Solar Hijri calendar

The Solar Hijri calendar[a] (Persian: گاه‌شماری هجری خورشیدی, romanizedGâhšomâri-ye Hejri-ye Xoršidi; Pashto: لمريز لېږدیز کلیز, romanized: lamrez legdez kalhandara) is a solar calendar and one of the various ancient Iranian calendars. It begins on the March equinox as determined by astronomical calculation for the Iran Standard Time meridian (52.5°E, UTC+03:30) and has years of 365 or 366 days. It is the modern principal calendar of both Iran and Afghanistan, and is sometimes also called the Shamsi Hijri calendar, and abbreviated as SH, HS or, by analogy with AH, AHSh.

The Solar Hijri calendar is one of the oldest calendars in the world, as well as the most accurate solar calendar in use today. Since the calendar uses astronomical calculation for determining the vernal equinox, it has no intrinsic error.[2][3][4][5] It has the same epoch (start date) as the Lunar Hijri calendar used by the majority of Muslims (known in the West as the Islamic calendar): the Hijrah, the journey of the Islamic prophet Muhammad and his followers from Mecca to Medina in the year 622.[6][7] Unlike the latter, its years are solar years rather than lunar years.

Each of the twelve months corresponds with a zodiac sign; their names are the same as ancient Zoroastrian names from the Zoroastrian calendar – in Afghanistan on the other hand, the names of the zodiacal signs are used instead. The first six months have 31 days, the next five have 30 days, and the last month has 29 days in usual years but 30 days in leap years. The ancient Iranian New Year's Day, which is called Nowruz, always falls on the March equinox. While Nowruz is celebrated by communities in a wide range of countries from the Balkans to Mongolia, the Solar Hijri calendar itself remains only in official use in Iran and Afghanistan.

A Solar Hijri calendar of year 1383 SH showing the second month of Ordibehesht (thus April–May of 2004; see conversion table below). The months’ name comes from the Avestan word for Asha.

Structure

Epochal date

The calendar's epoch (first year) corresponds to 622 CE in the Gregorian calendar. It dates from the Hijrah, but as it is a solar calendar, its year numbering does not coincide with the Lunar Hijri calendar.

Days per month

The first six months (Farvardin–Shahrivar) have 31 days, the next five (Mehr–Bahman) have 30 days, and the last month (Esfand) has 29 days in common years or 30 days in leap years. This is a simplification of the Jalali calendar, in which the commencement of the month is tied to the sun's passage from one zodiacal sign to the next. The sun is travelling fastest through the signs in early January (Dey) and slowest in early July (Tir). The current time between the March and September equinoxes is about 186 days and 10 hours, the opposite duration about 178 days, 20 hours, due to the eccentricity of Earth's orbit. (These times will change slowly due to precession of the Earth's rotation, becoming inverted after around 12 500 years.)

Leap years

The Solar Hijri calendar produces a five-year leap year interval after about every seven four-year leap year intervals. It usually follows a 33-year subcycle with occasional interruptions by a single 29-year subcycle. The reason for this behaviour is (as explained above) that it tracks the observed vernal equinox.

Some predictive algorithms had been suggested, but were inaccurate due to confusion between the average tropical year (365.2422 days) and the mean interval between spring equinoxes (365.2424 days). These algorithms are not generally used (see Accuracy).

New Year's Day

The Solar Hijri calendar year begins at the start of spring in the Northern Hemisphere: on the midnight in the interval between the two consecutive solar noons that includes the instant of the March equinox. Hence, the first mid-day is on the last day of one calendar year, and the second mid-day is on the first day (Nowruz) of the next year.

