The times of the prayer are determined by the position of the sun, i.e. by defining the above in astronomically measurable terms.
However for countries above 48 degrees (including Britain), Fajr and Isha timings require some estimation as the twilight may persist between sunset and sunrise for certain months of the year.
In these months the sun does not go below the horizon by a sufficient amount and so there is no true night.
Under these circumstances Salahtimes uses the 1/7 rule method by default (for UK) to calculate the Fajr and Isha times respectively, although you can change this to an alternative method.
These are the 2 schools of thoughts for determining the start of Asar prayer times.
These 2 schools of thoughts use different criteria to determine the start of Asar prayer. They do not affect the timings of the other prayers.
Shafi: The start of Asar is when the shadow of any vertical object exceeds the length of an object.
Hanafi: The start of Asar is when the shadow of any vertical object exceeds twice the length of an object.
Usually Hanafi Asar time is approximately 1 hour later than Shafi Asar prayer time.
Prayer times are established through a rigorous calculation and formula that consider multiple factors, including the latitude and longitude of a specific location. Consequently, variations in prayer times can arise when different organizations use these calculations, resulting in approximations that may differ.
Additionally, in regions with high latitudes, discrepancies in prayer times are even more pronounced, particularly during the summer months.
As a result, the introduction of the high latitude method became necessary to provide a practical approximation.
