Question 1

What is the Odeh criterion for moon visibility?

Accepted Answer

The Odeh V-criterion (developed by Mohammad Odeh in 2006) is a scientifically validated method for predicting lunar crescent visibility. It categorizes visibility into four zones: Easily Visible (EV), Visible under Perfect conditions (VP), Visible with Optical aid (VO), and Not Visible (NV). This criterion is widely used for Islamic calendar calculations and Hijri date determination.

Question 2

How accurate is the Odeh lunar calendar calculator?

Accepted Answer

Our Odeh lunar calendar uses the Odeh V-criterion combined with precise astronomical calculations via the astronomy-engine library. It provides highly accurate predictions for moon visibility with a 2°×2° global grid resolution, accounting for sunset times, moon position, and atmospheric conditions at over 70 major cities worldwide.

Question 3

Can I use this for Hijri calendar calculations?

Accepted Answer

Yes! This tool generates accurate Hijri calendar dates based on actual moon visibility using the Odeh criterion. It determines the first night of each Islamic month by detecting when the lunar crescent becomes visible at your location, either through direct sighting or shared night inheritance.