There are different conventions for calculating prayer times. The following table lists several well-known conventions currently in use in various regions:
Method |
Abbr. |
Region Used |
Institute of Geophysics, University of Tehran |
Tehran |
Iran, Other Shia communities |
Shia Ithna Ashari, Leva Research Institute, Qum |
Jafari |
Shia communities worldwide |
Calculating Parameters
The table below shows the default calculating parameters for each calculation method:
Method |
FAJR Angle |
ISHA |
MAGHRIB |
Midnight |
Tehran |
17.7° |
14° |
4.5° |
Mid Sunset to Fajr |
Jafari |
16° |
14° |
4° |
Mid Sunset to Fajr |
We have got close to accurate time on the clock, reliable to follow for all regions, and tested in different region/locations with the help of volunteer teams across. However, the times are based on calculations only. Please allow +/- 3 minutes for Fajr, 1 minute for Dhuhr, and 2 minutes for Maghrib as a precaution.
Note: These timings are a general guideline, please use precaution and check your local timings for correct usage.
In the Shia's view, however, the obligatory precaution is that as long as the redness in the eastern sky appearing after sunset has not passed overhead, Maghrib prayer should not be performed. It is usually taken into consideration by assuming a twilight angle of 4 for Maghrib, i.e., Maghrib = Dhuhr + T(4).
Ref: http://praytimes.org/wiki/Calculation_Methods