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The Solar calendar ( fa, گاه‌شماری هجری خورشیدی, Gâhšomâri-ye Xoršidi; ps, لمريز لېږدیز کلیز, lamrez legdez kalhandara; ku, ڕۆژژمێری کۆچیی ھەتاوی, Salnameya Koçberiyê) is a
solar calendar A solar calendar is a calendar whose dates indicate the season or almost equivalently the apparent position of the Sun relative to the stars. The Gregorian calendar, widely accepted as a standard in the world, is an example of a solar calendar. ...
and one of the various ancient Iranian calendars. It begins on the
March equinox The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the ve ...
as determined by astronomical calculation for the
Iran Standard Time Iran Standard Time (IRST) or Iran Time (IT) is the time zone used in Iran. Iran uses a UTC offset UTC+03:30. IRST is defined by the 52.5 degrees east meridian, the same meridian which defines the Iranian calendar and is the official meridian of ...
meridian (52.5°E, UTC+03:30) and has years of 365 or 366 days. It is the modern principal calendar of both
Iran Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
and
Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is borde ...
, and is sometimes also called the Shamsi calendar, and abbreviated as SH, HS or, by analogy with AH, AHSh. The Ancient Iran Solar 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. It is older than the Lunar Hijri calendar used by the majority of
Muslims Muslims ( ar, المسلمون, , ) are people who adhere to Islam, a monotheistic religion belonging to the Abrahamic tradition. They consider the Quran, the foundational religious text of Islam, to be the verbatim word of the God of Abrah ...
(known in the West as the
Islamic calendar The Hijri calendar ( ar, ٱلتَّقْوِيم ٱلْهِجْرِيّ, translit=al-taqwīm al-hijrī), also known in English as the Muslim calendar and Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 ...
): the
Hijrah The Hijrah or Hijra () was the journey of the Islamic prophet Muhammad and his followers from Mecca to Medina. The year in which the Hijrah took place is also identified as the epoch of the Lunar Hijri and Solar Hijri calendars; its date e ...
, the journey of the
Islamic prophet Prophets in Islam ( ar, الأنبياء في الإسلام, translit=al-ʾAnbiyāʾ fī al-ʾIslām) are individuals in Islam who are believed to spread God's message on Earth and to serve as models of ideal human behaviour. Some prophets ar ...
Muhammad Muhammad ( ar, مُحَمَّد;  570 – 8 June 632 CE) was an Arab religious, social, and political leader and the founder of Islam. According to Islamic doctrine, he was a prophet divinely inspired to preach and confirm the mon ...
and his followers from
Mecca Mecca (; officially Makkah al-Mukarramah, commonly shortened to Makkah ()) is a city and administrative center of the Mecca Province of Saudi Arabia, and the holiest city in Islam. It is inland from Jeddah on the Red Sea, in a narrow v ...
to
Medina Medina,, ', "the radiant city"; or , ', (), "the city" officially Al Madinah Al Munawwarah (, , Turkish: Medine-i Münevvere) and also commonly simplified as Madīnah or Madinah (, ), is the Holiest sites in Islam, second-holiest city in Islam, ...
in the year 622. 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 Zoroastrianism is an Iranian religion and one of the world's oldest organized faiths, based on the teachings of the Iranian-speaking prophet Zoroaster. It has a dualistic cosmology of good and evil within the framework of a monotheisti ...
names from the
Zoroastrian calendar Adherents of Zoroastrianism use three distinct versions of traditional calendars for liturgical purposes, all derived from medieval Iranian calendars and ultimately based on the Babylonian calendar as used in the Achaemenid empire. ''Qadim ...
– 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 year A leap year (also known as an intercalary year or bissextile year) is a calendar year that contains an additional day (or, in the case of a lunisolar calendar, a month) added to keep the calendar year synchronized with the astronomical year or ...
s. 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.


Structure


Epochal date

The calendar's
epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided ...
(first year) corresponds to ancient Iran to at least 500 BCE. This Solar calendar predates the lunar calendar and it was reset in 622 CE the ''
Hijrah The Hijrah or Hijra () was the journey of the Islamic prophet Muhammad and his followers from Mecca to Medina. The year in which the Hijrah took place is also identified as the epoch of the Lunar Hijri and Solar Hijri calendars; its date e ...
'', which the Islamic regime thinks is it’s “epoch” but as it is a
solar calendar A solar calendar is a calendar whose dates indicate the season or almost equivalently the apparent position of the Sun relative to the stars. The Gregorian calendar, widely accepted as a standard in the world, is an example of 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 The Jalali calendar is a solar calendar, was compiled during the reign of Jalaluddin Malik-Shah I of Seljuk by the order of Nizam al-Mulk and the place of observation were the cities of Isfahan (the capital of the Seljuks), Rey, and Nishapur. ...
, 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 March is the third month of the year in both the Julian and Gregorian calendars. It is the second of seven months to have a length of 31 days. In the Northern Hemisphere, the meteorological beginning of spring occurs on the first day of 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
apsides An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...
, becoming inverted after around 11 500 years.)


