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The findings of historical research have not altered the usage of the accepted epoch date. The only variation normally encountered in normal usage is between the astronomical epoch and the civil. The astronomical epoch sets Anno Hegirae 1, Muharram 1 to A.D. 622 July 15, which is Julian Day 1,948,439. The civil epoch sets this date to one day later, A.D. 622 July 16, or Julian Day 1,948,440. The difference between the two dates arises because a new crescent is frequently not visible on the first day following a new moon, but only on the following day. Paleoastronomical calculations show that the astronomical New Moon (conjunction) occurred on A.D. 622 July 14 at 0444 hours. Thus, the first crescent occurred on 15 July but was probably not actually sighted until the evening of 16 July. The astronomical date is thus the technically correct one, although the civil date is the one actually used for most applications. The SCDTL system is issued with the civil epoch as its default. Like most calendars, the Islamic calendar was back-dated. Caliph Umar I is usually credited with establishing the Hijra Era, in A.H. 17 (A.D. 639). |
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9.3.1.2.3
Problems with a Lunar Calendar |
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Historically, the lunar character of the Islamic calendar has proven to be a problem for fiscal and administrative purposes, and Islamic governments have evolved a series of solar adaptations of various sorts with months from the Persian, Coptic, Julian, and other calendars. |
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The Persian Solar calendar is one example of such a calendar. Although based on the Hegira for its epoch, it calculates solar years and uses adaptations of older Persian month names. The SCDTL system contains a discussion of, and code for, this calendar. |
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An earlier adaptation was the Turkish Financial Year, or Maliye. The Ottoman Empire introduced this fiscal calendar for the purposes of revenue administration. The calendar is based on a Julian year structure, Syrian month names, the Hegira epoch, and a system of suppressing Hegira year numbers at intervals to keep the year numeration between the two calendars synchronized. In this section, I consider this calendar in some detail, since it illustrates certain problems associated with lunar calendars. |
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The government of Turkey introduced an adaptation of certain earlier fiscal calendars into the administration of revenues for the Ottoman empire. Philips claims (Handbook of Oriental History, p. 32) the year of A.D. 1789 for this introduction, although the more thorough article by Burnaby specifies (p. 471) 1 March 1676 (Julian). |
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The calendar essentially is an attempt to combine the Hegira era with a Julian solar calendar. Syrian names were used for most of the months. |
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