Question:
They say that what is currently practiced as the Subuh (Fajr) adhan is actually 15 minutes earlier than the real Fajr time, and that the real Fajr time comes 15 minutes later — calling that Subuh Sadiq (true dawn). What is the authenticity of this?
Answer:
Fajr and Subuh refer to the same prayer. This prayer has a start time and an end time.
What is the starting time?
When the eastern horizon becomes white. The sun sets in the west and rises in the east. About one hour before sunrise, a light appears in the eastern horizon — only in the lower part of the east; not everywhere in the sky.
When that light appears, that is what is referred to in Islamic law as Subuh. From that moment until sunrise, the Fajr time continues.
The light gradually increases. It spreads until half the sky becomes bright. When the sun actually rises, the brightness spreads fully.
The Prophetﷺ explained clearly about this, so, understand properly what is meant by the whitening of the east. Before the true dawn, about 15 minutes earlier, a vertical light appears in the sky — like a straight column of light. It looks like a vertical beam — like the English letter “I”. The Prophetﷺ said: Do not be deceived by that. The true dawn is not that vertical light. That vertical light disappears shortly afterward.
The true dawn is when the light spreads horizontally across the eastern horizon — from one end to the other — spreading along the lower horizon. When you look at the eastern base of the sky and see horizontal light spread across it, that is the true Subuh.
This is mentioned in Bukhari and Muslim (Hadith 1999).
The Prophetﷺ explained: Do not stop your pre-dawn meal (sahur) because Bilal gives the adhan. Bilal used to call the adhan earlier to wake people for sahur. Ibn Umm Maktum would give the adhan when the true Fajr time entered.
So, the vertical light (false dawn) should not deceive you. The horizontal spreading light (true dawn) marks the beginning of Fajr time.
Now someone has confused you saying: “The mosques give adhan at the false dawn; the real Fajr is 15 minutes later.” This is ignorance.
All mosques calculate Fajr time based on the horizontal spreading light — not the vertical one. All prayer timetables and apps also calculate according to the true dawn.
So, when mosques give the Fajr adhan, it is for Subuh Sadiq (true dawn), not false dawn.
There is no mistake in that.