New approach on study of new young crescent (Hilal) visibility and new month of Hijri calendar

Abstract

We present a preliminary result on criteria of a young moon crescent visibility and the beginning of new month in Hijri calendar. We present our study of all possibility of moon's astronomical position at sun-set time in one diagram. The altitude of the moon vs the elongation between the moon and the sun, and the azimuth differences between the sun and the moon plotted over the diagram. The purpose of constructing the diagram is to see easily all used/proposed criteria of the beginning of the Hijri' month on a single diagram, then the position of the new young crescent of the moon on the diagram can be analysed easily, whether it is included in criteria of young moon crescent (hilal) visibility or excluded. Some cases of Hijri calendar of 2017 - 2018 in Indonesia are examined and provided in this paper.