JAKARTA - The decision of the Isbat Session to determine 1 Ramadan 1447 H by the Ministry of Religion of the Republic of Indonesia is based on astronomical data which is considered very strong. Minister of Religion Nasaruddin Umar emphasized that technically, the crescent in all regions of Indonesia has not even "born" above the horizon when the sun sets.
The calculation data shows that the position of the crescent moon is at a very low point, even touching minus 2 degrees at a number of observation points. In the presentation of the Isbat Session, the Minister of Religion explained that the position of the crescent moon throughout the Indonesian archipelago ranges from minus 2 degrees 64 minutes to 0 degrees 48 minutes. This condition is scientifically referred to as ghairu wujudul hilal or the crescent moon that has not yet materialized.
"Hilal data at the position of hisab throughout Indonesia shows a very low altitude. In terms of hisab, the crescent is not visible above the horizon," said Nasaruddin Umar.
According to the MABIMS criteria used by Indonesia, the new crescent is considered to meet the visibility requirement if it is at a minimum height of 3 degrees with an elongation angle of 6.4 degrees. In addition to the negative height, the elongation angle or angular distance between the moon and the sun is also very minimal, namely only in the range of 0 degrees 56 minutes to 1 degree 53 minutes.
"This data shows that the distance of the moon is still too close to the sun, so it is impossible to be seen by the human eye or optical instruments at our 96 observation points," he added.
Because the position of the crescent does not meet these criteria, the month of Syakban is completed to 30 days or istikmal. Thus, 1 Ramadan 1447 H is set to fall on Thursday, February 19, 2026.
In detail, the largest hilal height on February 17, 2026 was recorded in Sabang, Aceh with a hilal height of minus 1 degree 41 minutes, while the lowest occurred in Jayapura, Papua with minus 3 degrees 12 minutes. In Jakarta, specifically at the PBNU Building, Jalan Kramat Raya, the hilal height was recorded at minus 1 degree 44 minutes 39 seconds.
The Ijtimak or conjunction itself occurred on Tuesday, February 17, 2026 at 19.02.02 WIB based on the calculation of the falak method (hisab) of contemporary tadqiki ashri tahqiqi typical of Nahdlatul Ulama.
Meanwhile, the Meteorology, Climatology, and Geophysics Agency (BMKG) also released information on the predicted hilal when the sun sets on February 17 and 18, 2026. BMKG said the conjunction occurred on Tuesday, February 17, 2026 at 12.01.07 UT or 19.01.07 WIB.
By taking into account the conjunction time and sunset time, BMKG concluded that on February 17, 2026, the hilal was still below the horizon in all regions of Indonesia, with a height ranging from minus 2.41 degrees in Jayapura to minus 0.93 degrees in Tua Pejat, West Sumatra.
On the other hand, on February 18, 2026, the height of the crescent will be in the range of 7.62 degrees in Merauke to 10.03 degrees in Sabang, with a geocentric elongation between 10.7 degrees to 12.21 degrees. These data show that astronomically, the new crescent meets the visibility criteria the next day, so the beginning of Ramadan is set for February 19, 2026.
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