The Universal Dhuhr Time Calculator & Solar Meridian Transit Studio is an advanced, privacy-first astronomical web application designed to compute true solar noon, determine the exact moment of Zawal (زوال الشمس), and monitor the prohibited midday prayer window (Waqt al-Karahah / الاستواء) with mathematical precision.
Engineered according to both celestial orbital mechanics and the consensus of the four major Sunni schools of Islamic jurisprudence (Hanafi, Maliki, Shafi’i, and Hanbali), this tool calculates the real-time Equation of Time (EoT), solar declination ($\delta$), and gnomon minimum shadow ratio ($S_0$) to establish an authentic Dhuhr prayer entry window with customizable precautionary safety buffers (+1 to +5 minutes).
Featuring a real-time live ticking countdown HUD, an interactive 2D solar dome canvas simulator, a complete full-day prayer horizon matrix, a 30-day forward monthly transit calendar, 1-click recurring iCalendar (.ics) synchronization with built-in 15-minute advance warnings, and a 1200×630 shareable calligraphic social card generator, this tool provides worshippers, scholars, and mosque committees with an authoritative horology companion. Built exclusively for 100% in-browser client-side execution with zero external libraries and zero coordinate transmission to external servers.
Universal Dhuhr Time Calculator & Solar Transit Studio
High-precision astronomical solar noon & Zawal engine. Compute the true celestial zenith, monitor the prohibited midday prayer window (Waqt al-Karahah), visualize real-time celestial sun arcs, and synchronize verified prayer horizons.
| Horizon Phase | Islamic Nomenclature | Calculated Time | Fiqh Significance |
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| Date | EoT (Shift) | True Solar Noon | Dhuhr Adhan | Forbidden Window |
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📖 Fiqh of Dhuhr, Zawal Science & Forbidden Prayer Horology
In Islamic jurisprudence (Fiqh), the canonical time for the obligatory Dhuhr prayer does NOT begin at the exact moment of astronomical solar midday when the sun is at its highest celestial peak (Istiwa' / نصف النهار). Rather, all four Sunni legal schools (Hanafi, Maliki, Shafi'i, and Hanbali) hold consensus that Dhuhr begins strictly at Zawal (زوال الشمس) — the precise instant the sun departs from the celestial meridian and begins its descent toward the west.
— Sahih Muslim (Hadith 612)
The interval when the sun is stationed precisely at its midday zenith (حين يقوم قائم الظهيرة حتى تزول الشمس) is one of the three explicitly prohibited prayer windows (أوقات النهي) in the Sunnah. Performing voluntary Nafl or Sunnah prayers during this window is strictly prohibited (Makruh Tahrimi).
— Sahih Muslim (Hadith 831)
Astronomically, the sun's visual disk measures approximately 0.53° in angular diameter. It takes around 2 minutes for the entire body of the sun to cross the celestial meridian line. Islamic jurists therefore mandate adding a +2 to +5 minute precautionary safety buffer (احتياط) after astronomical noon before announcing the Dhuhr Adhan, ensuring that the prohibited window has decisively concluded.
Many people assume that solar noon always happens at 12:00 PM standard clock time. However, due to two astronomical factors — the Earth's 23.44° axial obliquity and its eccentric elliptical orbit around the sun — apparent solar days vary throughout the year.
This discrepancy is quantified by the Equation of Time (EoT). Throughout the calendar year, True Solar Noon can oscillate by as much as -14 minutes in early February to +16 minutes in early November relative to mean solar time. Our built-in ephemeris algorithm calculates the exact solar transit coordinates in real time for any observer on Earth.
On Fridays (Yawm al-Jumu'ah), the jurists discuss the prohibited window prior to Zawal. According to the Shafi'i and Hanbali schools, voluntary prayers in the mosque on Friday are exempted from the prohibition while waiting for the Imam. The Friday Jumu'ah prayer and Khutbah time arrives with the entry of Dhuhr (at Zawal), replacing the four Rak'ahs of regular Dhuhr with two Rak'ahs preceded by the sermon.