When is it time to start fasting? Astronomers explain the start of Ramadan

Moonsighting is a tradition used for centuries to determine the start of fasting during the holy month of Ramadan.

(SOUNDBITE) (Arabic) PROFESSOR OF SUN AND SPACE RESEARCH AT NATIONAL RESEARCH INSTITUTE FOR ASTRONOMY AND GEOPHYSICS, YASSIR ABDEL FATTAH, SAYING: "The observation of the Ramadan crescent starts with a pure scientific and mathematical approach, through astronomical equations with which we observe the crescent, prayer times, eclipses, and the direction of the prayer."

Ramadan is the first day of the ninth month of the Islamic lunar calendar.

Every year scientists and amateur astronomers gather across the Arab world to look for the new crescent moon.

(SOUNDBITE) (Arabic) DOCTOR AT MAJMAH UNIVERSITY, MOHAMMED AL-KHAMESI, SAYING: "I am now aiming the telescope at the sun, so I can adjust the focus and the angular distance, also I installed a CCD camera on it, you can see it on the laptop so I can make sure the focus is okay and then I can aim it at the moon until sunset."