The '''Iranian calendar''' {{Lang-fa|گاه شماری هجری خورشيدى}} also known as '''Persian calendar''' or the '''Jalāli Calendar''' is a [[solar calendar]]. It is currently used in [[Iran]] and [[Afghanistan]]. It is observation-based, rather than rule-based. Each year starts on the [[vernal equinox]] as precisely determined by astronomical observations from [[Tehran]] (or the 52.5°E [[Meridian (geography)|meridian]], which also defines [[Iran Standard Time|IRST]]) and [[Kabul]]. This makes it more accurate than the [[Gregorian Calendar]]. | The '''Iranian calendar''' {{Lang-fa|گاه شماری هجری خورشيدى}} also known as '''Persian calendar''' or the '''Jalāli Calendar''' is a [[solar calendar]]. It is currently used in [[Iran]] and [[Afghanistan]]. It is observation-based, rather than rule-based. Each year starts on the [[vernal equinox]] as precisely determined by astronomical observations from [[Tehran]] (or the 52.5°E [[Meridian (geography)|meridian]], which also defines [[Iran Standard Time|IRST]]) and [[Kabul]]. This makes it more accurate than the [[Gregorian Calendar]]. |