Months

OrderDaysPersian (Iran)Dari (Afghanistan)Kurdish (Iran)PashtoEquivalent in Gregorian
Native ScriptRomanizedNative ScriptRomanizedSorani ScriptKurmanji ScriptNative ScriptRomanized
131فروردینFarvardinحملHamal (Aries)خاکەلێوەXakelêweوریWray (Aries)March – April
231اردیبهشتOrdibeheshtثورSawr (Taurus)گوڵانGullan (Banemer)غويیǦwayáy (Taurus)April – May
331خردادKhordadجوزاJawzā (Gemini)جۆزەردانCozerdanغبرګولیǦbargoláy (Gemini)May – June
431تیرTirسرطانSaraṭān (Cancer)پووشپەڕPûşperچنګاښČungā́x̌ (Cancer)June – July
531مرداد / امردادMordad / AmordadاسدAsad (Leo)گەلاوێژGelawêjزمریZmaráy (Leo)July – August
631شهریورShahrivarسنبلهSonbola (Virgo)خەرمانانXermananوږیWáǵay (Virgo)August – September
730مهرMehrمیزانMizān (Libra)ڕەزبەرRezberتلهTә́la (Libra)September – October
830آبانAbanعقربʿAqrab (Scorpio)گەڵاڕێزانXezellwer (Gelarêzan)لړمLaṛám (Scorpio)October – November
930آذرAzarقوسQaws (Sagittarius)سەرماوەزSermawezليندۍLindә́i (Sagittarius)November – December
1030دیDeyجدیJadi (Capricorn)بەفرانبارBefranbarمرغومیMarǧúmay (Capricorn)December – January
1130بهمنBahmanدلوDalvæ (Aquarius)ڕێبەندانRêbendanسلواغهSalwāǧá (Aquarius)January – February
1229/30اسفند / اسپندEsfand / EspandحوتHūt (Pisces)ڕەشەمەReşemeكبKab (Pisces)February – March

The first day of the calendar year, Nowruz ("New Day"), is the greatest festival of the year in Iran, Afghanistan, and some surrounding historically Persian-influenced regions. The celebration is filled with many festivities and runs a course of 13 days, the last day of which is called siz-dah bedar ("13 to outdoor").

The Dari (Afghan Persian) month names are the signs of Zodiac. They were used in Iran in the early 20th century when the solar calendar was being used.

Days of the week

In the Iranian calendar, every week begins on Saturday and ends on Friday. The names of the days of the week are as follows: shambe (natively spelled "shanbeh", شنبه), yekshambe, doshambe, seshambe, chæharshambe, panjshambe and jom'e (yek, do, se, chæhar, and panj are the Persian words for the numbers one through five). The name for Friday, jom'e, is Arabic (جمعه). Jom'e is sometimes referred to by the native Persian name, adineh [ɒːdiːne] (آدینه). In some Islamic countries, Friday is the weekly holiday.

Calculating the day of the week is easy, using an anchor date. One good such date is Sunday, 1 Farvardin 1372, which equals 21 March 1993. Assuming the 33-year cycle approximation, move back by one weekday to jump ahead by one 33-year cycle. Similarly, to jump back by one 33-year cycle, move ahead by one weekday.

As in the Gregorian calendar, dates move forward exactly one day of the week with each passing year, except if there is an intervening leap day when they move two days. The anchor date 1 Farvardin 1372 is chosen so that its 4th, 8th, ..., 32nd anniversaries come immediately after leap days, yet the anchor date itself does not immediately follow a leap day.

Current usage

Iran

A Persian-language contract published in Tehran on April 14, 1910, which used Lunar Hijri calendar

On 21 February 1911, the second Iranian parliament adopted as the official calendar of Iran the Jalali sidereal calendar with months bearing the names of the twelve constellations of the zodiac and the years named for the animals of the duodecennial cycle; it remained in use until 1925.[1] The present Iranian calendar was legally adopted on 31 March 1925, under the early Pahlavi dynasty. The law said that the first day of the year should be the first day of spring in "the true solar year", "as it has been" ever so. It also fixed the number of days in each month, which previously varied by year with the sidereal zodiac. It revived the ancient Persian names, which are still used. It specified the origin of the calendar to be the Hijra of Muhammad from Mecca to Medina in 622 CE.[8] It also deprecated the 12-year cycles of the Chinese-Uighur calendar, which were not officially sanctioned but were commonly used.

