Zhuhr (noon): The time for the zhuhr prayer begins when the entire sun disk has passed a vertical line suspended from the highest point of the sun during a day.
Asr (afternoon): There are two opinions regarding the start of Asr prayer:
Isha (night) has two definitions:
Principles of taqdir
At high latitudes, there are periods during the summer when the prayer times do not exist accoriding to the above definitions.
According to the Shafi`i and Maliki madhhab it is then obligatory to make an estimate (taqdir). In the Shafi`i madhhab the principle called "aqrab al-bilad" is applied. This means that during the critical period prayers are performed at the times of the nearest location where they still exist.
In the Hanafi madhhab salat is occasioned by the beginning of its time. According to Imam Abu Hanifa, it is not obligatory to perform the Isha prayer if its time does not occur [Ref]. However, later fuqaha, like Ibn `Abidin said in Radd al-Muhtar that it is still obligatory to pray Isha even when its time does not exist according to the definition [Ref]. In this case one has to apply taqdir. The classical Hanafi fiqh literature does not give detailed instruction on how to apply taqdir. However in recent times, fuqaha have suggested various methods, which either emulate other madhahib or are based directly on Hadith. This is discussed in detail in the section Implementation of taqdir.
Computing Shuruq and Maghrib
(sunrise and sunset)
Any calculation model needs to take into account the following factors:
Astronomical sunrise/sunset depression from zenith is 90°. In the Islamic context, the depression from the horizon is preferred, i.e. sunrise/sunset is when the sun is depressed 0° from the horizon. At this point, one would see the center of the sun disk passing through the horizon, when standing at a free horizon at sea level - if there were no atmosphere surrounding earth. However, sun rays passing through the atmosphere are deviated, due to the refraction of the air. Therefore the observer will see sunrise a little earlier and sunset a little later than the times calculated.
Most astronomical and metrological time tables compensate for this by adding a standard angle of 0.833°.
The Swedish Metrological Institute, SMHI [Ref, data] and Astronomisk kalender [Ref, data] sunrise and sunset as the astronomically compute time when the center of the sun disk is at the horizon, adjusted with an angle of 3.4´ (0.57°). It is not clear it this is meant to compensate for refraction alone or also for the passage of the disk through the horizon.
The astronomical calendar "Den Svenska Almanackan" uses a compensaiton of 0.833°, which is the international standard used also US Naval Observatory [Ref, data] and other observatories around the world. This is meant to compensate by 0.16´ (0.267°) for the apparent radius of the sun, plus 0.34´ for refraction, summing up to 0.5` (0.833° in decimals).
Compensation for refraction
At high latitudes, refraction has an essential effect on the observation of sunrise and sunset. It is therefore necessary to apply a more refined method than that used in presently available tables.
Most Islamic prayer time tables adopt the international standard of 0.57°, which was suggested by Bessel in 1823, which is not adequate at high latitudes. Tables published by IKUS for Scandinavia use an adjustment of 1.73°, which applies to extreme latitudes.
In Birka we have implemented a simple empirical model for the variation of refraction with latitude (see section on Refraction):
f(Lat) = 0.59 ln ( 1 - Latit / 78° )
Refraction aangles for locations at different latitudes
The table below shows the difference in sunset times obtained with and without refraction compensation at different latitudes. We can see that the standard compensation of 0.833° adds 4-5 minutes to sunset time. This is valid in London. In Stockholm the effect is 10 minutes, and in northern Sweden up to half an hour and more!
(*) indicates sun never setting, (**) indicates sun never rising,
(***) Note that, due to refraction, midnight sun can be seen for a few days in Luleå, even though it is loated south of the polar circle.
Islamic prayer time tables
We conclude from the above that the compensation used in the current prayer time tables is not adequate. The table below shows the calculated time for Maghrib varies depending on the compensation applied.
