Solar Hijri calendar

For the lunar Hijri calendar used to date Islamic holidays and events, see Islamic calendar. For the Late Ottoman-era solar Hijri calendar, see Rumi calendar. For a succession of Iranian solar calendars, see Iranian calendars.

The Solar Hijri calendar (Persian: گاه‌شماری هجری خورشیدی‎‎, Pashto: لمريز لېږدیز کلیز‎), also called the Solar Hejri calendar[1] or Shamsi Hijri calendar, and abbreviated as SH, is the official calendar of Iran and Afghanistan. It begins on the vernal equinox as determined by astronomical calculation for the Iran Standard Time meridian (52.5°E or GMT+3.5h). This determination of starting moment is more accurate than the Gregorian calendar for predicting the date of the vernal equinox, because it uses astronomical observations rather than mathematical rules.[2]

Each of the twelve months corresponds with a zodiac sign. 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 New Year's Day always falls on the March equinox.

In Iran

On 21 February 1911, the second Persian parliament adopted as the official calendar of Iran the Jalālī 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 (Hegira of Muhammad from Mecca to Medina in 622 CE). It also deprecated the 12-year cycles of the Chinese-Uighur calendar which were not officially sanctioned but were commonly used.

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 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 vernal equinox and the autumnal equinox is about 186 days and 10 hours, the opposite duration about 178 days, 20 hours.

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 cycle with occasional interruptions by single 29-year or 37-year subcycles. The reason for this behaviour is (as explained above) that it tracks the observed vernal equinox. By contrast, some less accurate predictive algorithms are suggestion based on confusion between the average tropical year (365.2422 days, approximated with near 128-year cycles or 2820-year great cycles) and the mean interval between spring equinoxes (365.2424 days, approximated with a near 33-year cycle).

In 1976, Shah Mohammad Reza Pahlavi changed the origin of the calendar, using the beginning of Cyrus the Great's reign as the first day, rather than the Hejra of Muhammad. Overnight, the year changed from 1355 to 2535. The change lasted till the Islamic Revolution in Iran, 1979, at which time the calendar was reverted to Solar Hijri.[3]

In Afghanistan

Afghanistan legally adopted the official Jalali calendar in 1922[1] but with different month names. Afghanistan uses Arabic names of the zodiacal signs. The Solar Hijri calendar is the official calendar of the government of Afghanistan, and all national holidays and administrative issues are fixed according to the Solar Hijri calendar.

Details of the modern calendar

The Solar Hijri calendar year begins at the start of spring in the Northern Hemisphere: on the midnight between the two consecutive solar noons, which include the instant of the March equinox, when the sun enters the Northern Hemisphere. Hence, the first noon is on the last day of one calendar year and the second noon is on the first day (Nowruz) of the next year.

Month names

Order Days Iranian Persian Kurdish Afghan Persian (*) Afghan Pashto
Native Script Romanized Sorani Script Kurmanji Script Native Script Romanized Native Script Romanized
1 31 فروردین Farvardin خاکەلێوە Xakelêwe حمل Hamal (Aries) وری Wray (Aries)
2 31 اردیبهشت Ordibehesht گوڵان Gullan (Banemer) ثور Sawr (Taurus) غويی Ǧwayay (Taurus)
3 31 خرداد Khordad جۆزەردان Cozerdan جوزا Jawzā (Gemini) غبرګولی Ǧbargolay (Gemini)
4 31 تیر Tir پووشپەڕ Pûşper سرطان Saratān (Cancer) چنګاښ Čungāx̌ (Cancer)
5 31 امرداد) مرداد) Mordad گەلاوێژ Gelawêj اسد Asad (Leo) زمری Zmaray (Leo)
6 31 شهریور Shahrivar خەرمانان Xermanan سنبله Sonbola (Virgo) وږی Waǵay (Virgo)
7 30 مهر Mehr ڕەزبەر Rezber میزان Mizān (Libra) تله Təla (Libra)
8 30 آبان Aban گەڵاڕێزان Xezellwer (Gelarêzan) عقرب ‘Aqrab (Scorpio) لړم Laṛam (Scorpio)
9 30 آذر Azar سەرماوەز Sermawez قوس Qaws (Sagittarius) ليندۍ Līndəi (Sagittarius)
10 30 دی Dey بەفرانبار Befranbar جدی Jadi (Capricorn) مرغومی Marǧūmay (Capricorn)
11 30 بهمن Bahman ڕێبەندان Rêbendan دلو Dalvæ (Aquarius) سلواغه Salwāǧa (Aquarius)
12 29/30 اسفند Esfand ڕەشەمە Reşeme حوت Hūt (Pisces) كب Kab (Pisces)

The first day of the calendar year, Nowruz ("New Day"), is the greatest festival of the year in Iran, Afghanistan and surrounding 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 month names are the signs of Zodiac. They were used in Iran in early 20th century when the solar calendar was being used. The names are in fact the Arabic names for signs of Zodiac, please see دائرة البروج.

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.