Earlier starting year (1975–1979)

In 1975,[1] Shah Mohammad Reza Pahlavi changed the origin of the calendar to the beginning of Cyrus the Great's reign as its first year, rather than the Hejra of Muhammad. Overnight, the year changed from 1354 to 2534. The change lasted until the Iranian revolution in 1979, at which time the calendar reverted to Solar Hijri.[9]

Afghanistan

Afghanistan legally adopted the official Jalali calendar in 1922[1] but with different month names. Afghanistan uses Arabic names of the zodiacal signs; for example, the 1978 Saur Revolution took place in the second month of the Solar Hijri calendar (Persian Ordibehesht; Saur is named after Taurus). The Solar Hijri calendar is the official calendar of the government of Afghanistan,[10] and all national holidays and administrative issues are fixed according to the Solar Hijri calendar. Under the Taliban's first rule, the lunar Hijri calendar was imposed instead, thus changing the year overnight from 1375 to 1417.[11]

Tajikistan

Tajikistan does not use the Solar Hijri calendar and never did so, despite being part of the Persian-speaking world. Although the country does celebrate Nowruz, the official New Year's Day is the 1st of January in the Gregorian calendar,[12] which is also the case in other non-Persian speaking Iranian or Turkic communities ranging from Eastern Europe to Western China. Tajikistan's capital, Dushanbe, is taken from the Solar Hijri calendar and translates to "Monday" in Persian.[13]

Comparison with Gregorian calendar

The Solar Hijri year begins about 21 March of each Gregorian year and ends about 20 March of the next year. To convert the Solar Hijri year into the equivalent Gregorian year add 621 or 622 years to the Solar Hijri year depending on whether the Solar Hijri year has or has not begun.

Correspondence of Solar Hijri and Gregorian calendars (Solar Hijri leap years are marked *)[14]
33-year
cycle[15]
Solar Hijri yearGregorian yearSolar Hijri yearGregorian year
11354*21 March 1975 – 20 March 19761387*20 March 2008 – 20 March 2009
2135521 March 1976 – 20 March 1977138821 March 2009 – 20 March 2010
3135621 March 1977 – 20 March 1978138921 March 2010 – 20 March 2011
4135721 March 1978 – 20 March 1979139021 March 2011 – 19 March 2012
51358*21 March 1979 – 20 March 19801391*20 March 2012 – 20 March 2013
6135921 March 1980 – 20 March 1981139221 March 2013 – 20 March 2014
7136021 March 1981 – 20 March 1982139321 March 2014 – 20 March 2015
8136121 March 1982 – 20 March 1983139421 March 2015 – 19 March 2016
91362*21 March 1983 – 20 March 19841395*20 March 2016 – 20 March 2017
10136321 March 1984 – 20 March 1985139621 March 2017 – 20 March 2018
11136421 March 1985 – 20 March 1986139721 March 2018 – 20 March 2019
12136521 March 1986 – 20 March 1987139821 March 2019 – 19 March 2020
131366*21 March 1987 – 20 March 19881399*20 March 2020 – 20 March 2021
14136721 March 1988 – 20 March 1989140021 March 2021 – 20 March 2022
15136821 March 1989 – 20 March 1990140121 March 2022 – 20 March 2023
16136921 March 1990 – 20 March 1991140221 March 2023 – 19 March 2024
171370*21 March 1991 – 20 March 19921403*20 March 2024 – 20 March 2025
18137121 March 1992 – 20 March 1993140421 March 2025 – 20 March 2026
19137221 March 1993 – 20 March 1994140521 March 2026 – 20 March 2027
20137321 March 1994 – 20 March 1995140621 March 2027 – 19 March 2028
21137421 March 1995 – 19 March 1996140720 March 2028 – 19 March 2029
221375*20 March 1996 – 20 March 19971408*20 March 2029 – 20 March 2030
23137621 March 1997 – 20 March 1998140921 March 2030 – 20 March 2031
24137721 March 1998 – 20 March 1999141021 March 2031 – 19 March 2032
25137821 March 1999 – 19 March 2000141120 March 2032 – 19 March 2033
261379*20 March 2000 – 20 March 20011412*20 March 2033 – 20 March 2034
27138021 March 2001 – 20 March 2002141321 March 2034 – 20 March 2035
28138121 March 2002 – 20 March 2003141421 March 2035 – 19 March 2036
29138221 March 2003 – 19 March 2004141520 March 2036 – 19 March 2037
301383*20 March 2004 – 20 March 20051416*20 March 2037 – 20 March 2038
31138421 March 2005 – 20 March 2006141721 March 2038 – 20 March 2039
32138521 March 2006 – 20 March 2007141821 March 2039 – 19 March 2040
33138621 March 2007 – 19 March 2008141920 March 2040 – 19 March 2041

