler 33-year cycle arithmetic calendar.

Also because of changes in Earth's rotation and other things, no aritmetic calendar can be expected to last longer than a few thousand years so a figure of one day out every 141,000 years would be practically meaningless.

I'd want even more revision does to this second paragraph.

Karl Palmen 08:20 UT 4 October 2005

I don't think this is a NPOV issue. More like factual accuracy or self-contradiction. The article heading clearly states the calendar isn't rule based, so the calendar is totally accurate by definition (that is, at least as accurate as the calculations/observations that determine it).
I would however, contest the claim that the calendar is 'almost unknown in the West'. I think there are a number of people aware that, e.g., the Kurds celebrate new year on/near March 21, and the Kurdish calendar is based on this one. Claiming it is almost unknown in the west is like claiming that the theory of special relativity is almost unknown in the 'West'. squell 19:07, 8 October 2005 (UTC)
I've been bold and edited it. squell 02:11, 23 October 2005 (UTC)

Merge with Jalali calendar[edit]

Jalaali calendar redirects here, Jalali calendar is a separate article. — squell 02:37, 23 October 2005 (UTC)

Jalali is a system on which the Iranian calendar is based on. The significance being the point of origin. There can be (and have been) other calendars based on Jalali but with different origins. I disagree with the merge, perhaphs some materials from here should be move over to the other article. Kaveh 3:14, 10 December 2005 (UTC)

The motivation was that both articles described the same calendar, and that the way you spelled it decided which article you got. This discussion has been superseded by the copy-vio tag on the other article, though. squell 14:45, 10 December 2005 (UTC)

New year time[edit]

I suggest the template {{solstice-equinox}} or a similar template which shows the equinox time to be used on the main page to show the new year's time. Mahanchian 10:40, 18 March 2006 (UTC)

Might be a problem since these times are probably in UTC and afaik, the Iranian calendar uses Teheran local (apparent?) time. Don't have a clue what's used elsewhere squell 11:06, 18 March 2006 (UTC)
It doesn't matter because beginning of the Iranian new year is at spring equinox that is a single moment all around the world regardless of time zone, therefore UTC can be used as reference and each timezone can be worked out based on that. Alternativly a new template can be created based on Tehran's time zone (GMT +3.5)Mahanchian 14:56, 19 March 2006 (UTC)
It does matter. From what I've read, the determination of new years day is based on the Tehran midnight that falls closest to the spring equinox. This means that the exact timezone and equation of time have to be taken into account for, to deal with borderline cases. In any case, the solstice-equinox template does not suffice, and a specialized template for this sort of information would not likely be useful to any other article. By the way; there's already an online source for new year moments: K.M. Borkowsi [3]. — squell 15:49, 19 March 2006 (UTC)
Caveat: I'm not too sure whether mean time or local apparent time is used. Borkowski seems to use mean time. — squell 10:55, 20 March 2006 (UTC)

citation needed: "Sino-Uighur"[edit]

" The law goes further and officially deprecates the Sino-Uighur year cycles which were unofficially but commonly used."
Googling "Sino-Uighur" and "calendar" or "year cycle" yields only self-referential Wikipedia results. We need a more reliable source on this one.--CiteCop 17:35, 28 July 2006 (UTC)

Two primary sources would be:
  • E. S. Kennedy, "The Chinese-Uighur Calendar as Described in the Islamic Sources", Isis 55 (1964) 435-443.
  • Benno van Dalen, E. S. Kennedy, Mustafa K. Saiyid, "The Chinese-Uighur Calendar in Tûsî's Zîj-i Îlkhânî", Zeitschrift für Geschichte der Arabisch-Islamischen Wissenschaften 11 (1997) 111-152.
Nasir al-Din Tusi founded an observatory at Maragha in 1257.
Joe Kress 00:39, 29 July 2006 (UTC)
Thank you, Joe. It didn't occur to me to look under "Chinese-Uighur calendar". There were much better results for that search. I've edited the article accordingly.--CiteCop 19:36, 29 July 2006 (UTC)

