A Brief Introduction To The Islamic (Hijrah) Calendar

Muslims measure the passage of time using the Islamic (Hijrah) calendar.  This calendar has twelve lunar months, the beginnings and endings of which are determined by the sighting of the crescent moon.  Years are counted since the Hijrah, which is when the Prophet Muhammad migrated from Mecca to Madinah (approximately July 622 A.D.).

The Islamic calendar was first introduced by the close companion of the Prophet, 'Umar ibn Al-Khattab.  During his leadership of the Muslim community, in approximately 638 A.D., he consulted with his advisors in order to come to a decision regarding the various dating systems used at that time.  It was agreed that the most appropriate reference point for the Islamic calendar was the Hijrah, since it was an important turning point for the Muslim community.  After the emigration to Madinah (formerly known as Yathrib), the Muslims were able to organize and establish the first real Muslim "community," with social, political, and economic independence.  Life in Madinah allowed the Muslim community to mature and strengthen, and the people developed an entire society based on Islamic principles.

The Islamic calendar is the official calendar in many Muslim countries, especially Saudi Arabia. Other Muslim countries use the Gregorian calendar for civil purposes and only turn to the Islamic calendar for religious purposes.

The Islamic Calendar, which is based purely on lunar cycles, was first introduced in 638 C.E. by the close companion of the Prophet  and the second Caliph, `Umar ibn Al-KHaTTab (592-644 C.E.) RAA. He did it in an attempt to rationalize the various, at times conflicting, dating systems used during his time. `Umar consulted with his advisors on the starting date of the new Muslim chronology. It was finally agreed that the most appropriate reference point for the Islamic calendar was the Hijrah. The actual starting date for the Calendar was chosen (on the basis of purely lunar years, counting backwards) to be the first day of the first month (1 Muharram) of the year of the Hijrah. The Islamic (Hijrah) calendar (with dates that fall within the Muslim Era) is usually abbreviated A.H. in Western languages from the latinized Anno Hegirae, "in the year of the Hegira". Muharram 1, 1 A.H. corresponds to July 16, 622 C.E.

SPECIFICATION AND METHOD

The Islamic (Hijrah) year consists of twelve (purely lunar) months. They are: (1) Muharram; (2) Safar; (3) Rabiulawall; (4) Rabiulakhir; (5) Jamadilawal; (6) Jamadilakhir; (7) Rejab; (8) Syaaban; (9) Ramadhaan; (10) Syawal; (11) Zulkaedah; and (12) Zulhijjah.

The most important dates in the Islamic (Hijrah) year are: 1 Muharram (Islamic new year); 27 Rejab (Isra & Miraj); 1 RamaDHaan (first day of fasting); 17 Ramadhan (Nuzul Al-Qur'an); Last 10 days of Ramadhaan which include Laylatu al-Qadar; 1 Syawal (AidilFitri); 8-10 Zulhijjah (the Hajj to Makkah); and 10 Zulhijjah (Aidiladha). It is considered a divine command to use a (Hijrah) calendar with 12 (purely) lunar months without intercalation.

Since the Islamic calendar is purely lunar, as opposed to solar or luni-solar, the Muslim (Hijrah) year is shorter than the Gregorian year by about 11 days, and months in the Islamic (Hijrah) year are not related to seasons, which are fundamentally determined by the solar cycle. This means that important Muslim festivals, which always fall in the same Hijrah month, may occur in different seasons. For example, the Hajj and Ramdhaan. It is only over a 33 year cycle that lunar months take a complete turn and fall during the same season.

For religious reasons, the beginning of a Hijrah month is marked not by the start of a new moon, but by a physical (i.e., an actual human) sighting of the crescent moon at a given locale. From the Fiqhi standpoint, one may begin the fast in Ramdhaan, for example, based on "local" sighting (IKHTILAF AL-MATALE') or based on sighting anywhere in the Muslim World. Although different, both of these positions are valid Fiqhi positions.

Astronomically, some data are definitive and conclusive (i.e. the time of the BIRTH of a new moon). However, determining the VISIBILITY of the crescent is not as definitive or conclusive; rather it is dependent upon several factors, mostly optical in nature. This makes it difficult to produce (in advance) Islamic calendars that are reliable (in the sense that they are consistent with actual crescent visibility).

Efforts for obtaining an astronomical criterion for predicting the time of first lunar visibility go back the the Babylonian era, with significant improvements and work done later by Muslim and other scientists. These efforts have resulted in the development in a number of criteria for predicting first possible sighting of a crescent. However, there remains a measure of uncertainty associated with all criteria developed thus far. Moreover, there has been little work in the area of estimating crescent visibility on global (as opposed to local) scale. Until this happens, no Hijrah calendar software can be 100% reliable, and actual crescent sighting remains essential especially for fixing important dates such as the beginning of Ramadhaan and the two `iyds ("Hari Raya").

The slight differences in printed Islamic calendars, worldwide, can therefore be traced to two primary factors: (1) the absence of a global criterion for first visibility; and (2) the use of different visibility criterion (or method of calculation). Weather conditions and differences in the observer's location also explain why there are sometimes differences in the observances of Islamic dates, worldwide.

Readers interested in further information should consult Mohammad Ilyas' excellent book ``A Modern Guide to Astronomical Calculations of Islamic Calendar, Times & Qibla,'' Berita Publishing, 1984, (ISBN: 967-969-009-1). The book contains a thorough discussion of the Islamic calendrical system and related historical and scientific developments. It also presents an interesting proposal for a universal Islamic Calendar based on a global visibility criterion and the concept of a Lunar Day (or International Lunar Date Line).

Resources: Waleed A. Muhanna