As is well known, for any given place, the new Islamic month begins when the young crescent moon is visible in the evening sky. Traditionally, the sighting is approved by the community if it is reported by two reliable witnesses.
What is true in general is of course true for the holy city of Makkah. The calendar of Makkah is particularly important because of the annual pilgrimage of Hajj, centred on this town. This pilgrimage draws millions of people from almost every country in the world. Thus it is particularly incumbent on the Saudi Arabian authorities to fix an accurate date each year for Hajj. Because of the place Makkah occupies in the conscience of every pious Muslim, it is equally important to fix accurately the two other major feast days of Islam: the beginning and end of the fasting month of Ramadan.
In our project of establishing an accurate scientific islamic calendar for Makkah based on the calculated and predicted visibility of the new moon, we have enlarged upon the notion of visibility in Makkah around the sunset that follows the birth of the new moon. Invisible at conjunction, the crescent cannot be seen until at least ten hours after this recurrent monthly event. However, instead of trying to spot the crescent in Makkah around sunset, it is perfectly legitimate to allow oneself more time and take into consideration the whole interval of time between sunset and the early morning prayer (fajr) on the following day.
In practice, we examine the status of the visibility of the crescent to the west of Makkah if there is no visibility in Makkah itself. If anywhere, on land, the crescent becomes visible before fajr in Makkah, we postulate this visibility as acquired in Makkah itself. We call this concept the concept of extended visibility.
For each new moon, if no sighting is possible in Makkah itself, we predict the sighting to the west of this locality on the basis of calculated and plotted visibility curves. These curves have been established by Syed Khalid Shaukat. The reader will find examples of these curves on Mr. Shaukat’s site www.moonsighting.com or on our site Makkah Islamic Calendar. On the basis of the predicted visibility of the crescent we have commissioned photographs from reliable observatories or individual astronomers in the USA, Canada, Argentina and so on. A remarkable series of young crescent photographs exists in the photo gallery of our site. These photographs are a clear proof of the accuracy of our visibility curves.
The reader will find an extensive development of what is said above in the introduction to our site as well as in its FAQ section. The more technically minded reader will find in the Announcements section of our site the reference to an Islamic Calendar Article recently published in a well known international scientific journal called Selenology Today.
Known as the Umm al-Qura calendar the Saudi Arabian Authorities uses the following criteria for determining the beginning of the Islamic month. These criteria apply since the Islamic year 1423 :
If on the 29th day of the lunar month the following two conditions are satisfied, then the next day is the first day of the new lunar month:
1. The geocentric conjunction occurs before sunset
2. The moon sets after the sun
Otherwise, the current month will last 30 days.
It is obvious that the actual sighting of the young crescent is not taken into account. Many discrepancies have been reported about the beginning of the lunar month under these circumstances. Even if the conjunction is shortly before sunset, with no possibility of viewing the crescent on that particular evening, the month will be declared as over, contrary to Islamic law.