Article 6 · Calendar studies

Which calendar gets it right? Germany’s prayer-time calendars compared

Whoever looks up prayer times in Germany gets different answers depending on the mosque association — usually minutes apart, in summer up to hours. Chapter 7 of Acaroğlu’s dissertation subjects the established calendars to the first systematic astronomical and juristic review: Diyanet/DITIB, Hicret (IGMG), Fazilet, Semerkand, Türkiye Takvimi and the IZA calendar. Some findings are sobering — including for our own house.

Two touchstones

The benchmark is a high-precision reference computation with full tamkīn (→ article 5) and the rulings of the four Sunnī schools of law. This yields two touchstones: first — does the calendar render the actual phenomena correctly, i.e. correct twilight angles and careful tamkīn corrections? Second — does it use artificial substitute times (taqdīr) only where the phenomenon actually ceases to occur? For by the consensus of all four schools, substitution is permissible only in the absence of the sign, not alongside a sign that actually exists (→ article 4).

The test case is Berlin in 2023: for every day and every prayer time, the difference between the published time and the reference computation was determined — more than 2,000 data points per calendar.

The calendars at a glance

Forty years of Diyanet: a chequered history

Until 1980 the Diyanet followed the Ottoman legacy: 19°/17°, subdivision of fajr into imsāk and ṣubḥ, location-specific tamkīn. Then things started moving: in 1981 — after the Brussels conference — ʿishāʾ above 45° N was replaced year-round by maghrib + 80 minutes, even on days when twilight actually ends. In 1983 the fajr angle was changed globally from 19° to 18° — a decision publicly justified only 30 years later, and one that even contradicted the resolution of the Diyanet’s own High Council for Religious Affairs (16°). Tamkīn was abolished and only partially reinstated later as flat 3- and 5-minute buffers — almost all of it without public announcement.

Particularly revealing: in 2012 the Diyanet commissioned an observational study of its own. Its result — dawn at a mean of −17.8° ± 1.2° — statistically supports a lower limit of −20.9° (99 % confidence); the Diyanet’s own 18° value is compatible with the data at a mere 13 %. Nevertheless, a 2013 press release presented the study as evidence for 18° — “in line with the principle of facilitation”.

The legal point weighs heavier: artificial times despite actually existing phenomena contradict the consensus of all four schools. Legal maxims such as “hardship begets facilitation” are secondary instruments — they cannot override the explicit text (Q 4:103). In Berlin, from 1983 to 2022, the artificial ʿishāʾ was always at least 25 minutes before the actual disappearance of evening redness, and the artificial imsāk (March–September) always at least 38 minutes after true dawn.

Hicret: fixed minutes instead of astronomy

The IGMG’s Hicret calendar has never computed imsāk and ʿishāʾ from solar altitudes but always from fixed spans: at first shurūq − 135 and maghrib + 90 minutes, over the years 121, 110, finally 80 and 70 minutes — identical for all places, although twilight duration increases strongly with latitude. The “64 minutes at the equator” cited as justification in 2016 is wrong even there; in Berlin the duration never drops below 83 minutes even under their own 12.5° premise.

The observation video published from Zandvoort in 2016 does not withstand scrutiny either: filmed in one of Europe’s most light-polluted regions (up to 184 times the natural sky brightness), fast-forwarded to minute 75 instead of 70 — and even in the final frame the evening redness is still clearly visible. The change was advised, among others, by Abdulaziz Bayındır, who places fajr at 9° — far outside any observation-based range.

The unified calendar (2023)

In 2021 the Diyanet and the ECFR convened an international prayer-times conference in Istanbul; since 2023 DITIB and IGMG use a joint calendar (18°/16°). The final declaration permits artificial times only in cases of exceptional hardship — yet the calendar itself switches to artificial times as early as mid-April, sooner than its own thresholds would allow. The artificial times match the declared principle (thirds of the legal night) on exactly two days a year; on all others the calendar follows an interpolation scheme so convoluted that the publishers describe it incorrectly in their own publications.

