MESHWERET ISLAMIC CALENDAR

**Period of Tamkin (Detailed Part)**

The period from the moment when the center of the Sun sets at true horizon to the moment when its rear edge descends by the same amount of angular distance, that is, down to canonical horizon, and lights disappear from the highest hill is called the **(Tamkin)**. The difference of time between true time that is determined by calculation and the shar’î time for a certain prayer of namâz is termed the time of **(Tamkin)**. For the difference of time between the true and canonical times of a namâz is equal to the difference of time between the true horizon and the canonical horizon. And this difference, in its turn, is called the time of Tamkîn.

**There is one canonical horizon in every city.** The canonical times are found by subtracting one unit of Tamkin from the calculated true prayer times before midday, which is a period wherein the Sun traverses the canonical horizon before traversing the true horizon. Examples of this are the times of imsâk and sunrise. On the other hand, to find the canonical prayer times within the period after midday, wherein the Sun transits the canonical horizon after transiting the true horizon, one unit of Tamkin is added to the true times. Prayer times in this category are early and late afternoon, evening and night. The time of tamkîn for each prayer time is approximately the same. It is written in the annotation to the book **Imdâd** that the line of apparent horizon, not the true horizon, is to be taken into account in determining the times (of prayers).

There are three kinds of sunset: the first is the time when the true altitude of the Sun’s centre is zero, called the true sunset (**haqîqî ghurûb)**; the second is the time when it is seen that the apparent altitude of the Sun’s rear edge with respect to the apparent horizon of the observer’s location is zero, that is, when its upper edge disappears at the line of apparent horizon of the location, called the apparent sunset (**zâhirî ghurûb**); the third is the time when the altitude of the rear edge relative to the canonical horizon is calculated to be zero, called the canonical sunset (**shar’î ghurûb**). It is noted in all fiqh books that, of these three kinds of sunset, the sighting of the apparent sunset is to be taken as basis. However there are different lines of apparent horizons for different heights.**The sunset at the canonical horizon is the apparent sunset observed from the highest hill (of the location)**. At the time of the calculated true sunset, the Sun is seen to have not set yet at the lines of apparent horizons of high places. This shows that the time for evening prayer and for breaking fast begins not at the moments of the first and second types of sunset (as mentioned above) but at a time later than that. First, the true sunset and then the apparent sunset, and finally the canonical sunset take place. It is noted also in the book **Majma’al-anhur **and the Shafi’î book **Al-anwâr li-a’mâlil abrâr** that **the canonical sunset**, which is determined by calculation, is to be taken into account.

In places where the apparent sunset cannot be seen because of hills, high buildings and clouds, the time of sunset, as stated in a hadîth, is the time of darkening of the hilltops in the east. This hadîth sherîf shows that **“in the calculation of the time of sunset or sunrise, not the true or apparent altitudes but the canonical altitudes of the Sun relative to canonical horizon are to be used,”** that is, the Tamkin must be taken into account. This hadîth should be followed, i.e., the Tamkin should be taken into account in calculating the canonical times of all the other prayers, too, because the true riyâdî times are determined by (a single-step astronomical) calculation. There is a difference of a Tamkin between the true and canonical times of a prayer. **The Tamkin corresponding to the highest hill of a city cannot be changed**. If the Tamkin time is reduced, the late afternoon and the following prayers, being performed before their prescribed time, and, by the same token, the fasting being begun after the end of the sahur (imsâq), will not be sahîh (valid). Up until the year 1982 no one had even considered re-arranging the period of Tamkin in Turkey, and for centuries all the Scholars of Islam, Awliyâ’, Shaikh al-Islâms, Muftîs and all Muslims had performed all their prayers and started their fastings at their canonical times. (Meshweret Islamic Calendar gives the correct times of prayers and fasting without making any alterations in the period of Tamkin.)

**NOTE:** To determine the zuhr time in adhânî true time from the ghurûbî true zawâl time, the Islamic scholars subtracted the Tamkin at ghurûb from it, and they obtained the ghurûbî zawâl time again by adding the period of Tamkin, which is the method for finding the shar’î time at zawâl. This shows that the Tamkin at the time of zuhr must be equal to the difference of time between the true and canonical horizons, i.e., to the Tamkin at sunset. Likewise, tamkins for all the shar’î prayer times are equal to those at sunrise and sunset.

The period of temkin during the **zuhr** time is equal to the period of temkin during **imsak **(fajr) as well as it is equal to the period of temkin during **sunrise** and **sunset**. We have observed that, in the determination of true fajr and sunrise in adhânî time, twice the period of Tamkin was subtracted in the tables of canonical times for Erzurum by hadrat Ibrâhîm Haqqî and also in the book **Hey’et-e felekiyya** by Mustafa Hilmî efendi in 1307. The same is written in the book **Hidâyat-ul-mubtadî fî ma’rifat-il-awqât bi-rub’i-d-dâira** by ’Ali bin ’Uthmân; he passed away in 801 **[1398 A.D.]**. Hasan Shawqi Efendi of Hezargrad, senior professor of Islamic sciences at the Fâtih Madrasa and translator of Kadûsî's **Irtifâ'-i sems risâlesi**, (Booklet on the Sun's Altitude), describes the method of finding the time of imsâk in its ninth chapter, and adds: "The times of true imsâk we have obtained by calculation are without Tamkin. A Muslim who will fast must stop eating 15 minutes, i.e. two units of Tamkin, before this time. Thus, they will protect their fast from being fâsid." As is seen, to find the canonical adhânî time of imsâk, he subtracts twice the Tamkin from the true ghurûbî time and reports that otherwise the fasting will be nullified. [One unit of Tamkin is subtracted from the ghurûbî time to find the Shar’î time, and another unit of Tamkin is subtracted from the ghurûbî time to convert it to the adhânî time.]

