The new hilaal visibility criterion for tropical region

We propose a new Hilaal (lunar crescent formed immediately after conjunction) visibility criterion apply to tropical region utilizing modified mathematical model of near-sun objects visibility. By using only naked eye positive sightings of Hilaal, then we are calculating the Moon and Sun observation parameters to obtain the visibility function for each case. Moon - Sun altitude difference (ARCV - Arc of Vision) and elongation (ARCL - Arc of Light) at the first observable moment have been chosen as parameters and used in developing new visibility criterion. The data show that the minimum ARCV and ARCL value for naked eye observation at the moment of Hilaal is observed are 8.4° and 7.1°, respectively. Our results can be proposed as a scientifically criterion for constructing Hijri calendar for tropical region (including Indonesia) as an alternative to Jakarta Recommendations criterion.