Taking Birka as the accurate norm, we see that tables applying the model of Bessel give Maghrib times up to 20 minutes ahead of the its time, while the IKUS model leads to Maghrib times up to 20 minutes past its time.
Computing Fajr and Isha
Astronomers use the following measures of darkness:
Relation between fiqh defintions and astronomical angles
According to the Egyptian Fatwa Authority (Fatwa No. 200750), the difference between the disappearance of the red and the white twilight corresponds to an angel of 3°.
Most Islamic prayer tie tables relate the fiqh definition of Fajr and Isha to an angle between 15° and 20°. Some commonly quoted value are shown below.
on August, 21, 2009, depending on the definition of twilight
In Makka, on August 21, the difference between 15° and 18° corresponds to a time difference on only 12 minutes, while in Stockholm it corresponds to one hour's difference (in the north of Sweden, twilight does not end at this date). From there we see that it is most important to use an accurate model for high latitudes. Such a model must be based on actual observation of the phenomena described by the fuqaha.
Angles deduced from observation of dawn and dusk
How to relate eye observation of Fajr and Isha to the angles used in calculations, and what needs to be considered in order to make generally valid observations - this is discussed in detailed in the section Observations. Below is a summary of angles obtained from various observations:
These values need to be taken with great caution, as many observations are likely to be affected by light contamination, making it impossible to observe a really dark sky - see the section Physical measures of darkness. The conservative route is to use the higher values in each category.
"Persistent twilight", midnight sun and polar night
"Persisting twilight" means that Isha and Fajr times do not exist according to their fiqh definitions. This occurs at high latitudes for a longer or shorter period during summer. This phenomenon is mentioned in the early Hanafi fiqh literature. The computed length of this period varies with latitude, and depends on which angles are adopted for Fajr and Isha.
Approaching the polar circle, sunset also disappears and the sun is stil visible at midnight (midnight sun). This is not mentioned in the classical fiqh literature.
Length of the period depending of twilight definition
The table below shows beginning and end of the persisting twilight period for locations at various latitudes, depending of which angle is used for Isha.
If, for instance, the angle 18° is used for Isha (corresponding to the end of the white twilight), the period in which Isha does not occur in Stockholm lasts from April 23 to August 18, and persistent twilight occurs down do latitude 49° (Paris). If instead 15° is used for Isha, the period will be three weeks shorter in Stockholm, and it will not occur at all south of latitude 51.5° (London).
Implementation of taqdir
When prayer times do not occur according to their definition, one may construe them (taqdir) according to the directions given by fuqaha. Taqdir is only to be used a way out when this is necessary, i.e. within the period when no time can be observed, not outside that period.
The Shafi'i madhhab rules the principle of "aqrab al-bilad", which meabs that prayer times are taken from the nearest location where the times still exist. The span of time between Maghrib and Isha at that location is added to the local Maghrib time. However, if this is applied on a day-to-day basis, the location that lent its time will soon lose it as well, so one has to move further south to find a new location where the times exist and repeat the same procedure [Ref]. Hence in practice, this implementation "aqrab al-bilad" amounts to setting Isha close to midnight (between sunset and sunrise) for the entire period.
In the Hanafi madhhab, if the white twilight is normally used, the red twilight can be used during the critical period, if it exists, since it is a valid alternative in the madhhab. When the red shafaq also persists, different methods of taqdir have been suggested by recent 'ulama in the Hanafi madhhab:
A combination of 3 and 1 is suggested by Nuh Keller in "The Reliance of the Traveller", namely to add the amount of time between Maghrib and Isha in the "nearest city" to the time of Maghrib in one's own city (and similarly for Fajr). However, this method crashes at high latitudes (e.g. in Sweden), and produces Isha times that are later than the calculated Fajr times! This is because the time between Maghrib adn Isha is not 90 minutes as assumed, but closer to 3 hours, resulting in Isha times past midnight and Fajr times before midnight.
