The sighting of the new Moon in a Country does not oblige all of the Countries to judge according to it
Question :
The appearance of the new moon of Ramadhan or the new moon of Shawwal varies between the Islamic countries. Therefore, do the Muslims fast when it is sighted in one of these countries?
Answer:
The people of knowledge differ among themselves on the issue of the new moon. Among them there are those who think that if the sighting of the new moon of Ramadhan is confirmed in any place in an Islamically sanctioned manner, then this obliges all of the Muslims to fast. They also say that if the sighting of the new moon of Shawwal is confirmed (in any place), all of the Muslims are obligated to break the fast.
This is the well-known view of the Mathhab (School of Fiqh) of Imam Ahmad. Based upon this, if the new moon is sighted in the Kingdom of Saudi Arabia, for example, it is obligatory on all of the Muslims in all of the lands to act according to this sighting in fasting Ramadhan and breaking the fast in Shawwal. The evidence that they use for this position is the generality of the Statement of Allâh, the Most High:
"So whoever among you witnesses the month, then let him fast it."
They also use the generality of the Prophet's statement:
"When you see it (the new moon of Ramadhan), then fast, and when you see it (the new moon of Shawwal), then break your fast."
Among the scholars are those who say that fasting with the new moon of Ramadhan and breaking the fast in Shawwal is not obligatory except for whoever sees the new moon or is in the same sighting zone (i.e., the same area of the sighting) as someone who saw it. This is because the rising points of the new moon differ, as is agreed upon by the people who know (its science). Thus, if the sighting zones differ, it is obligatory that every land judge according to its own sighting and the lands that are in the same sighting zone of the new moon should follow it. If a land is not in the same sighting zone, it should not follow another land's sighting. This statement is the one chosen by Shaykhul-Islam Ibn Taimiyyah, may Allâh have mercy on him. His proof for this view is in the Statement of Allâh, the Most High:
"So whoever among you witnesses the month, then let him fast it."
He also based this upon the Prophet's statement:
"When you see it (the new moon of Ramadhan), then fast, and when you see it (the new moon of Shawwal), then break your fast.
In other words, he used the same evidence that is used by those who hold the view that there is a general, comprehensive obligation regarding the ruling of the new moon. However, the angle of proof with Ibn Taimiyyah in this Verse and this Hadith is different, as (he held the view that) the ruling is related to one who witnesses and sees the moon. This dictates that whoever does not witness or see it, then he is not obligated to follow its judgement. Therefore, based on this, if the sighting zones differ, the judgements of the new moon are not confirmed by generalization.
There is no doubt that this is a strong position in proving this point and it is supported by examination and analogy.
Source:
Ash-Shaykh Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 3 Pages 232-233-234