Leap years

The Iranian Solar 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 A tropical year or solar year (or tropical period) is the time that the Sun takes to return to the same position in the sky of a celestial body of the Solar System such as the Earth, completing a full cycle of seasons; for example, the time ...
(365.2422 days) and the mean interval between spring equinoxes (365.2424 days). These algorithms are not generally used (see
Accuracy Accuracy and precision are two measures of '' observational error''. ''Accuracy'' is how close a given set of measurements ( observations or readings) are to their '' true value'', while ''precision'' is how close the measurements are to each o ...
).


New Year's Day

The Ancient Iranian Solar calendar year begins at the start of spring in the
Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...
: on the midnight in the interval between the two consecutive solar noons that includes the instant of the
March equinox The March equinox or northward equinox is the equinox on the Earth when the subsolar point appears to leave the Southern Hemisphere and cross the celestial equator, heading northward as seen from Earth. The March equinox is known as the ve ...
. 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

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", ), ''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 (). ''Jom'e'' is sometimes referred to by the native Persian name, ''adineh'' (). 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

On 21 February 1911, the second
Iranian parliament The Islamic Consultative Assembly ( fa, مجلس شورای اسلامی, Majles-e Showrā-ye Eslāmī), also called the Iranian Parliament, the Iranian Majles (Arabicised spelling Majlis) or ICA, is the national legislative body of Iran. The Pa ...
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. The present Iranian calendar was legally adopted on 31 March 1925, under the early
Pahlavi dynasty The Pahlavi dynasty ( fa, دودمان پهلوی) was the last Iranian royal dynasty, ruling for almost 54 years between 1925 and 1979. The dynasty was founded by Reza Shah Pahlavi, a non-aristocratic Mazanderani soldier in modern times, who ...
. 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. During Islamic regime, this Iranian zoroasterian calendar was appropriated to have started with Hijra of Muhammad from Mecca to Medina in 622 CE. It also deprecated the 12-year cycles of the Chinese calendar, Chinese-Uighur calendar, which were not officially sanctioned but were commonly used. ;Earlier starting year (500 BC discovered and from 1975–1979 it was reset to its original date of 500 BC) In 1975, ancient Iranian scholars discovered that this solar calendar was in practice as early as the Achaemenid Era. Therefore, the Pahlavi Monarchy under the direction of 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 The Iranian Revolution ( fa, انقلاب ایران, Enqelâb-e Irân, ), also known as the Islamic Revolution ( fa, انقلاب اسلامی, Enqelâb-e Eslâmī), was a series of events that culminated in the overthrow of the Pahlavi dyna ...
in 1979, at which time the Islamic regime changed the calendar to Solar Hijri.


Afghanistan

Afghanistan legally adopted the official Jalali calendar in 1922 but with different month names. Afghanistan uses
Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...
names of the zodiacal signs; for example, the 1978
Saur Revolution The Saur Revolution or Sowr Revolution ( ps, د ثور انقلاب; prs, إنقلاب ثور), also known as the April Revolution or the April Coup, was staged on 27–28 April 1978 (, ) by the People's Democratic Party of Afghanistan (PDPA) ...
took place in the second month of the Solar Hijri calendar (Persian
Ordibehesht Ordibehesht‌ or Ardibehesht ( fa, اردیبهشت, ) is the second month of the Solar Hijri calendar, which is used officially in Iran and Afghanistan. It has 31 days and spans the months of April and May in the Gregorian calendar. The Afgha ...
; ''Saur'' is named after Taurus). The Solar Hijri calendar has been until recently the official calendar of the government of Afghanistan, and all national holidays and administrative issues have been fixed according to the Solar Hijri calendar. However the Taliban have imposed the lunar Hijri calendar on Afghanistan during both periods of their rule. Under the
Taliban The Taliban (; ps, طالبان, ṭālibān, lit=students or 'seekers'), which also refers to itself by its state (polity), state name, the Islamic Emirate of Afghanistan, is a Deobandi Islamic fundamentalism, Islamic fundamentalist, m ...
's first rule (1996–2001), the lunar Hijri calendar was imposed, thus changing the year overnight from 1375 to 1417. And in a change that became effective 30 July 2022 (the
Islamic New Year The Islamic New Year ( ar, رأس السنة الهجرية, '), also called the Hijri New Year, is the day that marks the beginning of a new lunar Hijri year, and is the day on which the year count is incremented. The first day of the Islamic ...
on the lunar Hijri calendar) the Taliban have once again imposed the lunar calendar. Thus the year once again leaped forward, this time from 1401 to 1444.


Tajikistan

Tajikistan Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...
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 1 January in the Gregorian calendar, which is also the case in other non-Persian speaking
Iranian Iranian may refer to: * Iran, a sovereign state * Iranian peoples, the speakers of the Iranian languages. The term Iranic peoples is also used for this term to distinguish the pan ethnic term from Iranian, used for the people of Iran * Iranian lan ...
or Turkic communities ranging from Eastern Europe to Western China. Tajikistan's capital,
Dushanbe Dushanbe ( tg, Душанбе, ; ; russian: Душанбе) is the capital and largest city of Tajikistan. , Dushanbe had a population of 863,400 and that population was largely Tajik. Until 1929, the city was known in Russian as Dyushambe (ru ...
, is taken from the Solar Hijri calendar and translates to "Monday" in Persian.


Comparison with Gregorian calendar

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


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 Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the or ...
calendar which, averaged out, has the same year length, achieving the same accuracy (a differently patterned calendar of 365 days for three consecutive years plus an extra day in the next year, save for three exceptions to the latter in a 400-year cycle). 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.M. Heydari-Malayeri
A concise review of the Iranian calendar
Paris Observatory.


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. 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. 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 A tropical year or solar year (or tropical period) is the time that the Sun takes to return to the same position in the sky of a celestial body of the Solar System such as the Earth, completing a full cycle of seasons; for example, the time ...
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.


See also

* List of observances set by the Solar Hijri calendar *
Arabic names of Gregorian months The Arabic names of the months of the Gregorian calendar are usually phonetic Arabic pronunciations of the corresponding month names used in European languages. An exception is the Syriac calendar used in Iraq and the Levant, whose month names a ...
*
Assyrian calendar Assyrian may refer to: * Assyrian people, the indigenous ethnic group of Mesopotamia. * Assyria, a major Mesopotamian kingdom and empire. ** Early Assyrian Period ** Old Assyrian Period ** Middle Assyrian Empire ** Neo-Assyrian Empire * Assyrian ...
* Babylonian calendar *
Hebrew calendar The Hebrew calendar ( he, הַלּוּחַ הָעִבְרִי, translit=HaLuah HaIvri), also called the Jewish calendar, is a lunisolar calendar used today for Jewish religious observance, and as an official calendar of the state of Israel ...
* Indian calendar * Iranian calendars *
Islamic calendar The Hijri calendar ( ar, ٱلتَّقْوِيم ٱلْهِجْرِيّ, translit=al-taqwīm al-hijrī), also known in English as the Muslim calendar and Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 ...
*
Jalali calendar The Jalali calendar is a solar calendar, was compiled during the reign of Jalaluddin Malik-Shah I of Seljuk by the order of Nizam al-Mulk and the place of observation were the cities of Isfahan (the capital of the Seljuks), Rey, and Nishapur. ...
* Pre-Islamic Arabian calendar * Rumi calendar *
Zoroastrian calendar Adherents of Zoroastrianism use three distinct versions of traditional calendars for liturgical purposes, all derived from medieval Iranian calendars and ultimately based on the Babylonian calendar as used in the Achaemenid empire. ''Qadim ...


Notes


References


External links


How the leap years are calculated


; Online calendars and converters
An online Persian (shamsi)/Gregorian/Islamic (hijri) date converter on http://www.iranchamber.com

Online Persian Calendar and converter from parstimes.com

Online Persian Calendar from aaahoo portal

GFDL Afghan Calendar with Gregorian, Hejrah-e shamsi and Hejrah-e qamari dates
; Programming
GPL Iranian Calendar in JavaScript

System.Globalization.PersianCalendar class documentation in MSDN Library
(The implementation of Persian Calendar in Microsoft .NET Framework 2.0)
Persian Zodiac a free, open source AIR application.
{{calendars Calendar eras Calendars * Specific calendars Time in Afghanistan ku:Salnameya Îranî tr:İran takvimi