The Universal Asr Time Calculator & Shadow Ratio Horology Studio is an advanced in-browser astronomical prayer companion that calculates precise Salat al-Asr start times according to both classical juristic traditions: the Jumhur/Majority opinion (Shafi’i, Maliki, Hanbali) where shadow length equals the object’s height plus midday shadow (T = 1), and the traditional Hanafi juristic school where shadow length equals twice the object’s height plus midday shadow (T = 2).
Powered by pure client-side spherical trigonometry and solar ephemeris algorithms, the tool computes real-time Solar Noon (Zawal), solar declination, and the unavoidable midday baseline shadow (S₀ = tan|φ – δ|) without sending any GPS coordinates or personal data to an external server. It features an interactive 2D Gnomon Shadow Canvas that visually animates afternoon solar rays, a ticking real-time countdown timer to the next adhan, full-day prayer horizon tables, monthly 30-day horology forecasts, 1-click .ics calendar export with 15-minute adhan alarms, and a 1200×630 high-resolution calligraphic prayer card generator for effortless social sharing.
Universal Asr Time Calculator & Shadow Studio
Precision astronomical prayer horology studio computing exact Shafi'i (1x) and Hanafi (2x) Asr onsets, virtual gnomon shadow trigonometry, live ticking adhan HUD, and calendar sync.
Calculated on onset
Calculated on onset
| Prayer / Milestone | Arabic | Exact Time | Astronomical Condition |
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* Times derived from spherical solar ephemeris with standard civil refraction (-0.8333° for sunrise/sunset, 18° Fajr angle).
| Date | Solar Noon | Shafi'i (1x) | Hanafi (2x) | Sunset (Maghrib) | Noon Shadow Ratio |
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Fiqh of Asr, Hadith of Jibril & Solar Shadow Mathematics
Narrated in Sahih al-Tirmidhi (149), Sunan Abi Dawud (393), and authenticated across classical collections: The Archangel Jibril descended to demonstrate the prayers to Prophet Muhammad ﷺ. On the first day, he led Asr when the shadow of an object equaled its height (T = 1). On the second day, he led Asr when the shadow of an object became twice its height (T = 2). He then announced: "O Muhammad, this is the time of the Prophets before you, and the time is between these two limits."
• The Jumhur (Majority) Position (Imam Malik, Imam al-Shafi'i, Imam Ahmad ibn Hanbal): Asr begins immediately when the shadow of an object equals its midday shadow (S₀) plus one times the object's height (S = S₀ + 1G). They cite Day 1 of Jibril's Imamat and the authentic hadith: "The time of Dhuhr continues until Asr arrives, which is when the shadow of a man is equal to his length" (Sahih Muslim 612).
• The Traditional Hanafi Position (Zahir al-Riwayah of Imam Abu Hanifah): Asr begins when the shadow reaches twice the length plus midday baseline (S = S₀ + 2G). This position ensures absolute certainty (*Yaqeen*) that the Dhuhr window has completely closed without any doubt. Notably, the two chief disciples of Abu Hanifah (Imam Abu Yusuf and Imam Muhammad al-Shaybani) agreed with the Jumhur 1x position.
At exact Solar Noon (Zawal / زوال), the sun reaches its highest meridian altitude. Unless an observer is in the tropics on the exact day of the solar zenith (where the sun is directly 90° overhead), a vertical gnomon casts a non-zero shadow northward or southward.
Islamic jurists established that this minimum noon shadow—known mathematically as S₀ = tan|φ - δ|—belongs to the midday zenith and cannot count toward the object's body shadow. Therefore, the shadow length threshold for Asr must always be calculated as:
The preferred time (*Waqt al-Ikhtiyar*) for Asr extends until the sun starts turning pale yellow before sunset. Delaying Asr until the sun is setting without a valid excuse is strictly disliked (*Makruh Tahrimi*):
«تِلْكَ صَلَاةُ المُنَافِقِ، يَجْلِسُ يَرْقُبُ الشَّمْسَ حَتَّى إِذَا كَانَتْ بَيْنَ قَرْنَيِ الشَّيْطَانِ، قَامَ فَنَقَرَهَا أَرْبَعًا، لَا يَذْكُرُ اللَّهَ فِيهَا إِلَّا قَلِيلًا»
"That is the prayer of the hypocrite: he sits watching the sun until it is between the horns of Satan, then he stands and pecks four rak'ahs, remembering Allah only a little" (Sahih Muslim 622).