The Hijri Calendar and its Conformance with the Gregorian Calendar by Mathematical Calculations

Description

This book is an expanded version of a research paper by the author on the Hijri calendar and its conformance with the Gregorian calendar, published by Matter International Journal of Science and Technology. Our objective for this work is to present a scientific study to the world, specifically the Islamic world, by establishing a Hijri calendar that conforms to the Gregorian calendar as there is not yet a robust work been done in this respect. The lunar months’ day is either 29 or 30 days, but this information used to be known only at the 29th day of the month by sighting the crescent appearance either by natural vision or by astronomical forecast. The basic information initiated this study is a verse from the Holy Quran in Sourat Alkahf, verse number (25) which states: “They remained in their cave for three hundred years, adding nine”. Irrespective of the story of this revelation we understand from it that every 300 solar years equivalent exactly to 309 lunar years. The first step based on this holy verse was to locate the number of days for each month of each lunar year, whether 30 or 29 days.