Quran and Hadees clearly declare the moon sighting, and not Calendar to begin and end the month. Quran says, “And that who witnesses the (moon of the) month should keep fast.”[1] Hadees from the Holy Prophet (s.a.w.a.) says, “Keep fast for sighting the moon, and end your fast (Eid) for sigthing the moon.” Moon sighting can be anywhere where night is common according to many Ulama e.g. Ayatollah Khoei, or common ‘Ufuq’ according to other Ulama e.g. Ayatullah Seestani. Following the calendar not based on moon sighting is a deviation from Shariat.   _{Your Comment}