Solar Hijri and Gregorian calendars

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 *)[4]

33-year
cycle[5] 		Solar Hijri year Gregorian year Solar Hijri year Gregorian year
1 1354* 21. March 1975 – 20. March 1976 1387* 20. March 2008 – 20. March 2009
2 1355 21. March 1976 – 20. March 1977 1388 21. March 2009 – 20. March 2010
3 1356 21. March 1977 – 20. March 1978 1389 21. March 2010 – 20. March 2011
4 1357 21. March 1978 – 20. March 1979 1390 21. March 2011 – 19. March 2012
5 1358* 21. March 1979 – 20. March 1980 1391* 20. March 2012 – 20. March 2013
6 1359 21. March 1980 – 20. March 1981 1392 21. March 2013 – 20. March 2014
7 1360 21. March 1981 – 20. March 1982 1393 21. March 2014 – 20. March 2015
8 1361 21. March 1982 – 20. March 1983 1394 21. March 2015 – 19. March 2016
9 1362* 21. March 1983 – 20. March 1984 1395* 20. March 2016 – 20. March 2017
10 1363 21. March 1984 – 20. March 1985 1396 21. March 2017 – 20. March 2018
11 1364 21. March 1985 – 20. March 1986 1397 21. March 2018 – 20. March 2019
12 1365 21. March 1986 – 20. March 1987 1398 21. March 2019 – 19. March 2020
13 1366* 21. March 1987 – 20. March 1988 1399* 20. March 2020 – 20. March 2021
14 1367 21. March 1988 – 20. March 1989 1400 21. March 2021 – 20. March 2022
15 1368 21. March 1989 – 20. March 1990 1401 21. March 2022 – 20. March 2023
16 1369 21. March 1990 – 20. March 1991 1402 21. March 2023 – 19. March 2024
17 1370*21. March 1991 – 20. March 1992 1403*20. March 2024 – 20. March 2025
18 1371 21. March 1992 – 20. March 1993 1404 21. March 2025 – 20. March 2026
19 1372 21. March 1993 – 20. March 1994 1405 21. March 2026 – 20. March 2027
20 1373 21. March 1994 – 20. March 1995 1406 21. March 2027 – 19. March 2028
21 1374 21. March 1995 – 19. March 1996 1407 20. March 2028 – 19. March 2029
22 1375*20. March 1996 – 20. March 1997 1408*20. March 2029 – 20. March 2030
23 1376 21. March 1997 – 20. March 1998 1409 21. March 2030 – 20. March 2031
24 1377 21. March 1998 – 20. March 1999 1410 21. March 2031 – 19. March 2032
25 1378 21. March 1999 – 19. March 2000 1411 20. March 2032 – 19. March 2033
26 1379* 20. March 2000 – 20. March 2001 1412* 20. March 2033 – 20. March 2034
27 1380 21. March 2001 – 20. March 2002 1413 21. March 2034 – 20. March 2035
28 1381 21. March 2002 – 20. March 2003 1414 21. March 2035 – 19. March 2036
29 1382 21. March 2003 – 19. March 2004 1415 20. March 2036 – 19. March 2037
30 1383* 20. March 2004 – 20. March 2005 1416* 20. March 2037 – 20. March 2038
31 1384 21. March 2005 – 20. March 2006 1417 21. March 2038 – 20. March 2039
32 1385 21. March 2006 – 20. March 2007 1418 21. March 2039 – 19. March 2040
33 1386 21. March 2007 – 19. March 2008 1419 20. March 2040 – 19. March 2041

Solar Hijri algorithmic calendar

The Solar Hijri (Persian) 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, but this makes it an observation based calendar.[6][7][8][9] Ahmad Birashk proposed an alternative means of determining leap years. His 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.

Accuracy

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. 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.[2]

See also

References

  1. 1 2 3 ""Calendars" in ''Encyclopaedia Iranica''". Iranicaonline.org. Retrieved 2012-08-11.
  2. 1 2 M. Heydari-Malayeri, A concise review of the Iranian calendar, Paris Observatory.
  3. ↑ Persian Pilgrimages by Afshin Molavi. Books.google.com. Retrieved 2012-08-11.
  4. ↑ Holger Oertel (30 May 2009). "Persian calendar by Holger Oertel". Ortelius.de. Retrieved 2012-08-11.
  5. ↑ The Persian calendar for 3000 years, (Kazimierz M Borkowski), Earth, Moon, and Planets, 74 (1996), No. 3, pp 223–230. Available at .
  6. ↑ "BBCPersian.com". Bbc.co.uk. Retrieved 2013-07-06.
  7. ↑ "BBCPersian.com". Bbc.co.uk. Retrieved 2013-07-06.
  8. ↑ "پژوهش‌های ایرانی | پاسداشت گاهشماری ایرانی". Ghiasabadi.com. Retrieved 2013-07-06.
  9. ↑ "پژوهش‌های ایرانی | گاهشماری تقویم جلالی". Ghiasabadi.com. Retrieved 2013-07-06.

Bibliography

Online calendars and converters
Programming
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