What is the ruling on one who does not fast Ramadan nor celebrate Eid until they sight the crescent moon with the naked eye, despite its sighting having been announced?

The preponderant view is that the establishment of lunar months depends on visual sighting, not on astronomical calculation, based on the Almighty's saying: "So whoever among you sights the moon (of the new month), he must observe Sawm (fasts) that month," and on the Prophet's (peace be upon him) saying: "Fast when you see it (the crescent moon), and break your fast when you see it." Juristic rulings are tied to criteria that are within the capacity of every accountable person. If a country relies on astronomical calculation, it should not be followed in this regard. Rather, the crescent moon should be sought by sighting; if it is sighted, they should fast, and if not, they should complete thirty days of Sha'ban. If sighting is not possible, they should fast and break their fast with the nearest Islamic country that relies on sighting. If you are in Madinah, reliance there is on visual sighting, and it is obligatory to fast and break fast with the rest of the people.