Iranian vs Jalali calendar[edit]

I reverted the move of this article from Iranian calendar to Jalali calendar made by Salarmehr because it was made without discussion. It ignores the objections made above (#Merge with Jalali calendar) and violates the principles of Wikipedia:Naming conventions, which requires that the article should be named in a manner that "the majority of English speakers would most easily recognize". Jalali calendar is almost totally unknown to English speakers. — Joe Kress 05:22, 12 August 2007 (UTC)

Except Hijri Shamsi, this calender is still known by the public as Jalali Calender in Iran. You can call it Modern Jalali Calender but I don't think we must change the original name just because the names should be named in a manner that the majority of English speakers would most easily recognize. There is no such policy in Wikipedia and we are not making new names of that English native speakers could recognize them easier. Wikipedia is an encyclopedia and we are not here in Wikipedia. I know the order of the days is difference with the original Jalali Calender when they decided it to be the only official calender of Persia (Iran) in 1925, but later in 1979 in the constitution of the Islamic Republic of Iran (Article No. 17), the Islamic calendar is also considered as the official calender of the Islamic Republic of Iran. As a result, currently this calender is not the only official calender of Iran. I think we should revert it to Jalali Calender, and call the old one The ancient Jalali Calender and the new one The Modern Jalali Calender. Does any one else has any other ideas? --Najand (talk) 23:14, 18 March 2008 (UTC)

Computer formula[edit]

I believe this formula correctly determines whether a numbered year in the Iranian calendar is a leap year:

((year) mod 33) mod 4 = 3

 Randall Bart   Talk  00:32, 28 February 2008 (UTC)

The following discussion is an archived discussion of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the proposal was support for move.--Fuhghettaboutit (talk) 23:45, 27 April 2009 (UTC)

Requested move[edit]

I propose move to "Iranian calendar":

  • A little google search gives 5 hits for Solar Hejri (calendar) and 29 hits for Solar Hijri (calendar) but there are 679 hits for Iranian calendar. According to WP:NAME, the most common name should be used.
  • Also a good portion of the current page talk about Ancient Iranian calendar, Zoroastrian calendar, and Parthian and later modified Iranian calendar. None of these are strictly speaking Hejri.

I think the page should be moved to "Iranian calendar".--Xashaiar (talk) 17:20, 19 April 2009 (UTC)

The page was moved on 17 April 2009 by نگونبانگونی from Iranian calendar, where it had been since its creation in 2004, to Solar Hejri calendar without discussion. Furthermore, the extensive discussion that already existed at Talk:Iranian calendar was not moved on 17 April. Also see the discussion of an attempted move in 2007 at Talk:Iranian calendar#Iranian vs Jalali calendar. As already noted, most English sources use the name "Iranian calendar" while most English readers would not know what a "Solar Hejri calendar" was. So according to Wikipedia:Naming conventions#Use the most easily recognized name the name should be "Iranian calendar". — Joe Kress (talk) 20:55, 21 April 2009 (UTC)
Something is wrong. Even the move tag is wrong: it asks to move "Solar Hejri Calendar" to itself! Should I edit it manually?--Xashaiar (talk) 21:18, 21 April 2009 (UTC)
I misunderstood your comment. I misused Template:Move—now corrected. — Joe Kress (talk) 18:03, 22 April 2009 (UTC)
I already tried moving it back before I requested an admin to do so via the above box and entry in Wikipedia:Requested move#22 April 2009. The move tag normally enters the current name of the article which you are indeed expected to edit to your desired new name. However, the move will fail because the edit history of "Iranian calendar" has more than one edit line, the original mover's (نگونبانگونی), an anon, and your attempt and revert. Also note that the correct original name of the article was "Iranian calendar", not the capitalized form "Iranian Calendar", which itself has four edit lines in its history. نگونبانگونی also originally moved "Iranian calendar" to "Solar Hejri" before finally moving it to its present location, "Solar Hejri calendar". — Joe Kress (talk) 01:35, 22 April 2009 (UTC)
Support. In addition to using English (which is the real issue), this must be one of very few articles with a term transliterated from Farsi using an e. Septentrionalis PMAnderson 03:06, 22 April 2009 (UTC)
Comment shouldn't it be Persian Calendar? (talk) 11:19, 22 April 2009 (UTC)
No. See the second reason in my first comment: Also a good portion.... --Xashaiar (talk) 13:24, 22 April 2009 (UTC)
Oppose use Persian Calendar instead, per Talk:Iranian calendar. (talk) 04:35, 23 April 2009 (UTC)
The above discussion is preserved as an archive of the proposal. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Iranian vs Islamic[edit]

