|
|
|
|
|
|
|
In A.D. 1075, the Sultan Jelaledin Malik Shah bin Alkh Ashlan Suljookee of Persia decided to reform the Yazdagird calendar, to conform to the solar year. The result of consultation was a reform, which caused the New Year day to be moved from 26 February 1076 to 15 March 1076, the date of the vernal equinox. After this reform, it was realized that a new era was needed, to avoid disharmony between the lunar Hegira years and the new solar years. |
|
|
|
|
|
|
|
|
A committee of astronomers, led by the poet and astronomer 'Umar Khayyam, advised the sultan to institute an era bearing his name, and the vernal equinox of the year, falling in A.H. 471, was chosen as the epoch for the new era. This date was Friday, A.D. 1079 March 15, or A.Y. 448 Farvardin 19. The era was called the Jalali (Parise, p. 109; Taqizadeh 1940, p. 112) or Maliki (Taqizadeh 1940). This calendar ultimately fell into disuse. |
|
|
|
|
|
|
|
|
'Umar Khayyam is often credited with producing an extremely accurate calendar, by virtue of a complex leap year rule. Taqizadeh (1940, pp.113117) goes to some length to dispute this idea, arguing that the Jalalian year always began on the vernal equinox, with the consequence that the beginning of the year was determined by calculation every year. The New Year day was the day at the midday of which the Sun was already in the sign of Aries. It follows that each time the equinox occurred after noon, that day was a leap day, and the year coming to a close was a leap year (provided that this event occurred before noon the previous year). In other words, no rule for intercalation was necessary, and Taqizadeh claims that none was ever provided. |
|
|
|
|
|
|
|
|
See SCDTL text on the CD for the discussion of the code. |
|
|
|
|
|
|
|
|
9.8.3
Persian Solar Calendar |
|
|
|
|
|
|
|
|
The calendar called Persian Solar, or Iranian Solar, is the most modern form of a series of calendars that originated in Persia. |
|
|
|
|
|
|
|
|
Much of the information in this section was kindly provided by Mr. Hamed Eshraghian, whose code was used as the basis for the Julian Day conversion routines for this calendar. The conversion routines are the sine qua non of the suite of routines for any calendar. |
|
|
|
|
|
|
|
|
This section discusses the structural details of the Persian Solar calendar and introduces historical material as background. |
|
|
|
|
|