Dr. Abdelhamid Bentchikou is a Biologist Engineer. He has both a Ph. D. in literature and in science. He was one of the founding deans of the University of Constantine, Algeria, from 1970 to 1975.
Dr. Moiz Rasiwala is an astrophysicist who obtained his Ph.D. in 1969 at the Institute of Astrophysics in Paris. He was at the National Centre of Scientific Research (CNRS) from 1963 until 1970. He was head of the physics department at the University of Constantine whilst Dr. Bentchikou was dean of the science faculty.
Mr. Amit Patel is a postgraduate in the field of Information Technology. He is currently working with India based top software services provider company. Amit is an executive engineer for Makkah Calendar Project.
This paper wants to shed a new light on the Islamic calendar for Makkah. This very practical problem has impact on the lives of millions of pilgrims across the world because the date of the Hajj, or the great annual pilgrimage, depends on an accurate calendar. Modern astronomical methods make it quite possible to establish an accurate calendar for Makkah decades in advance. This article enlarges upon the traditional Islamic idea of beginning the new month when the first crescent is observed in the evening sky, as reported by two reliable witnesses. The concept of the limiting horizon is introduced as defined by the time interval between sunset and the early morning prayer in Makkah at each birth of the new moon. Any visibility within the limiting horizon, at any intermediate horizon, is considered as visibility at Makkah itself.The concept of the limiting horizon permits the use of plotted visibility curves in order to predict the visibility of the early crescent to a high degree of accuracy. Some recent photographs of the early crescent are published in the article. They validate concretely the accuracy of our hypothesis.
Lunar calendars, just like solar calendars, are as ancient as the recorded history of civilisations. The only purely lunar calendar in use at present is the Islamic or Hegirian calendar (Hijri Calendar) in which the twelve months of the year follow twelve lunar cycles. Since the lunar year is shorter than the solar year by a period of 11 to 12 days, the Islamic months drift across the seasons in a cycle of approximately 33 lunar years.
Most other lunar calendars, the Hebrew, the Chinese, the Hindu calendars are in fact lunisolar calendars. To keep the months in phase with the seasons, even whilst accounting for the shortness of the lunar year with respect to the solar year, an intercalary 13th month is introduced every three years in general. These calendars are used essentially for religious purposes whereas the Hegirian calendar (Hijri calendar) is also the recognised commercial calendar in some Islamic countries like Saudi Arabia.
It is well known that the beginning of the Islamic month is based on the visibility of the earliest crescent moon as reported by two reliable witnesses. Thus, depending on local sighting, the calendar differs from one place to another. Amongst all the possible local Islamic calendars, that of Makkah is specially precious in order to determine the date of the annual pilgrimage. It concerns not only the Arabian peninsula but also the countries to the North, to the South and to the West of the peninsula. On certain months the calendar might also apply to the countries lying to the East. Thus it is essential to create a calendar for Makkah which is both totally scientific in nature and which respects Islamic tradition. In order to be useful, it must be possible to establish such a calendar over a long span of time depending on the predicted visibility of the New Moon.
The calendar of Makkah is not the universal Islamic Calendar / Hegirian calendar. But it can be a decisive step towards a universal calendar for Islam.
The highest authority in Islam is the Koran. Islamic law and tradition (the Sharia) are an expression of the Koran in legislative and social terms. A second authority is contained in the sayings and doings of the Prophet as recorded by a chain of reliable witnesses. These are known as the Hadith. Even in an article of scientific interest it is not irrelevant to reproduce some references to religious texts pertaining to the Islamic calendar. These texts are the ultimate authority in establishing a scientific Islamic calendar. We give the texts as an annex at the end of this article.
As remarked before, because of the varying visibility of the new crescent, each place in the world will have its own local calendar. In practice, however, each country will refer the calendar to the capital or some other important metropolitan town. The calendar thus used will be of a conventional nature.Conflict in fact can arise, and has arisen several times, between the conventional calendar and actual local observation.
We thus have the choice between observing the beginning of the Hegirian months from an agreed unique location – which seems rather difficult to admit – or, more broadly, by reference to a unique location.