One Ummat One Eid, Ramadan And One Laylati Alqadr
The case I made above is that as soon as the first moon is sighted anywhere in the world, that witness should be enough for all Muslims living in any part of the world. That is, as soon as they reach Maghrib (sunset) in their area they should consider moon sighted based on moon sighting witness given earlier in other part of the world. For example, if first moon sighted in Australia than after 5 hours their would be sunset in Pakistan. So Pakistanis should start new month based on witness from Australia that the moon was sighted there. Similarly, in UK the sunset would be after 9 hours. They can use the same witness from Australia to announce start of new month in their country. In the same manner, New York, USA which has a 14 hours time difference with Australia. They can also announce start of new month as soon as they have sunset based on the same witness from Australia. During Prophet Muhammad’s pbuh times it was not possible due to lack of technology and means of communication but now it is quite possible.
As NAdeem Sb said, there is model which can give 100% accuracy. There are several reasons for it. Secondly, give me any model for visibility which says Australia will see the moon first. For next 5 year, Australia will never sight the moon first. So there can never be same day. If Saudia start ramazan on monday, US will start on sunday while Australia will do it on tuesday. As ramazan cannot begin in the middle of day time. I agree to the point that lack of communication in old time was significant hurdle. As I said ealier, this is a non issue. Actual unity donot come from celebrating on same day but to understand and feel the pain of other muslims and help them out. South Asian muslims generally follow same day for starting and ending of lunar months but what sort of unity do we have among them? Focus on real issues than non issues.
You are right, first plans are made on paper and then sometimes it may take centuries to execute that plan. If you do not draw anything in paper than it will never be implemented. The key is creating awareness, it may take few decades or longer.