The Islamic calendar is a lunar calendar; it is based on the appearance of the first crescent moon to establish the starting date of a month. From this, the dates of Ramadan, Haj, and the Eids is established. Traditionally, the start of the month was triggered by the observation of that crescent moon by a man known to be honest and trustworthy. That is the system still used in Saudi Arabia and several other countries. The rest of the Islamic world has decided that astronomy and its mathematics is at least as trustworthy. Further, astronomical calculations are non-controversial: everyone can do the math and come to the same result.

The result of having two operating systems is that they sometimes conflict. While calculations will say that the month should start on Day X, weather or sky conditions may prevent a human from seeing the crescent moon on that day. For that observer – and the country that follows this system – the month might not start until X+1 or X+2. When communities were small and not really communicating with one another, this didn’t matter much.

Today, though, almost every part of the world is connected. People fly to attend Haj; they travel to spend Ramadan or the Eids with their families. Airlines rely on strict scheduling, run by math. If people are booking tickets to arrive on a particular day, the airlines are not capable of simply shifting the flights or the validity of the tickets, because their entire systems are rigid.

Saudi Gazette reports that the Muslim World League is sponsoring a conference in Mecca to try and sort out the issue. The purpose of the meeting is to unite the Islamic world, but I doubt that’s going to happen. The Saudi Grand Mufti has laid down his opening bid, saying that the traditional method has been the preferred method.

Conference on astronomical calculations begins in Makkah
Ahmad Wahaj Al-Siddiqui | Saudi Gazette

MAKKAH — A two-day Muslim World League conference on lunar months and astronomical calculations began here Saturday.

The conference is being attended by Sheikh Abdul Aziz Aal Al-Sheikh, Grand Mufti of the Kingdom, Sheikh Abdullah Bin Abdul Mohsin Al-Turki, Secretary General of MWL, Sheikh Saleh Bin Abdul Aziz Aal Al-Sheikh, Minister of Islamic Affairs, Call and Guidance, and scholars of other Muslim countries.

Al-Turki said the meeting had been called to deliberate on the issue of astronomical calculations. Scholars discussed if calculations could be used to unite the Muslim Ummah in determining the fast of Ramadan, Haj and the two Eids.
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