سوال

We are a new and small Muslim community from Regional Australia and 2 years back we just found a place for us to do our regular congregational prayers. So, you might be aware of like from other western countries, we are also having moon sighting issues. We Need your guidance who to follow and on what basis
Background: Australia is an island and non-Muslim state and have no inland neighbor country. Nearest one is either Indonesia or Malaysia over the ocean.
We have 3 groups in Australia all the Muslim almost follow. But none of them are any government bodies, they are communities   
1)  ANIC (Australia National Imam Council) completely relies on calculations and announced Eid and Ramadan a week before.
2) Moon Sighting Australia rely on local moon sighting only- Dr Shabbir is the coordinator
3) Islamic Society of Hollands Park. Brisbane relies on Regional Moon sighting with neighboring countries
So as a learner I have read the all-Madhab concept and quite clear about them and the few famous hadith as well.  So straight no to calculations as of my knowledge and understanding, am I correct? But when it comes to local and regional moon sightings, then we are bit confused about who to go with.
- Locals are quite clear that they only look within the Australia for sighting
- Regional Look for the neighbor Muslim countries for moon Sighting. So, for regional moon sighting do we have any distance (recommended) or time zone to look for. For example, that the Muslim country should be in that distance or time zone to be in regional moon sighting or any inland neighbor countries. Can we have some details and guidance please who to follow on what basis. Thanks

اَلجَوَابْ بِاسْمِ مُلْہِمِ الصَّوَابْ

In Islamic law (Shariah), the start of Ramadan and the two Eids depends entirely on the actual physical sighting of the new crescent moon (رویت بصری). Therefore, it is not religiously correct to rely solely on astronomical calculations to announce the dates definitively(حتمی) in advance, and this practice must be avoided.
Astronomy is only a supportive science. Its data can be analyzed to determine the best locations to look for the moon, to verify the statements of the people giving testimonies (شہادت), and to make initial forecasts (preliminary predictions) about the visibility of the crescent. However, a final decision cannot be made based on these calculations alone.
Furthermore, regarding moon sightings from other regions, Shariah has not set any fixed or rigid distance or time limits. The basic requirement is that the news from another area must be proven through authentic Islamic methods. These methods include، a trustworthy testimony, a testimony given on behalf of another witness's testimony (شہادۃ علی الشہادۃ), an authentic official notification of a Muslim judge's decision, or widespread reports (خبر مستفیض), which means receiving so many reports from different places that the authority gains absolute peace of mind and certainty (قلبی اطمینان).
Additionally, accepting a sighting from another area must not result in an Islamic month becoming 28 or 31 days long, because a lunar month can only be 29 or 30 days. It is also important to note that if the sky is overcast, the start of Ramadan can be announced based on just one truthful report, without requiring a full legal quorum of witnesses. However, for Eid, a full quorum of witnesses (کامل نصاب) is necessary if the weather is not clear. If the sky is clear, the testimony of a large crowd (جم غفیر) is required.
Since public affairs in Muslim countries are managed by the state, the decision of the government's official Central Moon Sighting Committee (رویت ہلال کمیٹی) will be the one to follow. In non-Muslim countries, a joint committee of authentic scholars takes the place of a government committee. If a unanimous (متفقہ) committee exists, its decision must be trusted. If there is no single unanimous committee, regular Muslims should follow whichever committee the majority of Muslims in that area trust, in order to prevent social division and confusion (انتشار). If multiple committees exist, the one following the most authentic Islamic method should be followed.
The committee is strictly required to fulfill all established Islamic procedures regarding moon sighting, Ramadan, and the Eids. They must make an effort for local sighting first. If they choose to follow another country's decision, they must fulfill all the Islamic conditions required to accept it. It must be clearly understood that if any committee makes an announcement based only on astronomical calculations, it is not permissible to follow their decision.

بدائع الصنائع(579/2)

قول النبي : وَصُومُوا لِرُؤْيَتِهِ، وَأَفْطِرُوا لِرُؤْيَتِهِ» ، أمر بالصوم والفطر : بعد الرؤية ...  لأن الشهر قد يكون ثلاثين يوماً، وقد يكون تسعة وعشرين يوماً؛ لقول النبي صلى الله عليه وسلم: «الشَّهْرُ هَكَذَا وَهَكَذَا»  وَأَشَارَ إِلَى جَمِيعِ أَصَابِعَ يَدَيْهِ، ثُمَّ قَالَ : الشَّهْرُ هَكَذَا وَهَكَذَا» ثَلَاثَاً، وَحَبَسَ إِبْهَامَهُ في المَرْةِ الثَّالِثَةِ ؛ فثبت أنّ الشهر قد يكون ثلاثين يوماً  ، وقد يكون تسعة وعشرين ... هذا إذا كانت المسافة بين البلدين قريبة لا تختلف فيها المطالع فأما إذا كانت / بعيدة ٢٠٤ب فلا يلزم أحد البلدين حكم الآخر؛ لأن مطالع البلاد عند المسافة الفاحشة تختلف، فيعتبر في أهل كل بلد مطالع بلدهم دون البلد الآخر .

تبیین الحقائق(165/2)

والأشبه أن يعتبر لأن كل قوم مخاطبون بما عندهم وانفصال الهلال عن شعاع الشمس يختلف باختلاف الأقطار، كما أن دخول الوقت وخروجه يختلف باختلاف الأقطار حتى إذا زالت الشمس في المشرق لا يلزم منه أن تزول في المغرب... وروي أن أبا موسى الضرير الفقيه صاحب المختصر قدم الإسكندرية فسئل عمن صعد على منارة الإسكندرية فيرى الشمس بزمان طويل بعد ما غربت عندهم في البلد أيحل له أن يفطر فقال : لا ويحل لأهل البلد لأن كلاً مخاطب بما عنده والدليل على اعتبار المطالع ما روي عن كريب أن أم الفضل بعثته إلى معاوية بالشام فقال : فقدمت الشام وقضيت حاجتها واستهل علي شهر رمضان وأنا بالشام فرأيت الهلال ليلة الجمعة ثم قدمت المدينة في آخر الشهر فسألني عبد بن عباس ثم ذكر الهلال فقال متى رأيتم الهلال فقلت رأيناه ليلة الجمعة فقال : أنت رأيته فقلت : نعم ورآه الناس وصاموا وصام معاوية فقال لكنا رأيناه ليلة السبت فلا نزال نصوم حتى نكمل ثلاثين أو نراه فقلت أو لا نكتفي برؤية معاوية وصيامه فقال : لا هكذا أمرنا رسول الله صلى الله عليه وسلم.