A combination of 3 and 4 above was suggested by MWL 2003 one could use the night portion corresponding to the nearest loction where persistent twilight does not occur (defined as 48° latitude), calculate the corresponding local night portion, and add this to the local Maghrib time. A similar algorithm was implemented by ICOP 2009, where the estimate is based on the local average night portion under normal conditions.
The methods that can be practically applied at all locations up to the 65th laittude are the following:
Note regarding the length of the night:
In Hanafi fiqh, the night is defined as the time between sunset and sunrise.In Maliki and Shafi'i fiqh, however, night means the time between sunset and Fajr, which poses the problem of estimating Fajr in the first place, in order to obtain the length of the night. If, for simplicity, the time from Fajr to Shuruq is taken to be equal to the time from Maghrib to Isha, and n denotes the part of the night to be computed, then
1/n maghrib-shuruq =1/(n+1) maghrib-fajr
Some Islamic prayer time tables do not apply any of the above principles, instead they use other interpolation methods. For instance,
Criticism of some current prayer time tablesMany prayer time tables use some form of estimate (taqdir) for Fajr and Isha times in locations where these times to do not exist for a limited period during summer. However, in order to get a smooth transition to the prayer times in winter, the time table is "padded" in a way that it contains construed times for the entire period between the equinoxes. In other words. construed times are tabulated for dates when the prayer times exist according to their fiqh definition. Ramadan year 2008 and onwards is included in the period where fallacious times for Fajr are given.
regarding the construction of Fajr and Isha in summer
This problem was pointed out by the Cambridge Prayer Time Project 20044, but unfortunately does not seem to have received the attention it deserves. Below we will illustrate the problem for three specific cases.
Comparison between manipulated and real times for some common prayer timetables
In order to expose the problem, we have plotted
Construed Fajr times during Ramadan
We see that the curve of Rabita (IFS) fits 14.7° during winter time. For this angle, the period of persistent twilight lasts from May 5 to August 9, i.e. this is the period during which al-fajr al-sadiq cannot be observed. However the method of Rabita (IFS) does not return to the Fajr definition of 14.7° when the critical period is over. It continues to produce artificial values for 7 months of the year, from March 1 until September 30!
Ramadan year 1430 H. (2009) is from August 20 to Sept 19. For this month, the time difference between the Fajr time given by IFS´s and al-fajr al-sadiq range from 10 to 50 minutes in Stockholm. Further north, it is even more. If a person begins his fast at the Fajr-time given by IFS, it means that he is eating long after al-fajr al-sadiq, and his fast may not be valid.
Islamic Finder computes prayer time tables worldwide, that can easily be linked into any home page. Twilight angles can be set by the user, or one may use one of the preset schemes that are named "Egyptian Authority of Survey", "Islamic University of Karachi" etc. However, regardless of what settings are used, the program will invariably apply the interpolation algorithm called "angle based" (explained above). It cannot be switched off, and it is not limited to the period of persistent twilight. It continues to produce artificial values for Fajr until these latter coincide with the true values, i.e. from April 13 to August 29. It should be pointed out that this procedure is not sanctioned by Fatwa authorities in Egypt or Karachi, they are entirely a product of IslamicFinder's calculation scheme. In Ramadan 1430 H. (2009) the time difference between true Fajr and unduly construed Fajr times is up to 24 minutes.
These interpolation methods used by Rabita and IslamicFinder are not acceptable, and may lead to Muslims starting their fast too late.
