Further observations may be made beyond what Shaykh al-Islam, may Allah have mercy on him, mentioned.
As for what can be seen, if you are in open country, with no surrounding lights to obstruct visibility and no haze, then when you see the whiteness stretching from north to south, dawn has broken and the time for prayer has begun. But before it becomes distinct, do not pray the dawn prayer.
His statement, “until sunrise”: the evidence for this is the hadith of Abdullah ibn Amr ibn al-As, recorded by Muslim (1) and others. From sunrise until the sun reaches its zenith is not a time for any obligatory prayer, just as the period from midnight until the break of dawn is not a time for any obligatory prayer, according to the sounder view (2).
Promptly performing it is better.
His statement, “Promptly performing it is better,” means that performing the dawn prayer at the beginning of its time is better. The evidence for this is as follows:
First: from the Quran: Allah the Exalted says, “So race to all that is good” [al-Baqarah: 148]; “And hasten towards forgiveness from your Lord” [Al Imran: 133]; and “Race towards forgiveness from your Lord” [al-Hadid: 21]. This is attained by hastening to perform acts of obedience.
Second: from the sunnah: the Messenger of Allah, peace and blessings be upon him, would pray it while it was still dark (3), and would finish it when a man could recognize the person sitting beside him. He would recite from sixty to one hundred verses (4), and the Prophet’s recitation, peace and blessings be upon him, was measured, pausing at the end of each