**THE CALCULATION OF THE PERIOD OF TAMKIN**

Ahmed Ziyâ Bey states, “The value of the dip of horizon in angular seconds is equal to the product of 106.92 and the square root of the altitude in metres of the observer from the sensible horizon of the location.” Since the highest hill near the observer in Istanbul is Çamlica with a height of 267 metres, the greatest angle of dip of horizon is 29' (in Istanbul). In the table of daily Tamkin which Tâhir Effendi, the Head of Astronomers, calculated, –he prepared it when he assumed office as Director of Cairo Observatory in 1283 A.H. (1866)–; and in the book **Marâsid** by Ismâ’îl Gelenbevî the Virtuous; and in the Turkish book **Mi’yâr-ül-evqât **written by Ismâ’îl Fehîm bin Ibrâhîm Hakkî of Erzurum in the year 1193; and at the end of the calendar for solar year 1286 (lunar 1326) of the Hegira prepared by Sayyid Muhammad Ârif Bey, the Head of the Astronomers, it is written: “Since the greatest angle of dip of horizon is 29' for Istanbul, and, at this level which is below the true horizon, i.e., below zero, the refraction of light is 44.5', and since **the apparent radius **of the Sun is at least 15'45", these three altitudes result in the sighting of the Sun before it rises above the true horizon. As for the horizontal parallax, it results in a delay of the sighting of sunrise. Hence, one finds the angular altitude of the Sun to be 1° 29' 6.2" by subtracting 8.8" of **parallax** from the sum of these three altitudes. The period from the moment when the center of the Sun sets at true horizon to the moment when its rear edge descends by the same amount of angular distance, that is, down to canonical horizon, and lights disappear from the highest hill is called the **Tamkin**. With the help of the formula used for determining the prayer times [and a scientific calculator, e.g., Casio], the astronomical (fannî) and canonical times of sunset are calculated for any day in Istanbul by utilizing the Sun’s altitudes relative to the true horizon (0° 0' 0" and -1° 29' 6.2") at these two setting times, i.e., setting of the Sun’s center at the true horizon and setting of its upper edge at the cannonical horizon. The difference between the two is the **Tamkin.**” For instance, on March 21 and on September 23, the angular altitude is 1°29'6.2" and the Tamkin, i.e., the time taken by the edge of the Sun to descend that much altitude below the true horizon along its trajectory, is 7 minutes 52.29 seconds (for Istanbul). Since there are the variables of the declination of the Sun and the latitude of the location in the formula of prayer times, period of Tamkin in a certain city varies, depending on the degree of latitude and date. Although the period of Tamkin for a city is not the same for every day or hour, there is a mean period of Tamkin for each city. These Tamkin periods are given in Table of Tamkin Periods. As a precaution, 2 minutes is added to the Tamkin determined by calculation, and the mean Tamkin for Istanbul is accepted to be 10 minutes (of time). At any place with latitude less than 44°, the difference between maximum and minimum tamkins in a year is about one or two minutes. **A city has only one tamkîn, which is utilized to find the canonical time of a certain prayer of namâz from its true time.** There are not different tamkîns for different prayers of namâz. And there is no tamkîn in apparent times, either. If a person, believing that the period of Tamkin is something added with precautionary considerations, continues to eat for 3 to 4 minutes after the imsâq (time to start fasting), his fast becomes fâsid (null) as are his fast and evening prayer when he takes the sunset to be 3 to 4 minutes earlier, which is written in the book **Durr-i Yektâ**, too. The declination of the Sun, Tamkin and the Equation of Time change every moment at a location, and the unit of haqîqî ghurubî (real sunset) time is slightly different from the unit of true zawâl time, and therefore, the calculated prayer times are not precisely exact. To be sure of the beginning of a prayer time, 2 minutes of precaution is added to the period of Tamkin calculated.

It is seen in the calendar ’**Ilmiyye sâlnâmesi** prepared by **Mashîhat-i Islâmiyya**, the-highest council of the Ottoman ’ulamâ’, for the year 1334 [1916 A.D.] and in **Türkiye’ye Mahsûs Evkat-i Ser’iyye** book no. 14 published by the Kandilli Observatory of the University of Istanbul in 1958 that Tamkin was taken into account in the calculations of the canonical times of prayers. We have seen that the times determined as a result of the observations and calculations carried on by our staff, composed of true men of Islam and specialized astronomers using latest instruments, are the same as those found and reported by Islamic scholars, who used the **rub-i-daira **= astrolabe, for centuries.

Therefore, it is not religiously permissible to change **Tamkin Period**, consequently to change prayer times. By taking only the dictionary meaining - not as a religious term - of the word "tamkin" into consideration which has to be used necessarily, without fail, in the computation of prayer times, to perceive it as a precautionary period is not true, and to condition the public opinion in this way is not right. Under the pretext of reducing the unnecessary and excessive Tamkin Period, to eliminate the unavoidable Tamkin Period, partly or completely, means to change the times of imsaqs and prayer times, that is to spoil the fasts and salats of the muslims.

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