Implikasi kriteria visibilitas hilal rekomendasi Jakarta 2017 terhadap penanggalan hijriah di Indonesia

Young Crescent (hilal) is used as a reference in various lunar calendar systems, for example the calendar of Hijri / Islam, Hinduism, Judaism, and so on. In an effort to realize the unity of the people with a globally unified calendar and minimize differences between countries in the implementation of worship based on the determination of the beginning of the Hijri month, a single criterion is proposed, namely a minimum hilal height of 3 degrees and a minimum elongation of 6.4 degrees called the Jakarta recommendation. The 2017 Jakarta recommendation is a compromise of Islamic dating criteria with the latest results from the empirical thinnest observation of the hilal observation data. This proposed new criteria conditions the new moon to estimate the new moon position which is higher than the previous MABIMS criteria. From the preliminary study on the determination of the beginning of the Islamic calendar in 1440, there were differences in the determination between the Jakarta recommendations and the MABIMS criteria of 3 months, namely Safar, Jumadil Awal, and Zulhijjah. The difference does not include differences between the determination of MABIMS and wujudul hilal for 2 months, namely Rabiul Akhir, and Syaban. This study can illustrate the possibility of early differences in the determination of the month in the Islamic calendar due to the existence of several criteria used.