Um al-Qura Calendar 1.3.35

The Um al-Qura calendar code was originally developed by Abu Hadi in the early 1990s, approximately between 1992 and 1993 AD. It was publicly released on Arabic programming sites on February 9, 2001 CE. The purpose of this release was to safeguard the intellectual rights of the programmer, especially given that the code has been widely used and modified by various individuals, often without proper attribution or acknowledgment of its original source.

Regarding the Um al-Qura calendar itself, it is a lunar calendar based on astronomical calculations, and it serves as the official calendar of Saudi Arabia. The first edition of this calendar was issued in the year 1346 AH (1927 CE) by the government press in Makkah.

The data sources for the calendar include:

• From 1300 to 1419 AH: The initial phase involved creating a comparative version of the Um al-Qura calendar, which was published by the Ministry of Finance and National Economy and printed by the Government Press Service in Riyadh in 1413 AH.
• From 1420 to 1422 AH: The second phase of development.
• From 1423 to 1450 AH: The third phase involved the official issuance of the Um al-Qura calendar by the King Abdulaziz City for Science and Technology, specifically through its Institute for Computer and Electronics Research.
• From 1451 to 1600 AH: The Al-Mustafa Calendar program, another of Abu Hadi's astronomical applications, which contributed additional data and calculations relevant to lunar calendar determination.