The main goal was missed as well: 17° had initially been resolved for ʿishāʾ, then internally lowered to 16° — without published observational results. As the IZA rejected the 16°, in the end only DITIB and IGMG merged — whose times had differed by barely ten minutes anyway.

Fazilet: the most constant — and the most precise

Since its first edition in 1973 the Fazilet calendar has computed with an unchanged 19°/17°, building on the Ottoman astronomers Ahmed Muhtar Paşa and Ahmed Ziya Akbulut as well as modern observation series. It subdivides fajr into imsāk (19°) and ṣubḥ (+ 20 minutes, after Babanzâde’s measure of 50 Qurʾānic verses), computes tamkīn in full — and uses artificial times only where the phenomenon genuinely ceases: during persistent whiteness the lower meridian passage (astronomical midnight) serves as imsāk, the actual ʿishāʾ is kept as long as it exists; only during persistent redness does aqrab al-bilād apply. In the Berlin comparison it typically deviates from the reference by only one to two minutes.

Among the calendars in consideration, only the Fazilet Calendar both strictly abides by the rulings of the four Sunnī schools and calculates prayer times with sufficient precision.

H. R. Acaroğlu, dissertation (2025), ch. 7.3

Semerkand and Türkiye: the problem of frozen times

Both compute with 19°/17° — Türkiye Takvimi with full (if coarse) tamkīn and transparent documentation, Semerkand without corrections for imsāk and ʿishāʾ. In summer both freeze the times of the last regular day for the entire period (“aqrab al-layālī”). That is doubly problematic: no distinction is made between persistent whiteness and persistent redness — so an artificial ʿishāʾ is used while the actual phenomenon still exists — and the frozen ʿishāʾ moves close to civil midnight: unnecessary hardship without real facilitation for imsāk.

The method is attributed to Ibn ʿĀbidīn — yet his Radd al-muḥtār contains nothing of the kind; on the contrary, Ibn ʿĀbidīn places fajr at astronomical midnight during persistent twilight. Not a single Islamic astronomer mentions “aqrab al-layālī”; Ahmed Tahir Efendi rather states explicitly that with the lower meridian passage the time of fajr and ṣubḥ has arrived.

And the IZA calendar? An honest stocktaking

The dissertation does not spare its own house. The old IZA calendar claimed 18°/17° — recomputation shows, however, that the actual angles were used only below 45° N: above that, artificial times by aqrab al-bilād with reference latitude 45° applied year-round, and tamkīn went entirely unconsidered for some 40 years — maghrib, for instance, was published too early on 289 days of the year.

In 2023 the IZA was one of the driving forces behind unification, yet rejected the 16° and introduced its own 17° variant of the new taqdīr method — whose implementation the dissertation demonstrates to be a flawed, unsuccessful reconstruction; the flat buffers (3 and 5 minutes) are even tighter than the Diyanet’s already insufficient ones. The author’s verdict is blunt: a lack of rigour that also shows the collaboration within the conference framework to have been suboptimal.

These findings are precisely why the IZA’s prayer-times working group rebuilt the computation from the ground up: actual angles as long as the phenomenon exists, and upon its genuine absence the continuous night-thirds algorithm of the fatwa (→ article 2) — implemented and verifiable in this app. Scholarship also means working through one’s own history honestly.

What do we take away?

Three lessons. First, constancy and transparency are themselves marks of quality — the Fazilet calendar, unchanged since 1973, performs best; the repeatedly revised Diyanet practice worst. Second, what matters is not the brand but the method: observation-based angles (19°/17°), full tamkīn, artificial times only upon the genuine absence of the phenomenon. Third, no legal maxim substitutes for observation: where your own study measures −17.8°, an 18° value cannot be justified by “facilitation”.

This text is a factual introduction, not a fatwa. Your local scholars and community remain authoritative.

More from the knowledge section

The polar problem — where local sighting reaches its limit · Thuluth al-layl — the third-of-the-night method and its justification · Where do 18° and 17° come from? — Twelve centuries of the angle debate · Are the prayers even obligatory then? — The schools’ dispute · Why tamkīn? — A thousand years of precision corrections