Accuracy

Its determination of the start of each year is astronomically accurate year-to-year as opposed to the more fixed Gregorian or Common Era calendar which, averaged out, has the same year length, achieving the same accuracy (a more simply patterned calendar of 365 days for three consecutive years plus an extra day in the next year, save for exceptions to the latter in three out of every four centuries). The start of the year and its number of days remain fixed to one of the two equinoxes, the astronomically important days when day and night each have the same duration. It results in less variability of all celestial bodies when comparing a specific calendar date from one year to others.[16]

Time of the vernal equinox relative to the start of the year for the (astronomical) Solar Hijri calendar, with 29-year, 33-year and 37-year subcycles marked

Birashk leap year algorithm

Iranian mathematician Ahmad Birashk (1907–2002) proposed an alternative means of determining leap years. Birashk's book came out in 1993, and his algorithm was based on the same apparently erroneous presumptions as used by Zabih Behruz in his book from 1952.[16] Birashk's technique avoids the need to determine the moment of the astronomical equinox, replacing it with a very complex leap year structure. 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 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.

The accuracy of the system proposed by Birashk and other recent authors, such as Zabih Behruz, has been thoroughly refuted and shown to be less precise than the traditional 33-year cycle.[16]

Each 2820-year great grand cycle proposed by Birashk 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. This average is just 0.00000026 (2.6×10−7) of a day shorter than Newcomb's value for the mean tropical year of 365.24219878 days, but differs considerably more from the mean vernal equinox year of 365.242362 days, which means that the new year, intended to fall on the vernal equinox, would drift by half a day over the course of a cycle.[16]

See also

Notes

  1. ^ Also called in some English sources as Iranian Hijri calendar.'[1]