Dear auther, I'am really confused that if this page is the Iranian calendar or Islamic one!! I unfortunatly can see many Islamic information on diffrent parts that have no relationship to Iran! most important one is "Public holidays and anniversaries" part. I think we can put many information on this part which is related to Iran,and its better not to fulfil the page with islamic information. be smiley, KMM —Preceding unsigned comment added by Nanopharmacy (talkcontribs) 01:20, 27 June 2009

You are right. There are some sources (like that of Encyclopaedia Iranica's article, etc..) given in the text which can help to improve the article and give enough weight to Iranian calendar. If you are willing to help and extract some info from those articles please let me know.--Xashaiar (talk) 23:53, 27 June 2009 (UTC)

Removal of material[edit]

I was offended by a user who said persian sources are useless on wikipedia. It was a bit racist. I had made mistakes in my sentencing, which I rectified now, but the sources were solid. If you knew it needed correction you should have made the corrections not deleting the material.-- (talk) 02:06, 3 February 2010 (UTC)

No offense was intended. My statement "this is English Wikipedia so Persian refs are useless" was an inadequate attempt within the limited space provided for an edit summary to cite Wikipedia verifiability rules, which only allow non-English sources on English Wikipedia if they provide information that is not available in English sources (see Wikipedia:Verifiability, Non-English sources. This allows English readers to verify the information in the article. I have identified several English sources describing Birashk's intercalation scheme, including his own book, available in English under the title A Comparative Calendar of Iranian, Muslim Lunar, and Christian Eras for 3000 Years. I am composing a replacement for your version, which I will leave in the article until mine is ready. The major change is mentioning that Birashk's scheme tracks the wrong year and thus his stated accuracy is wrong. He tracks the mean tropical year which is the average year of all equinoxes and solstices, but only the vernal equinox matters in the Jalali calendar. The vernal equinox year is approximately 0.0002 days longer, which means that Birashk's scheme develops an error of one day in only 5000 years, not one day in 3.8 million years. More important is whether his scheme ever places Nowruz on the wrong day, which may occur much sooner than 5000 years. I remember reading somewhere that Birashk stated that his intercalation scheme should be followed even if it places the vernal equinox on the wrong date! — Joe Kress (talk) 15:44, 3 February 2010 (UTC)

Year 2549[edit]

Hello, can someone shed a little light on the ancient Persian New Year calendar. I mean isn't it 2549 since the time of Cyrus and Noruz, when kings from different nations used bring him gifts? —Preceding unsigned comment added by Ditc (talkcontribs) 00:33, 9 February 2010 (UTC)

