Frequently Asked Questions (faq) - Search for 'twilight'

Muslims pray 5 times a day. The times of each prayer vary from place to place and from day to day. It is vital that Muslims perform these prayers at the correct time.

The 5 prayers are described below:

Fajr:
Starts at dawn or morning twilight
Ends just before sunrise

Zohar:
Starts at approximately 5 minutes after Zawaal
Ends at start of Asar time

Asar:
The start of Asar is dependant upon the length of the shadow that is cast by an object. Different schools use different criteria.
Ends just before sunset

Maghrib:
Starts at sunset
Ends at the start of Isha (i.e. when there is reddishness in the sky)

Isha:
Starts after dusk
Ends when the evening twilight disappears (i.e. when it first starts to get light)

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.

To determine Isha and Fajr calculations, one needs to calculate the time when the sun is at a certain distance below the horizon. The twilight angle is used for this purpose and it is defined as the angle in degrees of the sun below the horizon, when total darkness begins or ends.

Some organizations' use a fixed time after Maghrib to determine the start of Isha time.

Several standards have been established for determining Fajr and Isha prayer times.