moonsighting.com
What Moonsighting.com is and why people use it
Moonsighting.com is a long-running informational site focused on the Islamic lunar calendar and the practical question that shows up every year: when does a new Hijri month begin, especially Ramadan and Shawwal (Eid al-Fitr). The site’s core promise is pretty straightforward: it collects moon sighting reports from around the world and publishes them, while also providing prediction tools like crescent visibility maps and “visibility curves” to help communities understand where the new crescent (hilal) is likely to be seen.
For many mosques, local hilal committees, and ordinary families, the tension is familiar. Some follow local physical sighting only. Some follow sightings from a broader region. Others use astronomical calculations as the primary method. Moonsighting.com sits in the middle of that reality by trying to document what was reported (observational data) and also show what was expected (astronomical prediction).
The Moonsighting Committee Worldwide and how reports are gathered
A major part of the site is tied to the Moonsighting Committee Worldwide (MCW). MCW is presented as a network of members in different locations who report whether the crescent was seen, and under what conditions. The site invites people to join and submit reports, and it publishes those reports around the start of each lunar month—when the crescent is relevant.
That “reporting network” idea matters because crescent visibility is extremely sensitive to local conditions: sky clarity, humidity, haze, observer experience, optics used, and where you are on Earth. Even when the geometry is “favorable,” weather can wipe out visibility. And in marginal cases, people can claim sightings that later appear inconsistent with basic astronomical constraints. MCW’s structure is basically a way to gather many local observations into a single stream, month after month.
Crescent visibility maps and what they’re actually showing
One of the site’s most-used resources is its crescent visibility maps covering many Hijri years. These maps are meant to show regions where the new crescent should be visible (and with what kind of aid), based on calculation. Moonsighting.com presents these maps as a planning and decision-support tool, not just as a pretty graphic.
Under the hood, most modern visibility mapping approaches are tied to astronomical criteria that relate to things like the moon’s elongation from the sun, the moon’s altitude at sunset, the age of the moon since conjunction, and the expected brightness/width of the crescent. Different researchers and institutions propose different thresholds and classifications, but the general shape of the problem is the same: you’re modeling whether the thin crescent has enough contrast above the horizon glow to be detectable.
A common reference in this space is the Yallop method, which is used in some official and semi-official map products and computes a visibility parameter from lunar-solar geometry and crescent width. That’s not the only method in existence, but it’s a well-known one in the broader ecosystem of crescent prediction.
Ramadan and Eid pages: where prediction meets community decision-making
Moonsighting.com also publishes guidance pages specifically for Ramadan and Eid al-Fitr, including dates tied to astronomical new moon (conjunction) times and visibility-based reasoning for when Ramadan or Shawwal would begin in different contexts (often framed with reference to North America in some of its statements). These pages are popular because people want a practical bottom line early—travel planning, school/work scheduling, mosque logistics, and so on.
It’s important to be clear about what this kind of page can and can’t do. Astronomical conjunction is not the same thing as crescent visibility. Conjunction is a precise moment, but visibility is messy and depends on location and conditions. So when a site states an expected first day, it is effectively adopting a rule set (for example, a visibility threshold and a geographic scope) and then projecting an outcome. That outcome may match what some communities follow and differ from others.
How Moonsighting.com fits into the wider “moonsighting vs calculation” debate
The Islamic legal and communal debate isn’t just technical; it’s also about authority and unity. Some communities prioritize local sighting as an act of worship and testimony. Others prioritize calculation to avoid last-minute uncertainty, especially in places where sighting is difficult or where communities are geographically dispersed. Moonsighting.com is often used by people on both sides, but for different reasons: sighting-focused groups may use it to compare reports and plausibility, while calculation-inclined groups may use its maps and predicted outlook as a justification for early planning.
In practice, many organizations adopt hybrid approaches: calculations to rule out impossibilities, then reliance on verified sightings when feasible. This is also why having a repository of reports matters—if a claimed sighting happens where the moon set before the sun, or where visibility criteria strongly suggest impossibility, it raises obvious questions. Tools from other institutions explicitly include “impossible sighting” logic based on topocentric constraints, illustrating how common that filtering mindset is in the astronomy side of the discussion.
Other tools on the site: prayer times, qibla, and calendar material
Although the name points to crescent sighting, Moonsighting.com also offers a set of practical utilities: prayer times, qibla direction, and a large amount of calendar-related content. The site frames itself as supporting a broader goal of publishing Hijri calendar information and working toward more standardized approaches, while still grounding the discussion in observed reports.
This mix is part of why the site remains sticky: people arrive for Ramadan/Eid, then also use adjacent tools like city-based prayer schedules or qibla direction when they’re already there.
Strengths and limitations to keep in mind
The biggest strength is continuity. The site emphasizes that it has been collecting and publishing reports for decades and pairing them with predicted visibility information, which is exactly what you want if your goal is to compare “what was predicted” with “what was reported” over many cycles.
The limitation is that no single site can resolve the underlying jurisprudential disagreement. Even perfect maps and perfect reporting wouldn’t force agreement, because different communities use different rules: local vs global sighting, accepting telescopic sightings vs naked-eye only, and how much weight to give calculation. So the best way to use Moonsighting.com is as evidence and context—what was seen where, what the geometry suggested, and how that lines up with your community’s adopted method—rather than expecting it to settle disputes by itself.
Key takeaways
- Moonsighting.com collects global crescent sighting reports and pairs them with prediction tools like visibility maps and curves.
- Its reporting network is organized through the Moonsighting Committee Worldwide (MCW), which invites members to submit observations.
- Visibility maps are based on astronomical criteria used across the broader crescent-visibility field (with methods such as Yallop commonly referenced in the wider ecosystem).
- Ramadan/Eid prediction pages reflect chosen rule sets (visibility thresholds + geographic scope), not a universally binding outcome.
- The site is most useful as shared context for decision-making, not as a single authority that ends disagreement.
FAQ
Is Moonsighting.com an “official” authority for starting Ramadan or Eid?
No single global “official” body governs this for all Muslims. The site provides reports and prediction tools that organizations may consult, but different communities still follow their own adopted methodologies.
Does astronomical new moon (conjunction) mean the month has started?
Conjunction is a precise astronomical moment, but the Islamic month traditionally begins with the sighting of the new crescent (or completion of 30 days). Visibility depends on location and conditions, so conjunction alone doesn’t guarantee the crescent can be seen.
What are crescent visibility maps good for if people still physically sight the moon?
They help set expectations, plan sighting efforts, and flag implausible claims. Many communities use calculations as supporting evidence even if they still require an actual sighting.
Can I join MCW and submit moon sighting reports?
The site publishes instructions for joining MCW and sharing your location and contact details, so you can participate if you want to contribute reports.
Why do different countries or mosques celebrate Eid on different days even with the same sky?
Because they use different rules: local sighting vs global sighting, what counts as “acceptable” testimony, and how much calculation is allowed to override reports. The disagreement is methodological, not just astronomical.
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