Moon sighting practice explained: How Muslims determine the start of Ramadan
From naked-eye sightings to scientific input, faith and astronomy unite
Dubai: The sighting of the crescent moon, known in Arabic as “Ru’yat Al Hilal”, is the traditional Islamic practice used to mark the beginning of a new month in the Hijri calendar, most notably the start of Ramadan, and Shawwal, which signals Eid Al Fitr.
The process takes place on the 29th day of the current lunar month. As Islamic months last either 29 or 30 days, observers look towards the western horizon shortly after sunset in search of the faint, young crescent. If it is seen, the new month begins the following day. If not, whether due to cloud cover or because the moon sets before the sun, the month is completed as 30 days.
The astronomical new moon, when the moon is positioned between the Earth and the sun, is invisible. The religiously significant moment is the appearance of the first visible crescent, which may emerge hours later and remains visible only briefly after sunset.
Traditionally, sighting is conducted with the naked eye. However, telescopes and binoculars are increasingly used to assist observers, particularly when visibility is poor. In many countries, including the UAE and Saudi Arabia, official moonsighting committees convene on the 29th of Shaaban to verify testimony from accredited observers before issuing a formal announcement of the start of Ramadan.
Modern astronomical calculations now play a growing role. Scientific data can determine whether sighting is physically possible in a given location. If experts confirm that the moon would have set before the sun, many councils reject any claims of visibility.
Regional differences can result in varying start dates, as a sighting in one part of the world may not be valid elsewhere due to differing horizons. Scholars continue to debate whether Muslims should follow a single global announcement or rely on local sightings.
In practice, moonsighting represents a blend of religious tradition, scientific assessment and official verification, marking the beginning of sacred time in the Islamic calendar.
