The UAE's International Astronomy Center announced that the moon had set before the sun for all countries in the Muslim world on Friday, meaning that it could not have been seen on Friday night. The center noted, however, that Venus and Mercury had converged "very closely and strikingly" above the western horizon and may have caused some countries to believe that they were seeing the new moon.
Islam works on a lunar calendar with each day beginning in the evening. New months are declared when the moon's new crescent is sighted and can last either 29 or 30 days. The three-day Eid Al-Fitr holiday begins at the beginning of the month of Shawwal which comes after the fasting month of Ramadan.
According to Al-Araby, sightings of the new moon have long been debated among the global Muslim community, with controversy sparked by allegedly incorrect declarations concerning Ramadan and Eid Al-Fitr in the past by Saudi Arabia.
While Morocco, Somalia, Mauritania, Ethiopia, Senegal and Mali declared that they had sighted the new moon on Friday evening, Saudi Arabia did not declare a sighting, meaning that fasting continued for a 30th day in Saudi Arabia but ended after the 29th day in some African countries, according to Al-Araby. Many Muslims around the world follow Saudi Arabia's declarations on determining the new moons.
In comparison, according to the Jewish calendar, which is a 12-month lunar calendar that adjusts periodically with a 13th leap month to line up with the solar calendar, the month of Sivan began on Saturday night. Months in the Jewish calendar, similar to the Muslim calendar, last either 29 or 30 days and were declared by an actual observation of the new crescent of the moon in Jerusalem until the rabbis calculated a fixed calendar based on a number of astronomical calculations, ending the use of the empirical method of declaring new months.