The article states at Iranian calendar#Modern era from 1925 that in 1976, the Shah decreed that Solar Hejri year 1355 became the imperial year 2535. Thus the first imperial year was the year that Cyrus the Great acceded to the throne in 559 BC (not his birth year many years earlier). This would mean that during Gregorian year 2010 the imperial year 2569 would have begun if the Solar Hejri year had not been reinstated in 1978. Your year 2549 would imply a first imperial year 20 years after Cyrus began his reign, after he had conquered many nations, inducing their kings to bring him gifts. This would be even more arbitrary then the beginning of his reign, which is a well known year. His birth year is assigned to be two different years, either 600–599 BC or 576–575 BC.
Regarding Nowruz, in Achaemenid times the official year began at Nowruz at the vernal equinox, but popular usage placed Nowruz at the summer solstice. In Sasanid Persia gifts were presented to the king at Nowruz. These two dates for Nowruz persisted into the Islamic period. See "Nawruz" in the Encyclopaedia of Islam. — Joe Kress (talk) 07:37, 9 February 2010 (UTC)

help with one article[edit]

See Sepandarmazgan#Date_of_celebration. I have no idea if the correspondance to the Gregorian calendar is correct. --Enric Naval (talk) 15:34, 10 February 2010 (UTC)

Some points[edit]

other name of Iranian calendar in English Language is Persian calendar. the local name of this calendar is (Persian: گاهشماری هجری خورشیدی‌Gahshomari-ye Hejri-ye Khorshidi means Solar Hejri calendar). this calendar is Official Calendar in Iran and Afganistan. There is no Mehregan in Public holidays in Iran. I use the iranian offical calendar and this program Wrote Public holidays in Iran to Gregorian Calendar. Thanks. Negonbangoni (talk) 11:10, 28 March 2010 (UTC)

Article lede[edit]

The lede of this article is quite confusing because it cannot decide whether it is about Iranian calendars in general or the Solar Hejri calendar. WP article ledes should be used to say what the article is about. I'll try to clean it up. Ashmoo (talk) 17:44, 31 March 2010 (UTC)

Changing title to "Iranian calendarS"[edit]

Per concerns raised by User:Negonbangoni and Ashmoo in the preceding sections, I propose changing the title of the article to Iranian calendars (with an -S). This will avoid any confusion between:

  • the modern or current version of the Iranian calendar, which is called Hijri Shamsi or Hijri Khorshidi (cf. Encyclopaedia Iranica), and which is the official calendar of the governments of Iran and Afghanistan
  • the Jalali calendar organized in the 11th century
  • the Pre-Islamic calendars in Iran (Zoroastrian calendar, Achaemenid calendar, and others)

In that case the title will be in agreement with the introductory sentence "...refer to any in a succession of a set of calendars invented or used for over two millennia in Iran and related societies". The readers will automatically get the message that Iranian calendars refer to a series of calendars invented in Pre-Islamic and Islamic periods in Iran, and is not a single calendrical system and that the current official calendars in Iran and Afghanistan is just part of the series of Iranian calendars.

We can then divide the article in three sections: (1) Pre-Islamic or Ancient calendars (Zoroastrian, Achaemenid, etc.), (2) Medieval Era or Islamic Period (Jalali calendar), and (3) Modern calendar or Solar Hijri (Hijri Khorshidi) (in Iran, and in Afghanistan). I base my proposition (changing the title) on the scholarly sources such as:

Iranica has employed the calendars in plural sense "Calendars". And I think it is the accurate approach. Let's see what other editors have got to say on this. Please kindly comment clearly if you support changing the title, or if you do not. Ariana (talk) 11:21, 11 May 2010 (UTC)

  • Support per above. Xashaiar (talk) 11:42, 11 May 2010 (UTC)
  • Support. Although I would prefer 'The calendars of Iran'. Ashmoo (talk) 18:55, 11 May 2010 (UTC)

Changing link[edit]

change link to farsi article to this fa:گاه‌شماری ایران Saeedbf (talk) 12:14, 2 October 2010 (UTC)

Jalali section[edit]

Under the section titled "Medieval era : Jalali calendar" the article states:

"In 1079, the team also computed the length of a solar year as 365.24219858156 days.[4] (The actual value was 365.2422464 days).[5]"

What is this actual value? Is it the length of the mean tropical year in 1079? From reading the corresponding reference and the page history, it would seems so. If so, I doubt that is what the 1079 team was calculating. Wouldn't they have been calculating the time between spring equinoxes? According to the Wikipedia entry on "Tropical year", the mean tropical year and the times between equinoxes/solstices can differ quite dramatically (at least in the third or fourth decimal). If so, this is an unfair comparison for determining the accuracy of the value calculated by the 1079 team.

