When should one pray Isha and Fajr and stop eating for the fast (Imsak) while the sky remains bright from sunset until sunrise in northern Canada?

The time for the Isha prayer begins with the disappearance of the red twilight, and the time for the Fajr prayer begins with the appearance of the true dawn. The prayer times can be ascertained by the শরعي signs, or by following trustworthy individuals who are knowledgeable of the times. One can also rely on reliable calendars to determine prayer times and the beginning of fasting.