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Frequently Asked Questions

Why is Asr time incorrect?
There are two schools of thought for determining the start of Asr prayer time:

  • Hanafi
  • Shafe'i
Chances are that the method used by PrayerMinder is different from the one used for the prayer times you expect. You can try changing Asr time calculation method to see if it shows the time you expect.


Asr calculation methods
There are two schools of thought for determining the start of Asr prayer time:

  • Hanafi
  • Shafe'i
They are described in the next section.


Fiqh Hanafi and Fiqh Shafe'i

Start of Asr time is determined by measuring the length of shadow of an object, relative to the height of the object. The two schools of thought use these criteria to determine the start of Asr time:

  Fiqh Hanafi - shadow length = twice the length of object + shadow length at noon
  Fiqh Shafe'i - shadow length = length of object + shadow length at noon

Hanafi Asr time is about an hour later than the Shafe'i Asr time for most places.

Most people and places either follow one or the other of the methods, but there is also an opinion that one may pray both Zuhr and Asr prayers between the two Asr times.


Fajr/Isha calculation methods

According to Fiqh rules, Fajr and Isha times are determined when total darkness ends or starts, respectively. For automatic calculations, we determine the Fajr and Isha times by calculating the time when the sun is at a certain distance below the horizon. For this purpose we use the twilight angle, which is simply the angle in degrees of the sun below the horizon. Some places use a fixed time after sunset (Maghrib) as the start of Isha time.

Various standards for determining Fajr and Isha times are being practiced in the world today, as described in the next section.


Twilight Angle

Twilight is defined as the disappearing light after sunset, and the faint light before sunrise. Twilight angle is the angle of the sun below the horizon, when total darkness begins or ends. We use twilight angle to determine Fajr and Isha times programmatically.

The following standards for determining Fajr and Isha times are being practices in the world today:

OrganizationFajr - twilight angleIsha - twilight angleRegion
University of Islamic Sciences, Karachi1818Pakistan, Bangladesh, India, Afghanistan, parts of Europe
Islamic Society of North America (ISNA)1515Parts of USA & Canada, parts of UK
World Islamic League1817Europe, Far East, parts of USA
Um Ul-Qura, Makkah1990 mins after Maghrib, 120 mins during RamadhanArabian Peninsula
Egyptian General Organization of Surveying19.517.5Africa, Syria, Iraq, Lebanon, Malaysia, parts of USA

The above information was copied form Dr. Monzur Ahmed's page on determination of Salat times.


Total darkness does not occur

For greater latitudes (closer to North or South pole), during some summer days, the sun does not go far enough below the horizon for total darkness to occur. For those locations, PrayerMinder uses a smooth transition method to switch to 1/7th night rule for calculating Fajr and/or Isha time. The 1/7th night rule is described in the section below.


1/7th night rule

The 1/7th night rule is one of the several rules available in fiqh for determining Fajr and Isha times. This rule divides the total night between sunset and sunrise into seven parts; Isha starts when the first seventh part ends, and Fajr starts when the last seventh part starts.

For locations in greater latitudes, depending on the Fajr and Isha calculation method being used, if PrayerMinder determines that in summer days, total darkness will not happen, then it switches to using 1/7th night rule if the 1/7th night rule would give later Fajr time, and/or earlier Isha time. This method results in a smooth transition from the twilight angle method to the 1/7th night method. If the Fajr/Isha method specifies a fixed time after Maghrib for Isha, or a fixed time before sunrise for Fajr, then the 1/7th night rule is never applied.


Sun does not set

For extreme latitudes, during summer days, the sun does not set at all, and in winter the sun does not rise at all. During these days PrayerMinder divides the twenty-four hour period into two halves, and determines salat times by dividing the "day" and "night" halves into appropriate portions.


Qiblah finder's North

The Hand-held flavors of PrayerMinder have a handy Qiblah finder built-in. The Qiblah finder shows the direction of Qiblah relative to the direction of the sun. It also shows the direction of True / Celestial North Pole relative to the sun.

True North Pole is different from the Magnetic North Pole. A compass shows you the direction to the Magnetic North (or South) pole. Magnetic North Pole is not a fixed point on the earth's surface, and it drifts as time goes by. Therefore, PrayerMinder can only show True North Pole.

The difference between True North and Magnetic North is usually small, and probably within the error allowed for Qiblah determination for daily lives.

PrayerMinder's method of showing Qiblah direction relative to the sun is more accurate than using a compass because all qiblah direction tables actually specify qiblah direction relative to True North, but the compass shows Magnetic North.


Add more locations

Some hand-held flavors of PrayerMinder have a limited database of locations. The database contains ten locations. It is not possible to add more locations, but you can easily change any of the locations' data to the location for which you need prayer times.


Adjusting for Daylight Savings (Summer) time

The hand-held flavors of PrayerMinder can compensate for Daylight Savings (Summer) time. If your locality observes Daylight Savings time, then you can easily compensate for it during those days by checking the option for Daylight Savings by going into the current location's Modify dialog.



PrayerMinder prayer times have been compared with various other similar programs, and the difference has been found to be within three minutes or so. You should bear that in mind, especially for Maghrib prayers, and allow yourself for a few minutes of inaccuracy.