Also, the article says right before the previous statement:

"However, the original Jalali calendar based on observations (or predictions) of solar transit would not have needed either leap years or seasonal adjustments."

That sentence is misleading. Of course the Jalali calendar needs leap years and seasonal adjustments based on mathematics. Otherwise they wouldn't have been able to create a written calendar for future dates. They would have had to wait for the observations. Isn't that the definition of a calendar? The committee that created the Jalali calendar was composed of serious mathematicians as well as astronomers (a minor edit that should also be made). Beck8888 (talk) 00:11, 4 October 2010 (UTC)

The article needs substantial revision, which I am working on in my spare time. 365.24219858156 days is the average solar year of the 2820-year cycle advocated by the late Ahmad Birashk, see page 13 of A concise review of the Iranian calendar. The 1079 team left no records—Omar Khayyam did not even mention the Jalali calendar in his own book of calendars. A few later medieval Muslim astronomers left their opinions. Jamshīd al-Kāshī (died 1429) mentioned the 33-year cycle averaging 365.242424 days. Ulugh Beg (died 1449) alternated 29- and 33-year cycles averaging 365.241935 days. Qotb al-Din Kazeruni (died 1311) alternated 33- and 37-year cycles averaging 365.242857 days.
Because the solar year between vernal equinoxes (the vernal equinox year) is not constant [5] no arithmetical rule which specifies leap years at regular intervals will last for more than a few thousand years before unacceptable errors accumulate. Only modern astronomical calculations can predict most future vernal equinoxes and hence the character (common or leap) of most future years (at least 4000 years). But a crucial component, ΔT, can only be predicted within a minute or so hundreds of years in advance, so whether the vernal equinox is before or after noon is not yet known for some future years (2091 (1469–70), 2124 (1502–03), 2157 (1535–36), 2223 (1601–02), 2256 (1634–35)), and will not be known until those future years become present years. — Joe Kress (talk) 05:03, 4 October 2010 (UTC)
Thanks Joe. Sounds like you have it under control. I look forward to reading your revision. Thanks also for that great reference to Heydari-Malayeri. His article clears up most if not all the confusion. According to him, the 1079 team's year calculation in days was accurate to three decimal places. If they were off by less than 0.0001 then that's less than 9 seconds. Not bad for 1079 when the Western calendar was off by 11 minutes and still more accurate than the Gregorian calendar we use today. Heydari-Malayeri has also written about other interesting historical subjects. Thanks again. Beck8888 (talk) 06:55, 7 October 2010 (UTC)

Persian Wikipedia and its weird mix of Gregorian and Iranian calendar dates[edit]

Is it just me or are the calendar dates there mixed up like heck? Well, I tried a test with people born or deceased in 1951 and I *actually* got them both! Phil Collins: (born) fa:فیل_کالینز in Gregorian date. Now someone else, Shams Langeroodi: (died) fa:محمد_شمس_لنگرودی His death happened in VERY SAME year as Collins' birth, but date given in Solar Hejri date this time! So, is there any system or logic behind it? Maybe it depends whether they're local Iranians or foreign people? Or how is this determined? Actually, these weird mix-ups never do any good. -andy (talk) 13:47, 25 January 2011 (UTC)

Seasonal error[edit]

Why is the Seasonal Error section separated from the chart it discusses? Erusse estelinya (talk) 19:23, 2 March 2011 (UTC)

Afghan calendar month names[edit]

I've just left at note at Wikipedia talk:WikiProject Time which I will copy here too:

