4.4 Ikhtilaaf AlMatale is supported by Astronomy and by Scholars world wide including Saudi Arabia
Since the Earth is spherical, the Horizons are multiple (Ikhtilaf AlMatale) and Local sighting if Hilal is as natural as Local sighting of Sun (shadow) for local Prayer times. Shafi, Maliki and Hanabali Jurists support Ikhtilaaf AlMataale. (Ref.: Bidaytul Mujtahid v.1 of Imam Ibn Rushd (A Maliki Qadi, and a prominent Islamic philosopher, of Spain). While some of the early Hanafi jurists, at a time when it was thought that the Earth was flat, supported Ittihaad AlMatale, it was for short distances and not for the whole world. Today for example, in India, Pakistan and Bangladesh, where Hanafi Fiqh is dominant, Ittihaad AlMatale is not practiced. Saudi Arabia also practices Iktilaaf AlMataale as mentioned in this Fatwa by Sheikh AlOthaimeen (RH) in the book: Fatawa Islamiya (Sheikh Bin Baaz, Sheikh AlOthaimeen & Sheikh AlJibreen - DarulWatan LilNashr and reproduced below. Saudi Arabia itself follows Ikhtilaaf AlMataale, not even accepting sighting from next door Yemen!
One Islamic basis for Ikhtilaaf AlAMatale comes from “Hadith Kurayb (رضي الله عنه)” where the report of Hilal sighting from Damascus was not used by Ibn Abbas (رضي الله عنه) for Medina. Indeed calculations show that sometimes it is possible to see the Hilaal in Damascus and not in Medina!
The Hadith of Kurayb (may Allah be well pleased with him!):
[I saw the crescent [of Ramadan] on Friday night while in Damascus. I arrived at Medina at the end of the month and Ibn ‘Abbas (may Allah be well pleased with both of them!) asked me: “When did you see the crescent?” I said: “We saw it on Friday night.” He said: “Did you see it yourself?” I said: “Yes, and the people saw it, and they and Mu‘awiya fasted.” He said: “But we saw the crescent on Saturday night. So we will not stop fasting until either we complete thirty [days] or we sight the crescent [of Shawwal].” I said: “Is Mu‘awiya’s sighting and fasting not sufficient for us?” He said: “No, this is how the Messenger of Allah (may Allah’s blessings and peace be upon him!) ordered us.”] (Related by Ahmad, the Famous Five except al-Bukhari, and by al-Daraqutni and al-Bayhaqi, with variants).
Also, the Hadees 'We are Ummi we do not write or calculate' ends by saying 'month is 29 and 30'. 'Haakaza wa Haakaza'. So that means month will be 29 and 30 (in different places). The Hadees does not say 'Hakaza aw Hakaza' which would then mean month is 29 or 30.
Also following Fatwa supporting Ikhtilaaf AlMataale:
ISNA's Eid al-Adha Evaluated by A Renowned Scholar (Mufti Muhammad Taqi Usmani)