Answered by Sidi Mostafa Azzam
Is it permissible in our school to pray Isha 50 minutes after maghrib? If so where does this ruling come from and are there any conditions? If it is not permissible, where might this misunderstanding have come from?
Isha time enters when the red twilight disappears from the sky. This varies from place to place and from season to season, and is not fixed to 50 minutes. Prayer timetables calculate isha according to the disappearance of the white twilight, which is later than the disappearance of the red. If one prays isha according to the prayer timetable, this is fine.
Mostafa Azzam