We should rely on sighting of the moon, not on calculations

Is there a certain length of time that the new moon has to be in the sky?

If a Muslim moves to another country during Ramadan

It is permissible to use telescopes etc., but not calculations, to sight the new moon

Sighting the moon not following astronomical calculations

Combining two intentions in one fast – the issue of overlapping acts of worship

Taking Medication While Fasting

Prisoner having intercourse with Wife during the day in Ramadan