Difference between sunrise and break of dawn

Q: On behalf of the residents of Dawmah Al-Jandal Governorate located in Al-Jawf region, I ask you whether it is true that a time period of one hour and a half separates the break of the true dawn (the white line which penetrates the darkness of the horizon in the east) and sun rise. Is there any evidence from Shari`ah (Islamic law) to support that? Is it permissible to use a calendar to determine the time of Salah (Prayer)?Some people found that there is a time period of fifteen minutes. Some people of knowledge paid us a visit and said to us: "The Iqamah (call to start the Prayer) must be delayed by twenty-five minutes from the time of the Adhan (call to Prayer) in the calendar in order that the time of Salah is known to have approached." This means that both the Adhan and voluntary Salah offered before the obligatory Salah and Iqamah are offered before the appointed time. I have read the statement of Muhammad Rashid Rida (may Allah be merciful to him) in his Tafsir (exegesis of the meanings of the Qur'an) called "Tafsir Al-Manar", (vol. 2, p. 184; Dar Al-Ma`rifah edition). Commenting on the Ayah (Qur'anic verse) which reads: ...and eat and drink until appears to you distinct he said: "It is part of human nature that some individuals are prone to strictness while others are prone to negligence. Most people, however, adopt a moderate course between exaggeration and negligence. One of the things that proves that the ancestors went to extremes in taking care of outward appearance, yet ignoring the reformation of the inner souls is that (Part No. 5; Page No. 83) they would determine the starting time of Fajr by means of hours. As a means of precaution while observing Sawm (Fast), they would announce the Adhan (call to Prayer) of Fajr twenty minutes before its appointed time. As a matter of fact, daylight appears only twenty minutes after the break of Fajr. They delay the Adhan of Maghrib (Sunset) Prayer at least five minutes. Some of the Shi`ah (Shi'ites) stipulate the appearance of stars." He kept on stating this issue confirming that this increase should be as a means of drawing people's attention to be ready for the break of the dawn.We ask Allah that you will guide us so that we will apply the ruling you state. I stated earlier that some people of experience identify the time of Fajr by reference to the time period of one hour and a half before the sun has risen. Is there any proof for this?

A: Determining the appointed times of Salah is based on the Hadiths of the Prophet (peace be upon him). It was authentically reported that the appointed time of Zhuhr (Noon) Prayer starts when the sun begins to decline from its zenith and ends when the size of an object's shadow is equal to the size of that object. The appointed time of `Asr (Afternoon) Prayer starts when the shadow of everything becomes equal to itself and ends when it becomes twice its length or when the sun turns yellow. This is the optional time for offering `Asr Prayer. The appointed time of Maghrib Prayer starts from sunset until the twilight disappears. (Part No. 5; Page No. 84)  The appointed time of `Isha' (Night) Prayer starts from the disappearance of twilight until mid-night. This is the optional time for it. The time when it is necessary to offer `Isha' Prayer starts from mid-night until the break of dawn. The appointed time of Fajr Prayer starts from the break of the true dawn (i.e. the white line which penetrates the darkness of the horizon in the east) and continues until sunrise.These are the appointed times of the Five Obligatory Daily Prayers. The Muslim is duty bound to offer these Salahs at the times which have been stated by the Sunnah (whatever is reported from the Prophet). There is nothing wrong to refer to calendars if they happen to correspond to the appointed times of Salahs.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.