Welcome to the Moon Visibility Explorer
مرحباً بكم في مستكشف رؤية القمر — أداتكم الشاملة للتنبؤ برؤية الهلال وحساب التقويم الهجري
The Moon Visibility Explorer is an advanced astronomical tool designed for individuals, communities, and researchers who need accurate predictions for lunar crescent visibility. By utilizing the well-regarded scientifically-validated Odeh V-criterion, our calculator provides high-resolution data on moon sightings and generates reliable Hijri calendars for over 70 major cities globally. Whether you need to determine the start of Ramadan, plan for Eid al-Fitr, or calculate Hajj dates, this tool delivers the scientific data you need.
How to Use This Calculator
To get started, simply utilize the control panel above to select a Reference Date. The interactive global map will immediately calculate the phase of the moon and categorize global visibility into distinct zones:
- Easily Visible (Green) — مرئي بسهولة: The crescent can be seen with the naked eye even in less-than-ideal conditions.
- Visible with Perfect Conditions (Yellow) — مرئي في ظروف مثالية: Sightings rely on a clear sky and unobstructed horizon.
- Optical Aid Needed (Orange) — مرئي بمساعدة بصرية: Telescopes or binoculars are required to locate the new moon.
- Not Visible (Red) — غير مرئي: Sighting is impossible under any conditions.
You can also generate an entire 12-month Lunar Calendar for your selected city. Click the "Calculate Lunar Calendar" button to predict the start of each month over an entire year layout, taking into account complex shared night calculations. The generated calendar can be exported as a PDF, downloaded as CSV data, or imported directly into Google Calendar.
Understanding the Odeh V-Criterion
Developed by Palestinian-Jordanian astronomer Mohammad Shawkat Odeh in 2004, the V-criterion is an empirical model based on 737 verified crescent observation records collected worldwide. Unlike purely geometric calculations, the Odeh model evaluates the topocentric crescent width (how thick the illuminated portion of the moon appears) and the arc of vision (how high the moon is above the sun at sunset). This sophisticated mathematical approach ensures that our tool accounts for real-world optical limits, providing one of the most reliable predictors for the Islamic Hijri calendar available today.
The Odeh criterion has been adopted by the Islamic Crescents' Observation Project (ICOP) and is used as a reference by numerous national moon sighting committees. For a detailed examination of the mathematical formula and comparison with other criteria (Yallop, SAAO, Maunder), visit our Methodology page.
Popular Cities for Moon Sighting
Moon Visibility Explorer supports over 70 major cities worldwide. Here are some of the most popular locations used by our community:
Why Choose Moon Visibility Explorer?
Unlike many Islamic calendar tools that rely on simplified tabular calculations or pre-computed tables, Moon Visibility Explorer performs real-time astronomical computations for every query. Our tool calculates the precise positions of the Sun and Moon using professional-grade ephemeris algorithms (VSOP87 for solar position, ELP2000 for lunar position), then applies the Odeh V-criterion to determine visibility at over 16,200 grid points across the globe. This means our predictions are not approximations — they are based on the same mathematical models used by professional observatories.
All calculations run entirely in your browser using Web Workers, ensuring both fast performance and complete privacy — no personal data is ever sent to a server. The tool is free, requires no account, and works on any modern device.
على عكس أدوات التقويم الإسلامي الأخرى التي تعتمد على حسابات مبسطة أو جداول محسوبة مسبقاً، يقوم مستكشف رؤية القمر بإجراء حسابات فلكية في الوقت الفعلي لكل استعلام. جميع الحسابات تتم في متصفحك محلياً مما يضمن الخصوصية الكاملة.
Learn More About Islamic Astronomy
Explore our library of educational articles about the Islamic calendar, moon sighting, and lunar astronomy:
- When Does Ramadan Start? — Predictions and planning guide
- Eid al-Fitr & Eid al-Adha Dates — When to expect the two Eids
- History of the Hijri Calendar — From pre-Islamic origins to modern systems
- How Moon Sighting Committees Work — Country-by-country guide
- Islamic vs. Gregorian Calendar — Key differences explained
- Understanding Lunar Phases — The astronomy behind the crescent
- Moon Sighting Tips — Practical guide for observers
- Shared Night Explained — The fiqh concept and how we implement it
Also visit our User Guide for step-by-step instructions, check the FAQ for common questions, or explore the About page to learn about our mission.