We can calculate the time of the major sunrise in one of two ways: The first method: We calculate the time from dawn to sunrise, then take half of it and subtract it from the time of noon, and the result will be the time of the major sunrise. For this, we need three pieces of information to calculate the time of the major sunrise: the time of dawn, the time of sunrise, and the time of noon. If, for example, dawn is at 4:07, sunrise is at 5:37, and noon is at 12:43, we say: the time from dawn to sunrise equals one and a half hours, which is 90 minutes, and half of that is 45 minutes. We subtract it from the time of noon, resulting in 11:58, which is the time of the major sunrise. The second method: Since the time of the major sunrise is half of the legal noon, we calculate the time from dawn to sunset - which are the two ends of the legal day - then we take half of it and add it to the time of dawn, resulting in the time of the major sunrise. If, for example, dawn is at 4:07 and sunset is at 7:49, the time between them is 15 hours and 47 minutes, and half of that is approximately 7 hours and 53 minutes. We add it to the time of dawn, resulting in 11:58, which is the time of the major sunrise.