The mistake in duration is even bigger this year. Turkish Presidency of Religious Affairs (T.P.R.A.) claims this year, that fajr time is when the Sun is 18 degrees below the horizon. We have proven that the “Fajr-as Sadiq” occurs when the Sun is ten degrees below the horizon. ‘Five minutes’ times ‘eight degrees’ makes 40 minutes. This calculation changes this year, though. Because one degree takes almost six minutes in August. Besides, the sunrise time in T.P.R.A. calendar is at least seven minutes before the real sunrise time. Adding this seven minutes to the mistake of eight degrees, the total mistake in calendars approaches one hour.
The morning prayer should be performed at least one hour after the morning prayer adhan is heard in Turkey.
For details, please read the following article: