Regional sighting vs Global sighting:

Ahmad ad-Dardir, the noble jurist, mutakallim and Sufi from Egypt, wrote as follows in his super-commentary on Khalil’s Mukhtasar, Ash-Sharh al-Kabir:

“Fasting is generally binding on all the other countries, whether near or distant. No consideration is paid in that connection to whether the distance is such that a prayer can be shortened or whether the rising points of the moon (=start times of lunar days) are the same or differ. Fasting is incumbent on all those to whom a sighting has been transmitted.”

The one who sees the crescent vs the news of it reaching those who didn’t see it themselves:

Regional Sightings are established in two ways:

1. The one who sees the crescent himself is obligated to fast.
2. The one to whom the news of the sighting reaches, it is established by either,
   a) the testimony of two upright, male-witnesses, or
   b) news of the sighting reaches him through various independent sources eliminating the possibility of it being a concoction.

In the absence of a Qadhi/Imam or a Jama’ah that can establish these things, one can establish Ramadan by either:

1. hearing of a sighting from a trustworthy person, or
2. sighting the crescent oneself.

Global sightings are established in four ways:

1. News of the sighting is brought from a person who himself heard it from a trustworthy person.
2. By testimony of someone who heard the news of the sighting from another trustworthy person.
3. By someone who heard the news of the sighting from the testimony of another.
4. By means of testimony of someone based on the testimony of another person.

In all four cases, the judgement is the same: if the testimony, which is transmitted, is confirmed as being credible by the person in authority, like the Khalif or a local person in authority, then fasting is obligatory upon all those whom the news reaches and is not classed in the category of testimony. What’s important is that certainty be obtained and uncertainty removed.

Also radio, television, etc. are acceptable means for establishing a sighting from another region. [Ashal al-Masalik]

Following astronomical calculations:

Ibn Nafi’ narrates that Imam Malik said:

If an Imam does not fast according to the sighting of the crescent and does not break his fast according to the sighting of the crescent but instead relies on astronomical calculations then he is not to be followed or obeyed (in that regard).

Ahmad ad-Dardir said:

“The start of Ramadan is established either by completing the thirty-days of the month of Sha’ban or by the sighting of the crescent, not by astronomical calculations according to the mashhur because the legislator—Allah, Subhanahu wa Ta’ala—made the ruling dependent (only) on the sighting of the crescent or the completion of thirty-days for Sha’ban.”

Ahmad Zarruq said:

“It is apparent from his (ibn Abi Zayd) words that no attention should be given to those who follow astronomical calculations, and this is the truth.”

By Abdul Samad Ali