Moon-sighting in Islam: Which lunar phases are the most significant?

Sighting the crescent to determine when the holy month of Ramadan begins is not the only moonsighting which concerns Muslims.

The relevant committee continues to sight the moon towards the end of Ramadan to sight the crescent that determines the beginning of the month of Shawwal and Eid al-Fitr and to later determine it’s the month of Dhu al-Qidah which Dhu al-Hijjah, that has to do with pilgrimage and Eid al-Adha, follows.

These three months are what determine when Muslims fast, break fast and perform pilgrimage.

Saudi moon-sighter Abdullah al-Khudairy, the director of the observatory of Majmaah University in Hautat Sudair, said the crescent cannot be sighted if it sets before the sun, or of it sets after the sun within a certain timeframe in a certain place and if it happens that there’s an eclipse.

If the eclipse happens after the sun sets, it’s not possible to see the crescent, but if it happens and ends before the sun sets, sighting the crescent will depend on its location in relevance to the moon-sighter.

In one of his lectures in Shaqraa, Khudairy explained that the first lunar phase is the New Moon and it takes the moon 29 days, 12 hours, 44 minutes, and 2.8 seconds to complete one cycle of this phase. This is followed by the Waxing Crescent which resembles an inverted C then there is the First Quarter, also known as the Half Moon.

Afterwards there are the Waxing Gibbous, the Full Moon, when we see the entire illuminated portion of the moon, the Waning Gibbous, the Last Quarter, which is another Half Moon but the illuminated part is opposite of the First Quarter, and the Waning Crescent which begins on the 25th of the lunar month and lasts until the end of the month.

Khudairy also said that the Waning Crescent, which looks like the letter C, phase is what concerns the moon-sighter the most as he must follow up on it a while before the sun sets.

“The most important condition to be certain it’s a crescent is for the part of the moon opposing the sun to be illuminated from below and for this part to remain illuminated in the horizon after the sun sets,” he added.