Context: The Solar Hijri calendar, also called the Shamsi Hijri calendar, and abbreviated as SH, is the official calendar of Iran and Afghanistan. It begins on the vernal equinox. Each of the twelve months corresponds with a zodiac sign. The first six months have 31 days, the next five have 30 days, and the last month has 29 days in usual years but 30 days in leap years. The year of Prophet Muhammad's migration to Medina (622 CE) is fixed as the first year of the calendar, and the New Year's Day always falls on the March equinox.

Question: What is another name for the Shamsi Hijri calender?
Answer: The Solar Hijri calendar

Question: What is one way to abbreviate the Solar Hiljri calender?
Answer: SH

Question: What is the customary calendar of Iran?
Answer: the Shamsi Hijri calendar

Question: How many months are in the Shamsi Hijri calendar?
Answer: twelve months

Question: What is the first year of the Shamsi Hijri Calender based on?
Answer: Prophet Muhammad's migration to Medina

Question: What is the modern name for the Solar Hijri calander?
Answer: Unanswerable

Question: What is the official calander of the Islamic world?
Answer: Unanswerable

Question: What calander ends on the vernal equinox?
Answer: Unanswerable

Question: What equinox does the calander end on?
Answer: Unanswerable

Question: What prophets year of birth marks the first year of the calander?
Answer: Unanswerable