Does the time for Fajr prayer end with sunrise, and is it permissible to make it up an hour after its prescribed time, or with the Duha prayer?

The time for performing the Fajr prayer begins with the appearance of true dawn and ends with sunrise. Whoever misses the Fajr prayer without a valid excuse must make it up immediately and repent for it, bearing in mind that some scholars consider intentionally leaving it until its time expires to be an act of disbelief. As for whoever misses it due to an excuse, such as sleep or forgetfulness, they must make it up immediately upon remembering it; based on the saying of the Prophet, peace and blessings be upon him: "Whoever forgets a prayer or sleeps through it, its expiation is to pray it when he remembers it." It is not replaced by the Duha prayer or any other prayer; rather, it must be made up by a separate prayer with the intention of making up the obligatory Fajr prayer.