Isbat Session to Determine Start of Ramadan Set to Be Held: Predicted Crescent Moon Position Today
The Ministry of Religious Affairs (Kemenag) is holding the isbat session to determine the start of Ramadan 1447 H/2026 today. What is the crescent moon’s position ahead of the session?
As reported by the Public Relations and Communications Bureau of the Ministry of Religious Affairs and the official Instagram account of the Directorate General of Islamic Community Guidance (Ditjen Bimas Islam) on Tuesday (17 February 2026), the isbat session will be held at Hotel Borobudur, Central Jakarta. The session is scheduled for 18:30 Western Indonesian Time (WIB) and will be broadcast live on the Bimas Islam TV and Kemenag YouTube channels.
The isbat session will involve broad representation from the Muslim community, including Islamic organisations such as Nahdlatul Ulama (NU), Muhammadiyah, Persis, Al-Irsyad Al-Islamiyyah, Hidayatullah, and the Islamic Unity Association (PUI), as well as experts in Islamic astronomy (falak) and modern astronomy from various institutions including BMKG, BRIN, the Planetarium, and astronomical observatories.
The holding of the isbat session today means the start of Ramadan 1447 H is predicted to fall on 18 February 2026 if the crescent moon (hilal) is declared to have met the required criteria. If the hilal has not met the criteria, the start of Ramadan 1447 H may be set for the following day, 19 February 2026.
Indonesia uses standards agreed upon by the Ministers of Religious Affairs of Brunei Darussalam, Indonesia, Malaysia, and Singapore (MABIMS) for determining the hilal. According to the Kemenag website, the new MABIMS criteria stipulate that the possibility of sighting (imkanur rukyat) is considered fulfilled when the hilal reaches an altitude of 3 degrees with an elongation angle of 6.4 degrees.
The following is the predicted hilal position from BMKG:
- Geocentric Conjunction
The conjunction or ijtima’ is the event when the ecliptic longitude of the moon equals the ecliptic longitude of the sun as observed from the centre of the Earth. This event will occur on Tuesday, 17 February 2026, at 19:01:07 WIB, when the ecliptic longitude values of both the sun and moon are exactly 328.83 degrees.
The synodic period of the moon, counted from the previous conjunction (beginning of Sha’ban 1447 H) to the upcoming conjunction (beginning of Ramadan 1447 H), is 29 days, 16 hours, and 9 minutes. Sunset is defined as when the upper edge of the solar disc is exactly at the observed horizon.
Because the conjunction occurs after sunset on 17 February 2026, astronomically the hilal observation to determine the start of Ramadan 1447 H — for those who apply physical sighting (rukyat) — should take place after sunset on 18 February 2026. Meanwhile, for those who apply astronomical calculation (hisab) in determining the start of Ramadan 1447 H, the hisab criteria at sunset on 18 February 2026 need to be calculated.
- Hilal Altitude
The hilal altitude across Indonesia at sunset on 17 February 2026 ranges from -2.41 degrees in Jayapura, Papua, to -0.93 degrees in Tua Pejat, West Sumatra. The hilal altitude across Indonesia at sunset on 18 February 2026 ranges from 7.62 degrees in Merauke, Papua, to 10.03 degrees in Sabang, Aceh.
- Elongation
The geocentric elongation across Indonesia at sunset on 17 February 2026 ranges from 0.94 degrees in Banda Aceh, Aceh, to 1.89 degrees in Jayapura, Papua. The geocentric elongation across Indonesia at sunset on 18 February 2026 ranges from 10.7 degrees in Jayapura, Papua, to 12.21 degrees in Banda Aceh, Aceh.
- Lunar Age
The lunar age across Indonesia at sunset on 17 February 2026 ranges from -3.07 hours in Jayapura, Papua, to -0.16 hours in Banda Aceh, Aceh. The lunar age across Indonesia at sunset on 18 February 2026 ranges from 20.92 hours in Jayapura, Papua, to 23.84 hours in Banda Aceh, Aceh.