Start of copied note

While stub-sorting I've found Worai, created almost exactly a year ago, total content: "Worai is the first month of the Afghan Calendar. It starts with the beginning of the spring season." and a navbox template to the other 11 months, {{AfghanMonths}}. The template's link "Afghan Calendar" redirects to Iranian calendars, and the names used for this set of 12 month stubs appear to be different transliterations of the names in the "Afghan Pashto" column of the table at Iranian_calendars#Month_names ("Wray" for "Worai", etc). These month listings in the table don't link to the set of 12 stubs. But, on looking, the top left item in the table doesn't link to the article Farvardin (created 2007 and still pretty minimal, though longer than Worai and co.)

If the set of Afghan month stubs are to be useful, they should presumably be linked from that table... and perhaps given redirects under the spellings used there... I leave it to a calendar enthusiast to pick up the ball at this stage, I've done as much as I'm interested in doing, by sorting that stub and telling you about it. Perhaps all the month names should just redirect to Iranian calendars, from both (all?) transliterations? Good luck. PamD 22:25, 12 July 2012 (UTC)

End of copied note PamD 22:31, 12 July 2012 (UTC)

The Chinese twelve animal calendar introduced to Iran by the Mongols[edit]

Mentioned in

The Turks acquired their calendar system from China.

Page 84,+...+The+Mongols+in+turn+adopted+this+Turkish+(+animal)+version+of+the+Chinese+calendar+from+the+Uighurs,+who+played+an+...&dq=Professor+Bazin+has+demonstrated+with+a+wealth+of+detail+how+the+eastern+Turks+adapted+the+Chinese+civil+calendar,+...+The+Mongols+in+turn+adopted+this+Turkish+(+animal)+version+of+the+Chinese+calendar+from+the+Uighurs,+who+played+an+...&hl=en&sa=X&ei=X78wVMXhFsqayATT9YGYAw&ved=0CBwQ6AEwAA

Page 263,+the+ancient+Turks+adopted+a+form+of+the+Chinese+luni-solar+calendar,+either+directly+from+China+or+via+the+Sogdians.+Later,+this+passed+from+the+Uyghur+Turks+to+the+Mongols,+who+in+turn+introduced+it+in+their+empire+in+Persia,+where+it+was+quite+widely+used,+alongside+the+...+The+Mongols+translated+the+Turkish+animal+names+into+their+own+language,+in+many+cases+(nos+.&dq=Before+entering+the+ddr+al-Isldm,+the+ancient+Turks+adopted+a+form+of+the+Chinese+luni-solar+calendar,+either+directly+from+China+or+via+the+Sogdians.+Later,+this+passed+from+the+Uyghur+Turks+to+the+Mongols,+who+in+turn+introduced+it+in+their+empire+in+Persia,+where+it+was+quite+widely+used,+alongside+the+...+The+Mongols+translated+the+Turkish+animal+names+into+their+own+language,+in+many+cases+(nos+.&hl=en&sa=X&ei=U78wVP__Bc6nyATNiIHgAw&ved=0CCAQ6AEwAA,+the+ancient+Turks+adopted+a+form+of+the+Chinese+luni-solar+calendar,+either+directly+from+China+or+via+the+Sogdians.+...+The+Mongols+translated+the+Turkish+animal+names+into+their+own+language,+in+many+cases+(nos.+3-5,+8-10)+using+words+that+are,+in+fact,+borrowed+from+Turkish+(where+,+in+turn,+some+of+the+names+derive+from+Iranian+or+Chinese);+in+Persian+texts+the+Turkish+and+the+Mongolian+names+are+used+interchangeably+(with+inevitable+variations+in+...+Year+10+takighu+takiya+cock+Year+1+1+it+nokay+dog+Year+12+tonuz+ghakay+pig+The+animal+cycle+continued+to+be+used+in+Persia+until+the+beginning+of+the+twentieth+century,+generally+in+conjunction+with+the+months+of+the+Djalalf+calendar.+x.&dq=Before+entering+the+ddr+al-Isldm,+the+ancient+Turks+adopted+a+form+of+the+Chinese+luni-solar+calendar,+either+directly+from+China+or+via+the+Sogdians.+...+The+Mongols+translated+the+Turkish+animal+names+into+their+own+language,+in+many+cases+(nos.+3-5,+8-10)+using+words+that+are,+in+fact,+borrowed+from+Turkish+(where+,+in+turn,+some+of+the+names+derive+from+Iranian+or+Chinese);+in+Persian+texts+the+Turkish+and+the+Mongolian+names+are+used+interchangeably+(with+inevitable+variations+in+...+Year+10+takighu+takiya+cock+Year+1+1+it+nokay+dog+Year+12+tonuz+ghakay+pig+The+animal+cycle+continued+to+be+used+in+Persia+until+the+beginning+of+the+twentieth+century,+generally+in+conjunction+with+the+months+of+the+Djalalf+calendar.+x.&hl=en&sa=X&ei=IsYwVOStI46myASg8IKIAw&ved=0CB4Q6AEwAA

