Is it permissible to pray Isha 45 minutes after the Maghrib prayer?

The time for 'Isha begins with the disappearance of the red twilight and extends until midnight. This is the view of the majority of scholars. Specifying the beginning of 'Isha time by an hour or half an hour is not precise due to its variation depending on countries and seasons. What is relied upon is the disappearance of the redness from the horizon. If observation is difficult, then one should rely on accredited calendars. Praying before the disappearance of the red twilight is invalid unless there is a legitimate excuse, such as combining prayers during travel or illness.