For a Real Islamic Calendar...

This is a weekly post by Nidhal Guessoum (see his earlier posts here). Nidhal is an astrophysicist and Professor of Physics at American University of Sharjah.


In my previous post, I described why each year, as Ramadan nears it start (or end), the Muslim world witnesses a widespread confusion over what should actually be a matter of calendar construction. I also described the various complications (telescopes, CCD) that have recently been added to the problem. Finally, I explained that the real issue is the jurists – and many in the general population – who insist on sticking to traditional approaches by putting them squarely on religious (Sunna) footing. I concluded my post by stating that the solution lies elsewhere, i.e. really back to the calendar nature of the problem; I wrote: “So what’s the solution to this state of affairs? An Islamic calendar, of course, which I’ll discuss next time.”

It’s not like the Muslim world has never had an Islamic Calendar. In fact, the idea and practice of a calendar in the Islamic nation goes back to the earliest days, since the Hijri calendar was established by the (second) caliph Umar, who took office only two years after the death of Prophet Muhammad. The nature of the calendar (lunar, with no intercalation month) itself goes back to the Prophet and the Qur’an.

The earliest great Muslim astronomers, particularly Al-Battani (850-929) devised the “arithmetic” calendar, which was based on the simple following arithmetic rule:

• Months must alternate between 30 and 29 days;
• One day is added to some of the 12^th months, so that those (leap) years then have 355 days,; this is done so as to keep as much concordance as possible between the starts of the months according to this calendar and the appearance of the new crescents month after month;
• The leap years are those that satisfy the following rule: the remainder of the division of the year’s number (e.g. 1428) by 30 must be 2, 5, 7, 10, 13, 16, 18, 21, 24, 26, or 29. (For example the division of 1428 by 30 gives 47 with a remainder of 18, so 1428 is a leap year in this calendar).

With this rule, the average number of days in a month (averaged over 30 years) is 29.53 days, which is exactly the average number of days in between two new moons or two full moons. This calendar was first implemented by the Fatimide caliph Al-Hakim (985-1021). However, this calendar was used for “civil” purposes only (payment of salaries and such), not for “religious” ones, because it was obvious that it was often contradicted by the actual observations of the new crescent; it continued to be used until late in the 20^th century.

Saudi Arabia, which to my knowledge is the only country today to use a hijri/lunar calendar for civil purposes (all others use the Gregorian one), implements a different one, the “Umm al-Qura” (another name for Mecca) calendar, which has existed since 1950, and which rule was changed in 1998 and again in 2002, basically checking for the time of the lunar conjunction and the relative settings of the moon and the sun on the eve of the new month.

Such calendars carry the huge defect of being not very concordant with crescent sightings, which is why they are not used for religious purposes. Actually, this is only a minor reason, and is important only for people like me who are convinced of the necessity of implementing a calendar for both civil and religious purposes. The major reason is, as mentioned above, the refusal of many (including the overwhelming majority of Muslim jurists, most of whom are traditionalists) to do away with the practice of waiting until the eve of Ramadan (and other holy occasions) to ascertain the start of the month by someone actually sighting the crescent.

But at least to remove the minor problem (the lack of concordance between the calendar’s dates and the crescent observations), several astronomers  (Muslim and non-Muslims) have proposed calendar constructions that could solve the problem fully and globally, for they would not only tell people when each month will start, the dates would be confirmed by actual sighting – for those who would want to go check.

Astronomers like the Malaysian Ilyas, the British McNaughton, the Moroccan Abdurrazik, the Pakistani-American Shaukat, the Jordanian Odeh, and myself, have proposed various constructs. Deliberations (in meetings and conferences) over the past decade or so have led to a “convergence” toward two different solutions: the fully unified calendar of Abdurrazik and Shaukat, which proposes a single rule for the start of any month everywhere in the world; the bi-zonal calendar (Guessoum and Odeh), which splits the world into two large regions (the old continents and the new world) and devises two slightly differing calendars (which agree about 75 % of the time and differ by one day in other times).

It may seem obvious that the unified calendar is a better one – and hence to suggest a bi-zonal calendar seems superfluous – but there are pros and cons to each proposal: the unified calendar does not ensure enough compliance with the crescent’s visibility in the Islamic world, while the bi-zonal calendar gives up some of the unity but ensures (for the religious authorities) that the months so determined are almost fully in accordance with crescent observations.

And so if the problem is fully understood, and Muslim astronomers have labored hard and devised solutions, why is the Muslim world reluctant to adopt them? Because many still find it difficult to go beyond the old traditional ways of observing the crescent on “the night of doubt” in order to determine the start of the month. Once that mental block has been removed, the problem will be solved rather quickly and easily. But again, I must insist, to talk about a “civil calendar” that gets violated every time someone “sights” a crescent (or something) on the eve of a religious occasion is nonsensical. A real calendar is one that is used for all purposes. Today we are quite able to implement one; Islam has a chance to move forward and solve this serious, long-standing and disturbing socio-religious problem.