The Makkah Calendar calculations are based on the new moon birth data provided by the US Naval Observatory and on Visibility Curves which are based on Yallop’s algorithm for predicted visibility of the young crescent. This algorithm has been much improved upon by Syed Khalid Shaukat from Washington, USA. The visibility curves we have used have been provided by him.
There follows a simple explanation of Makkah Calendar calculation methodology.
- On the evening of the day of the birth of the new moon, scrutinise if the new crescent is visible in Makkah [Makkah should be either in the green or in the blue zone of the Visibility Curves]. In that case, the new month will start on next day.
- If the new moon is not visible at Makkah, slide towards the west, further and further west of Makkah to scrutinise if the crescent is visible there. One obvious question which comes to the mind is where and when one should stop? The answer is: slide until it is time for the morning prayer (fajr
) in Makkah.
- If the crescent is visible before fajr in Makkah, we consider the visibility as visibility referred to Makkah itself. The new month will start on next day. We call this concept extended visibility.
- If the crescent is not visible until fajr in Makkah, then we move on to the next day and repeat the above process.
Please read the Makkah Calendar introduction
section to get a more detailed description of the Makkah Calendar calculation methodology. If you still have questions, please feel free to write us on [email protected]