بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ

Rulings on Sighting the Moon — In the Light of Hadith

“Hazrat ‘Abdullah ibn ‘Umar رضي الله عنه narrates that the Messenger of Allah ﷺ said: ‘Do not begin fasting for Ramadan until you see the moon, and do not end (the fast of Ramadan) until you see it. If the sky is cloudy, then complete thirty days of the month.’” (صحیح بخاری ، صحیح مسلم)

Clarification:
In the case of اختلاف المطالع (difference of horizons), if the moon is sighted in one place, it will not necessarily be valid for another location. This is supported by the Hadith narrated from Kurayb: Umm al-Fadl sent him to Sham to Mu‘awiyah رضي الله عنه. Kurayb mentioned that while in Sham, the moon of Ramadan was sighted on Friday night. At the end of the month, when he came to Madinah Munawwarah, ‘Abdullah ibn ‘Abbas رضي الله عنه asked him when the moon had been sighted. He replied that it was sighted on Friday night. Ibn ‘Abbas رضي الله عنه said: ‘We saw it on Saturday night, and we will not rely upon the sighting of the people of Sham, because Sham is far from Madinah and their horizons differ.’

It should be noted that Sham lies to the north (or toward the eastern side) of Madinah Munawwarah, and the distance between them is approximately seven hundred miles. This indicates that such a distance leads to اختلاف المطالع. Modern geographers also state that if, in a city, the moon is eight degrees above the horizon at sunset, it will remain visible for about thirty minutes after sunset. In such a case, the moon may also be visible in eastern cities up to approximately five hundred and sixty miles away, provided clouds do not obstruct it. Thus, roughly every seventy miles corresponds to a difference of about one degree in visibility.

Therefore, if the crescent is sighted in one city, it will also be considered sighted in those cities lying to its west; this principle is among the established rules of علم الہیئت (astronomy). Likewise, if the moon is sighted in a western city, its sighting will be valid for eastern regions up to about five hundred and sixty miles, and for western cities without restriction.

One Should Not Fast on the Day of Doubt:

“Hazrat ‘Ammar ibn Yasir رضي الله عنه narrates that whoever fasts on the day of doubt has disobeyed Abu al-Qasim (the Messenger of Allah ﷺ).” (سنن ابو داؤد ، جامع ترمذی ، سنن نسائی)

Clarification:
The “day of doubt” refers to the thirtieth of Sha‘ban, about which uncertainty may arise as to whether the moon was sighted the previous night. Fasting on this day merely on the assumption that it might be part of Ramadan is not permissible.

Fasting May Begin on the Testimony of a Single Muslim:

“Hazrat ‘Abdullah ibn ‘Umar رضي الله عنه narrates that people went out to sight the moon, and I informed the Prophet ﷺ that I had seen it. Thereupon, the Prophet ﷺ himself fasted and instructed the people to fast as well.” (سنن ابو داؤد)