International Astronomical Center V-criterion (2004)
M.Sh. Odeh · Experimental Astronomy 18(1-3)Published by Mohammad Sh. Odeh of the International Astronomical Center (IAC) in 2004, this criterion is a modern statistical refinement of the Yallop method. It uses a larger, more globally representative dataset of crescent sighting observations and derives a V-parameter from the Arc of Vision (ARCV) and crescent width (W').
Odeh's criterion uses slightly shifted polynomial thresholds compared to Yallop, which can sometimes yield more conservative (less optimistic) predictions in marginal cases. It is widely used by the IAC and adopted by several national and international bodies.
| Aspect | Yallop (1997) | Odeh (2004) |
|---|---|---|
| Dataset size | Smaller historical dataset | Larger global dataset |
| Classification codes | A, B, C, D, E (5 zones) | NE, OA, NV (3 zones) |
| Polynomial threshold | 11.8371 − 6.3226W + 0.7319W² − 0.1018W³ | 7.1651 − 6.3226W + 7.0952W² − 0.3310W³ |
| Boundary shift | Reference threshold | Slightly more conservative in marginal zones |
| Published by | HM Nautical Almanac Office (UK) | International Astronomical Center (UAE) |
| Code | Meaning | V Parameter | Map Colour |
|---|---|---|---|
| NE | Naked Eye Visible | V ≥ 5.65 | ■ Green |
| OA | Optical Aid Required | −0.96 ≤ V < 5.65 | ■ Yellow |
| NV | Not Visible even with optical aid | V < −0.96 | ■ Red |
This platform provides astronomical modelling of crescent visibility based on the Odeh V-criterion. Results are probabilistic and for educational purposes only. Final religious decisions remain with local authorities.