Iran calculated DST dates

[Roozbeh Pournader]

On Wed, 2005-03-30 at 14:38 +0200, Oscar van Vlijmen wrote:
> It appears that the dates were calculated with the arithmetic 'Persian'
> calendar in mind. Since 1925 an astronomical calendar is in use, so I read.
> There is one day difference between these two calendar systems in the
> Gregorian year 2025, so there is one error in the list of DST rules for Iran
> if indeed the astronomical calendar system is used.
>
> The astronomical Iranian calendar has 1 Farvardin 1404 on 21 March 2025
> Gregorian, so DST on is per 22 March 2025 0:00, and 30 Shahrivar 1404 is on
> 21 September 2025 Gregorian, so DST off is per 22 September 2025 Gregorian.
> 
> The vernal equinox in 2025 Gregorian is at around 09:01 UTC on March 20, so
> around 12:27 Tehran 'solar' time. This is past 12:00, hence 1 Farvardin is
> on March 21.

As an Iranian, and somehow an expert in the Iranian calendar, I copy you
on all of those details.

This should be clearly fixed.

roozbeh