Hizbul Ulama in Blackburn made a yearlong study observing for each day sunrise, sunset and morning and evening twilights. On the basis of these observations, the constructed a prayer time table for Blackburn. Rejecting categorically astronomical angles as a basis for prayer times calculation, they calculated the difference between Maghrib and Isha, and between Fajr and sunrise, observed in Blackburn, and added these to local sunrise/sunset times in other cities. In this way they constructed prayer time tables for various locations in the UK. - The third graph in the above figure compares the timetable for Blackburn with times computed with Birka for the angle 14.7°. We may first of all note that the coincidence is very good for the winter months - contrary to the statements of Hizbul Ulama, who state that no fix angle fits their data. - In summer time, when the true dawn does not take place, the Blackburn tables contain values for the time when light has spread all along the horizon, which corresponds in their case to an angle of 8.5°. Then the curve is "smoothed out" so as to avoid gaps. This last procedure spreads out the artificial values over the whole period from March to September. In other words, during these transition periods, interpolated values are given in the tables, even where al-fajr al-sadiq was actually observed!
1. It is not clear if SMHI is taking account of the sun passage over the horizon or not.
2. The principle of "Aqrab al-ayyam" was established for the Hanafi madhhab by Hazrat Thanvi in Imdadul Fatawa Vol 1, p 98 (quoted by Y. Miftahi, p. 111)
3. "With regard to the issue of First Light vs Tabayyun, Mufti Saeed Ahmed Palanpuri with the support of Mufti Mohammad Amin and Mufti Abdur-Rauf says that there is disagreement in Hanafi Fiqh on whether the beginning of Fast is from Fajare Haqiqi or from its Tabayyun (i.e. when the light has spread along the horizon). Whilst the beginning of the Fast at First Light is the safer of the two, the time of Tabayyun allows ease and is permissible. This ruling is supported by Mufti Saeed Ahmed who referred to Hazrat Molana Binori’s Marifuss Sunan, Volume 5, Page 323, which itself is based on Fatawa Hindiyah, the Fatawa Alamghiri, which uses Halwani, Al Muhiti and Khazanatul Fatawa in support of this ruling." (Y. Miftahi p. 84)
4. "The Cambridge Prayer timetable Project uses the “Daruri” shariah rules, which indicate that if anything is permitted under “extreme necessity” the permission should only be confined within that terminology and not beyond. And those exceptional cases should not be generalised. Accordingly, if we have to estimate some prayer times – when the Shariah phenomena is difficult to implement and interrupted or absent, we should only confine our estimation under these circumstances. Here in Britain, the shariah phenomenon (i.e., the absence of persistent twilight) is present for about for about eight months. We therefore need only to estimate, change or adjust any of the prayer times for the period when the shariah phenomenon is absent or difficult to implement. In some prayer time-tables the timings for prayers are changed all year round without any valid reason. We only need to estimate the prayer timings if the shariah phenomena is absent or difficult to implement. We follow and abide by the Islamic shariah’s rules in order to determine the prayer timings in the period where the shariah phenomena is stable, consistent and is implement able." (The Cambridge Prayer Timetable Project, 2004, p. 5 - emphasis of this author)
5. There is ikhtilaf in the Hanafi madhhab regarding the beginning of Isha. For a discussion of the subject see this link, or the summary given by (Dar al-Ifta al-Misriyya, Fatwa No. 20070). The red twilight is taken as the fatwa in some of the basic fiqh texts of the madhhab (Nur al-Idah/Maraqi al-Falah/Imdad al-Fattah, Mukhtasar al-Quduri/al-Lubab), while the white twilight is preferred in Radd al-Muhtar. There is agreement that the best thing is to avoid praying between the disappearance of the red and white twilights, in order to avoid going against any of the opinions.
6. Nuh Keller writes in the Appendix of "The Reliance of the Traveller", p. 895 (Section w19.2):
"For both the dawn prayer (subh) and the dawn that marks the beginning of fast-days of Ramadan, if there is sunset and sunrise at one's location but not true dawn because of the persistence of twilight all night, one copies the nearest city that has the true times in terms of the amount of time by which dawn in that cite precedes sunrise there. Thus if dawn in this nearest city precedes sunrise by 90 minutes, one's own "dawn" occurs 90 minutes before the sunrise in one's own city. And similarly for the amount of time by which nightfall ('isha) follows the sunset prayer (maghrbib)."