Page 113,+but+within+the+Chinese+astronomical+tradition,+and+in+Chinese.+...+Sections+3,+5,+10,+and+1+1+below+give+tables+listing+the+names+of+such+things+as+the+duodecimal+animal+cycle,+the+sexagesimal+cycle+of+days+...+Most+of+these+Chinese+and+Turkish+names+are+standard+and+well+known.+...+Sections+12+through+17+define+and+describe+the+concepts+used+in+the+construction+of+the+calendar,+such+as+the+luni-solar+year,+lunar+...&dq=calendar+as+described+in+the+IlkhanT+Zlj+were+operating+in+Central+Asia,+but+within+the+Chinese+astronomical+tradition,+and+in+Chinese.+...+Sections+3,+5,+10,+and+1+1+below+give+tables+listing+the+names+of+such+things+as+the+duodecimal+animal+cycle,+the+sexagesimal+cycle+of+days+...+Most+of+these+Chinese+and+Turkish+names+are+standard+and+well+known.+...+Sections+12+through+17+define+and+describe+the+concepts+used+in+the+construction+of+the+calendar,+such+as+the+luni-solar+year,+lunar+...&hl=en&sa=X&ei=CMMwVMfsA8WfyAS3gYJ4&ved=0CB4Q6AEwAA

Page 50,+given+in+T.l.+...+5+as+in+the+modern+Chinese+calendar.+jylb+taqiqu+is+the+name+of+the+tenth+animal,+the+cock,+in+the+Turkish+list+of+twelve+...&dq=The+12+shih+are+put+into+one+to+one+relation+with+the+12+earthly+branches+and+with+the+cycle+of+12+animals,+given+in+T.l.+...+5+as+in+the+modern+Chinese+calendar.+jylb+taqiqu+is+the+name+of+the+tenth+animal,+the+cock,+in+the+Turkish+list+of+twelve+...&hl=en&sa=X&ei=xsIwVMmsHIacyQSpkYA4&ved=0CCAQ6AEwAA

Page lxi;+it+forms+the+basis+of+their+calendar+and+is+in+all+...+Modern+calendar+pictures,+whether+of+Mongolian+or+Turkish+origin,+show+a+tendency+to+replace+the+Chinese+dragon+by+...&dq=Among+all+the+nations+of+central+Asia+we+find+the+%22cycle+of+12+animals%22;+it+forms+the+basis+of+their+calendar+and+is+in+all+...+Modern+calendar+pictures,+whether+of+Mongolian+or+Turkish+origin,+show+a+tendency+to+replace+the+Chinese+dragon+by+...&hl=en&sa=X&ei=ncIwVNeqBMWeyASpuYGYCA&ved=0CCAQ6AEwAA

Rajmaan (talk) 00:43, 4 May 2014 (UTC)