The Islamic Centre of Aachen (ICA) and its members were substantially involved in finding a theological solution for the calculation of prayer times at latitudes higher than ±45° in the past. ICA’s commissioned team and its leader Prof. Dr. Mohammad Hawari have implemented this solution using the usual algorithm for the calculation of prayer times. This implementation was then used to provide prayer times for many congregations in Europe. Since then, ICA is rendering this service as an institution and in doing so is pursuing nothing but Allah’s (s.w.t.) benevolence.
At the same time, ICA and its administration knew, that this method for the calculation of prayer times, which was developed in the 1980’s, needed to be refined and improved. Due to this, the computer-program for the calculation of prayer times was ported to a modern platform already in the late 80’s. Beyond that however, there were no further attempts to improve the calculation of prayer times. One major reason for this was the decease of Prof. Dr. Hawari, who was carrying the main responsibility for ICA’s prayer times at that time. His loss was accompanied with the loss of expertise regarding this field: neither the source code of the computer-program nor the calculation’s algorithm was available for ICA. Moreover, ICA was still considered as a competence center and thus was forced to build and gather new capacities and competences.
Therefore, ICA started the prayer times work group (PTWG), which was supposed to revitalize the development and improvement of the calculation method. At the same time, important organizations like the European Council for Fatwa and Research (ECFR) added this topic to their agendas.
For the purpose of taking the next important steps regarding the development of a new, improved calculation method, ECFR organized a symposium in March 2016 with the topic “Calculation of Prayer Times in Germany and the Possibility for a Unification” in Berlin. Represented by the PTWG and its leader Abdullah Jaber, ICA participated in this symposium as an invited guest pro-actively and was the host of a second conference about this topic in February 2018.
The PTWG reviewed the state and defined the tasks, duties and goals in a first step. Within these insights they consulted Mr. Harun Acaroglu. Mr. Acaroglu had already checked and successfully reproduced ICA’s prayer times beforehand within an independent general analysis of his own, where he checked and examined different prayer time tables. Based on his insights about ICA’s prayer times calculation, the PTWG and Mr. Acaroglu concluded, that the following aspects are mandatory for a precise calculation of prayer times:
- The Sun’s Parallax:
The solar altitudes that are calculated with the usual algorithm are referring to an observer, who is assumed to be in the Earth’s center. This approximation results in a slightly higher solar altitude, i.e. an observer on the Earth’s surface would measure a slightly smaller solar altitude than calculated. This discrepancy, which is given by the solar parallax with respect to the Earth’s center and its surface, has to be treated correctly.
- Extent of Solar Disk:
The usual algorithm calculates the time, at which the Sun’s center reaches a certain altitude above the horizon. But for prayer times, it generally is decisive to know the time, at which the solar disk’s upper edge reaches a certain altitude.
- Topology of Cities:
According to the usual algorithm, solar altitudes are calculated for one certain point on the map, hence for one tuple of latitude and longitude. In fact, it is necessary to calculate prayer times for cities, i.e. areas on the map.
Furthermore, a city in general has different altitudes. For an observer on a higher level, the Sun’s altitude above the horizon is higher, which also needs to be taken correctly into account.
- Atmospheric Refraction:
Sun rays which reach an observer on the Earth’s surface, have to pass its atmosphere at first. Here, these rays are refracted towards the Earth’s surface. This effect is called atmospheric refraction. Especially when the solar altitude is close to zero, i.e. at sunset and sunrise, this effect is not negligible and therefore crucially matters for the determination of the evening prayer time and sunrise.
- Variation of Relevant Quantities:
The calculation of solar altitudes involves quantities, like the solar declination or the equation of time, which vary throughout one day. Depending on the calculated prayer time and the season of year, it is necessary to decide which of the values that these quantities accept throughout one day should be used.
In the traditional Islamic literature about prayer time calculations, the above mentioned corrections of solar altitudes are called “Tamkeen-Calculation”. The necessity to include the tamkeen-calculation was then checked and confirmed theoretically as well as practically within the scope of several sighting expeditions. Thus, ICA decided to use an algorithm developed by Mr. Acaroglu, which includes an automated calculation of tamkeen, as the base for a new prayer time calculation method. Additionally it was decided, that a solar altitude of -17° for the night prayer (al-Isha’) and a solar altitude of -18° for the morning prayer (al-Fajr) will be used further on.
Beside these aspects, which only refer to the calculation algorithm itself, the PTWG was also advised, that Prof. Dr. Hawari’s algorithm uses the so called “Aqrabu’l-Bilad bi’n-Nisbah” method for latitudes above ±45° for the determination of the morning prayer and night prayer times throughout the whole year. This method calculates the night length’s ratio to the timespan between the evening and the night prayer as well as its ratio to the timespan between the morning prayer and sunrise at a latitude of 45°. Then, it applies these ratios to places which are at a higher latitude.
Since the astronomical signs for the morning and night prayers are only missing for a certain (latitude depending) number of days within the year, the PTWG has come to the conclusion that using the Aqrabu’l-Bilad method for days on which the mentioned signs exist is not permitted.
One goal of the above mentioned conferences was also to find a better solution for this problem in Islamic jurisprudence (al-Fiqh). Especially on days, where the astronomical signs exist, the prayer times should also be calculated according to them. Within the scope of his work in the PTWG, Mr. Salim Albogha has developed a solution for this problem, which he presented at the conference in February 2018 and which is going to be discussed at a future conference. According to this solution, the prayer times of the morning and night prayer are calculated as follows:
The astronomical night is defined as the time throughout which the solar disk is below the horizon. During this time the Sun descends to its minimum altitude and then starts ascending. If, for example, the minimum altitude is -30°, then during night the Sun will first descend from 0° to -30° and then ascend from -30° back to 0°. Thus, the Sun is covering a total vertical distance of 60° throughout the astronomical night.
On days, on which one third of this distance is greater than 17° or 18°, the prayer times for the morning and night prayer are determined according to the astronomical signs, i.e. when the Sun reaches -17° and -18° respectively. On days, on which this distance is less than 17° and 18° respectively, the prayer times of the morning and night prayer will not be determined according to the astronomical signs. On these days, the night prayer begins when the Sun has traveled one third of the total vertical distance that is covered throughout the astronomical night. The morning prayer begins, when the Sun has traveled two third of this distance.
If, for example, the minimum solar altitude is as mentioned above -30°, then the Sun will travel a vertical distance of 60° at night. One third of this distance is 20°. On such a day the times for the morning and night prayer are calculated according to the astronomical signs, thus at -17° and -18° respectively. But if we take a day, where the minimal solar altitude is -24°, then the vertical distance travelled by the Sun throughout the astronomical night will be 48°. One third of this is 16°. On such a day the night prayer begins, when the Sun descends to an altitude of -16°. The morning prayer, in turn, begins, when the Sun ascends to an altitude of -16°.
This method is called “Astronomical Third of the Night” and was affirmed through a theological assessment (al-Fatwa) by the scholar Dr. Ali Karadaghi.
In sum, the following changes were applied to ICA’s prayer times calculation method:
- A new algorithm that includes a tamkeen-calculation is used.
- On days, on which the signs exist, the prayer times for the morning and night prayer are calculated according to the astronomical signs (morning prayer: -18°, night prayer: -17°).
- On days, on which the astronomical signs exist very early/late or not at all, the times for the morning and night prayer are determined according to the astronomical third of the night method.