Hijri Calendar Guide: Conversion and Lunar Sighting (2026)
Learn how to convert Gregorian dates to Hijri dates. Read about calculation algorithms, moon sighting guidelines, and astronomical cycles.
Calculating Lunar Dates
Converting Gregorian dates to Hijri dates requires combining astronomical calculations with crescent visibility criteria. While modern computers estimate Hijri dates, physical moon sighting remains the theological standard.
Key Takeaways for Sighting & Math
| Criterion | Details |
|---|---|
| Elongation Angle | The moon must be at least 7° away from the sun to form a visible crescent. |
| Moon Age | Usually needs to be at least 15 to 24 hours old to be visible. |
| Sunset Altitude | The moon must remain above the horizon after sunset for visibility. |
Moon Sighting vs. Math
Algorithmic calendars like the Saudi Umm al-Qura system are highly accurate for administrative planning. However, physical confirmation of the new crescent moon by local Shariah committees remains the definitive method for religious events.
This guide has been verified by our editorial board. Astronomical data matches calculated equational metrics, and liturgical instructions conform with established traditional jurisprudential Fiqh sources.
Frequently Asked Questions
Academic & Shariah References
- Astronomical Algorithms by Jean Meeus
- Umm al-Qura University Calendar Documentation
About The Author
Dr. Sarah Jenkins holds a PhD in Astrophysics from Oxford University. She specializes in solar positioning algorithms and coordinates calculations for geographical mapping platforms.