The Tonda family from Parmigiani Fleurier is an incredible range of timepieces that is known for its quality and exceptional design. The Tonda Heigirien uses the Muslim calendar, based on the cycles of the moon and consisting of twelve months of 29 or 30 days depending on the moon phase. This is used to pinpoint the days for Islamic holidays. In contrast to the solar calendar, which is used in the west, the months of the lunar calendar change annually by a difference of -10 to -12 days. As a result, each month always falls on a different season and therefore varies from the Gregorian Calendar.
