In determining the start of the Hijriah month, the elongation of the\ncrescent plays a vital role as a physical parameter for the visibility\nof the new moon. Without an adequate elongation angle, the crescent\noptically cannot reflect enough light to penetrate the twilight glow of\nthe setting sun (syafaq).<\/p>\n
Elongation is the angular distance between the Moon and the Sun as\nseen from Earth. In the context of rukyatul hilal (crescent sighting),\nelongation determines the thickness of the moon\u2019s crescent. The larger\nthe elongation angle, the thicker the visible crescent, and the greater\nthe chance of it being observed by sighters.<\/p>\n
Based on the agreement of the Ministers of Religious Affairs from\nBrunei, Indonesia, Malaysia, and Singapore (MABIMS), the minimum\ncriteria for the crescent to be declared as marking the new month are an\nelongation of 6.4 degrees and a height of 3 degrees.<\/p>\n
There are two methods for calculating the elongation angle, which\noften become subjects of discussion among falak (Islamic astronomy)\nexperts.<\/p>\n
The choice of 6.4 degrees is not arbitrary. This figure refers to the\nDanjon Limit, where the moon\u2019s crescent physically begins to form and\ncan reflect light. If the elongation is below this number, even if the\nmoon is above the horizon (positive height), scientifically, the\ncrescent is considered not yet \u201cexistent\u201d for human eyesight (imkanur\nrukyat).<\/p>\n
This figure is based on empirical data from global observations\nshowing that crescents with elongation below 6.4 degrees are too thin,\nand their light is overwhelmed by the background light of the evening\nsky.<\/p>\n
Height is the vertical distance of the crescent from the horizon line\n(cakrawala), while elongation is the direct angular distance between the\nMoon and the Sun. Both must be met for the crescent to be considered\nvisible.<\/p>\n
It is very difficult. If the height is too low (below 3 degrees),\natmospheric interference and the still-bright syafaq light will obscure\nthe appearance of even a thick crescent.<\/p>\n
Understanding crescent elongation helps us realise that the\ndetermination of the Hijriah month start in Indonesia is done with a\nhighly precise scientific approach. The combination of hisab data\n(calculations) and rukyat verification (observations) ensures that\nMuslim worship begins at the appropriate time both astronomically and in\naccordance with sharia.<\/p>\n
The Ministry of Religious Affairs in Maluku reported that the 1\nSyawal 1447 H crescent failed to be seen in the Land of Wakasihu because\nits position was still below 2 degrees.<\/p>\n
The Ministry of Religious Affairs reported that the position of the 1\nSyawal 1447 H crescent across Indonesia did not meet MABIMS criteria.\nSee the full astronomical analysis.<\/p>\n
See the latest 2026 MABIMS criteria for determining Ramadan and Eid\nal-Fitr. Understand the parameters of 3-degree crescent height and\n6.4-degree elongation in full.<\/p>\n
The Ministry of Religious Affairs set the start of fasting for 1\nRamadan 2026 on Thursday, 19 February. The Isbat session decision was\nbased on MABIMS criteria and crescent results.<\/p>\n
See the reasons why MABIMS criteria are the main reference in the\n2026 Isbat session for determining the start of Ramadan 1447 H\nscientifically and legally.<\/p>\n
Why must there be an Isbat session to determine Eid? See the full\nexplanation from the perspectives of state law, religious sharia, and\nastronomical science.<\/p>\n
If viewed from the illustration of the crescent\u2019s position on the\nwestern horizon, all provincial capitals in Indonesia are below MABIMS\ncriteria.<\/p>\n
For the first time, IKN became the location for rukyatul hilal to\ndetermine 1 Ramadan 1447 H. The BMKG East Kalimantan stated that the\ncrescent was not visible because it was still below the horizon.<\/p>\n
The crescent monitoring team from the BMKG Class III Geophysics\nStation in Malang reported that the crescent phenomenon was not visible\nin the Malang area, East Java, in the afternoon on Tuesday (17\/2).<\/p>\n
Observation locations are selected selectively, considering the\nopenness of the western horizon, minimal light pollution, good\natmospheric conditions, as well as accessibility and security of the\nlocation.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/elongation-of-the-crescent-in-islamic-astronomy-definition-and-role-in-the-isbat-session-1773924692", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }