Persan Calendar

Many Indochinese civilizations based their calendar on the race of the moon. But the Persian cosmologists, the astronomers and the astrologers created in their time of the observatories, and daily followed the light change of solar luminosity.

The Persan calendar (or Iranian) is a solar calendar of use in particular in Iran since 1925 and in Afghanistan since 1957.
It goes down from the calendars zoroastriens of the pre-Islamic Perse. Its system of alternation of the normal years and the leap years makes it more precise than the Gregorian Calendrier.

Structure of the calendar

The year counts 365 or 366 days and is made up 12 months. The 6 first count 31 days, the 5 following 30 days and last month 29 or 30 jours.
The years are counted starting from the Hégire, that is to say the year 622 Gregorian calendar; however, dated July 16th, traditionally retained for Hégire, is replaced by that of the vernal equinox: 1st Farvardin of year 1 thus corresponds to March 21st, 622 of the Gregorian calendar. One also says that, contrary to the use in force in the Moslem countries Sunnite S, the Chiite S (Persan mainly) count their years starting from the Revelation of Gabriel to Mahomet, i.e. in 621 after J. - C.

Leap years

The system of leap years is more complex but as much more precise as the Gregorian system. It would have been set up by Omar Khayyam at the 11th century.
There is a 2820 years cycle of which 683 are bissextile. The intermediate duration of the year in such a cycle is 365,24219 days (against 365,2425 days in the Gregorian calendar) what is practically equal to the tropical year average, i.e. the period of revolution of the Earth around the Sun, which lasts 365,2422 days. The Persan calendar would thus cumulate a one day shift at the end one period of more than 2 million years.

Each 2820 years cycle breaks up as follows:

The years are numbered inside each period of 29,33 or 37 ans.
That is to say N the sequence number of the year during its time. The year is bissextile if these two conditions are checked:
N > 1 and N MOD 4 = 1

Months

The 12 months are in shift compared to the Gregorian calendar. The year starts with the vernal equinox, which corresponds in general to March 21st; the months thus are about fixed on cutting zodiacal of the year. Besides the months take the Arab name of the signs of the Zodiaque in Afghanistan while in Iran they have derived names divinities zoroastriennes.
The Iranian names below are given; the dates can vary slightly according to the effective date of the vernal equinox.

* has mordad, at the origin. The current form, devoted by the use, would mean on the contrary Mort .

History

At the time pre-Islamic, 365 days a solar calendar was already in force in Perse. The year counted 12 30 days months each one like 5 days additional. These 5 days in the beginning were inserted between 8th and the 9th month; as from the year millet approximately, they were moved with the end of the year.

Because of the 0,2422 days shift compared to the tropical year, the beginning of the year moved back one day every 4 years. The Arab caliphs Al-Mutawakkil (847-861) and Al-Mu' tadid (892-902) respectively proposed to shift of a blow the new year of 57 and 60 days, but none of these reforms seems to be respected.

In 1079, Djalal AD-DIN Malik Shah of the Seljuq refixa the new year with the vernal equinox. Before the system of the leap years is not fixed, Omar Khayyam (mathematician, astronomer and poet) had already proposed a 33 years cycle containing 8 leap years what increased the intermediate duration of the year to 365,2424 days, precision already higher than that of the Gregorian calendar.

It is into 1925 that the calendar in its current form became official in Iran, in 1957 in Afghanistan. This calendar is also of use in the close areas, in particular in the parts Kurdish S of the Mésopotamie.

In Iran, the passage to the New Year's Day is issued by the Institute of geophysics of Teheran: if, the day of the vernal equinox, the passage of the Sun at the equator, from a geocentric point of view, occurs before midday, Teheran time, it is the New Year's Day, if not the New Year's Day takes place the following day.

External bonds

Conversions/Calendars to Payvand.com bilateral Conversions between the calendars Gregorian and Persan. Dynamic generation of complete calendars. free Site.
Gregorian/Persan Calendar

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