Calculation with the help of sightings or based solely on sightings?

Whether calculations or exclusively sightings determine a valid prayer time is a question which falls within the remit of Islamic scholars and cannot be answered here. What we can answer here are some questions regarding the advantages and disadvantages of the two opinions.

Let us start with determination based exclusively on sightings. Initially, it sounds very simple, as one only needs to find a location where the horizon can be observed. From this location, Fajr, for example, must be observed and the current prayer time communicated. This would then have to be carried out in this way for every village and every town or city where Muslims live. However, since this method is subject to a strong influence from light pollution, the prayer times deviate significantly from one location to another. Thus, a settlement located next to a brightly lit industrial estate would pray about 30 minutes later than a settlement 3 km away that does not have as much artificial light on the horizon. The prayer time would also commence temporarily or somewhat prematurely if there were a power cut. Thus, humans would be able to manipulate the prayer times with their artificial light. Whoever follows this opinion would, however, also have to agree to this. Cases in which prayer timetables have been created based on sightings remain unknown in Germany to this day. The proper creation of such a timetable would need to be preceded by long-term observations documenting the times weekly, and possibly several times a week.

The other opinion is that we calculate the prayer time using values that have been determined through observations. Muslims have been able to calculate the prayer time based on the sun's angle for about 1,000 years. For instance, Ibn Shatir, the chief Mawaqit of the Umayyad Mosque in Damascus in the year 777 AH, said: “As for the time of the dawn prayer, it is at daybreak, and if one knows this, one must place the nadir on the eighteenth arc from the direction of the Maghrib”. Western sources such as the New American Practical Navigator of 1802 also report on the angle of twilight: “By the preceding method, you can determine the beginning or end of twilight by calculating the hour when the sun's zenith distance is 108 degrees (or when the sun is 18 degrees below the horizon); for it has been found by observation that twilight begins or ends when the sun is at this distance from the zenith.” This was long before science categorised the phases of twilight. The statements of Islamic astronomers and scholars from history, as well as from science, are numerous and can be researched by anyone themselves. The fact that Muslims today no longer agree on what the correct angle is can be attributed to several reasons. On the one hand, most countries today are too bright to still detect the initially very faint twilight, which includes the problem that sightings are carried out in locations and by individuals that are not qualified for it. On the other hand, based on interpretations of certain astronomical texts, statements are made without ever having actually carried out a sighting. And there are also people who say that for the angle, we only follow sightings, without taking artificial light into account. With them, the same problems arise that have already been mentioned in the previous paragraph. Thus, there can be no degree value that would be valid for all locations, and one would have to determine a different degree value for every village and every city through observation, whereby one would ultimately belong to the other opinion again. According to this opinion, one would no longer be allowed to say the angle of Fajr is such and such, but merely: in our location, the angle is such and such. If we therefore hold the opinion that we take artificial light into consideration and use the first light that becomes visible when no other electrical light is present as the basis for the beginning of twilight, then one must return to the values of the old astronomers and science. Because there was no one who said that the first light of twilight is present at an angle lower than 18 degrees. Whoever claims this must belong to the other opinion and may, under certain circumstances, not advocate any degree values at all. Thus, it can be said that the correct degree value for Fajr is 18, and Fajr can be seen in areas without electrical light at approximately this degree. Therefore, Fajr can be calculated for any location in the world with this angle, and this is the opinion of the majority of scholars and astronomers in Islamic history.