This has three major modern versions in use, Fasli ("seasonal"), Shenshai or Shahanshahi, and Qadimi ("ancient") which was adopted from the Irani (Persian/Jalaali?) calendar. The Qadimi is one month ahead of the Shenshai.
It has 12 named months (Mah) of 30 named days (Roz) each, divided into 4 weeks (two with 7 days, then two with 8 days). The names of the months are the same as some of the days, all being names of spiritual beings that preside over them. It is particularly sacred when the day and month are both presided over by the same spiritual being.
Months:
Days (with week divisions):
These 360 named days are then followed by 5 festival days. I don't know as yet the names, if any, given to these days.
The Fasli intercalculates one day every four years [similar to the Gregorian leap-day] to keep in harmony with the seasons, but I'm not as yet sure where this day is inserted. By use of this system, New Year's Day (Noruz or Naw Ruz) is fixed as the day following the Vernal Equinox.
I've cross-referenced the Fasli calendar in my perpetual calendar with several other solar calendars.
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