References

  1. ^ a b c d ""Calendars" in Encyclopaedia Iranica". Iranicaonline.org. Retrieved 11 August 2012.
  2. ^ "دقیق ترین تقویم جهان، هدیه خیام به ایرانیان" [The most accurate calendar in the world, Khayyam's gift to Iranians]. BBC Persian service (in Persian). Bbc.co.uk. Retrieved 6 July 2013.
  3. ^ "پيمانه کردن سال و ماه از ديرباز تا کنون در گفتگو با دکتر ايرج ملک پور" [Measuring the year and month for a long time until now in a conversation with Dr. Iraj Malekpour]. BBC Persian service (in Persian). Bbc.co.uk. Retrieved 6 July 2013.
  4. ^ "پژوهش‌های ایرانی | پاسداشت گاهشماری ایرانی" [Iranian Studies & # 124; Preservation of the Iranian calendar]. Ghiasabadi.com. 3 November 2005. Retrieved 6 July 2013.
  5. ^ "پژوهش‌های ایرانی | گاهشماری تقویم جلالی" [Iranian Studies & # 124; Glory Calendar Timeline]. Ghiasabadi.com. 25 September 2007. Retrieved 6 July 2013.
  6. ^ Shaikh, Fazlur Rehman (2001). Chronology of Prophetic Events. London: Ta-Ha Publishers Ltd. pp. 51–52.
  7. ^ Marom, Roy (Fall 2017). "Approaches to the Research of Early Islam: The Hijrah in Western Historiography". Jamma'a. 23: vii.
  8. ^ Fazlur Rehman Shaikh, Chronology of Prophetic Events (London: Ta-Ha Publishers Ltd., 2001), p. 157.
  9. ^ Molavi, Afshin; Mawlawī, Afšīn (2002). Persian Pilgrimages by Afshin Molavi. ISBN 9780393051193. Retrieved 11 August 2012.
  10. ^ Gannon, Kathy. "The AP Interview: Taliban pledge all girls in schools soon". The Washington Post. Retrieved 15 January 2022.
  11. ^ "Why Afghans Don't Know Their Ages". NBC News.
  12. ^ Debbie Nevins (2020). Tajikistan. Cavendish Square Publishing. p. 118.
  13. ^ WERYHO, JAN W. (1994). "Tajiki Persian as a Europeanised Oriental Language". Islamic Studies. 33 (2/3): 341–373. JSTOR 20840172 – via JSTOR.
  14. ^ Holger Oertel (30 May 2009). "Persian calendar by Holger Oertel". Ortelius.de. Archived from the original on 16 July 2012. Retrieved 11 August 2012.
  15. ^ The Persian calendar for 3000 years, (Kazimierz M Borkowski), Earth, Moon, and Planets, 74 (1996), No. 3, pp 223–230. Available at [1].
  16. ^ a b c d M. Heydari-Malayeri, A concise review of the Iranian calendar, Paris Observatory.

External links

Online calendars and converters
Programming

Media files used on this page

Flag of Iran.svg
Flag of Iran. The tricolor flag was introduced in 1906, but after the Islamic Revolution of 1979 the Arabic words 'Allahu akbar' ('God is great'), written in the Kufic script of the Qur'an and repeated 22 times, were added to the red and green strips where they border the white central strip and in the middle is the emblem of Iran (which is a stylized Persian alphabet of the Arabic word Allah ("God")).
The official ISIRI standard (translation at FotW) gives two slightly different methods of construction for the flag: a compass-and-straightedge construction used for File:Flag of Iran (official).svg, and a "simplified" construction sheet with rational numbers used for this file.
Ordibehesht 1383 calendar.jpg
Author/Creator: Behdad Esfahbod, Licence: CC BY 2.0
Iranian calendar.
Landline installation contract for private buildings, Tehran - 14 April 1910 (Persian).jpg
A Landline installation contract for private buildings published on April 14, 1910 in Tehran in Persian and French.main page on nlai.ir
The contract was drafted in Persian and French in five chapters, tariffs for telephone installation stated according to the distance, wire used and subscription fee from the telephone center to the desired location inside and outside the city of Tehran for as private use.
Jalaali Leap Year.svg
Author/Creator: Joel Bradshaw, Licence: CC BY-SA 4.0
Illustrates how the leap year in the Jalaali calendar works. Charts the amount of time from the beginning of the year (12:00am, 1 Farvadin, Tehran time) and the spring equinox for each year from A.D. 1750 to A.D. 2250 (Jalaali 1129-1629). Lengths of leap year cycles are indicated with by brackets below graph.

Intended for comparison with the analagous Gregorian chart (https://commons.wikimedia.org/wiki/File:Gregoriancalendarleap_solstice.svg), thus the date range in nice round Gregorian years.

Generated with R & ggplot2, minor cleanup in Inkscape. Data generated using node and jalaai-js.

Source code: https://commons.wikimedia.org/wiki/File:Gregoriancalendarleap_solstice.svg