On 9 October 2023, Jakarta will experience a phenomenon known as the “Day Without Shadows.” This marks the second occurrence of the Main Culmination of the year in Jakarta, with the previous one taking place on 5 March 2023.
Information regarding the Main Culmination of the Sun, also known as the “Day Without Shadows” in 2023 in Indonesia, has been shared by the Meteorology, Climatology, and Geophysics Agency (BMKG).
According to BMKG, the Main Culmination phenomenon, or the “Day Without Shadows,” will occur in DKI Jakarta on Monday, 9 October 2023. Specifically, BMKG mentions that the “Day Without Shadows” on 9 October 2023 will happen at approximately 11:40 AM Western Indonesia Time (WIB).
The “Day Without Shadows” occurs because the Earth’s equatorial plane, or the Earth’s rotational plane, does not exactly coincide with the ecliptic plane, or the Earth’s orbital plane. This causes the position of the Sun relative to the Earth to continuously change throughout the year, between 23.5 degrees north latitude and 23.5 degrees south latitude. This phenomenon is known as the Sun’s apparent daily motion.
“Specifically for the city of Jakarta, this phenomenon occurred on 5 March 2023, with the main culmination happening at 12:04 PM WIB, and on 9 October 2023, with the main culmination occurring at 11:40 AM WIB,” as stated by BMKG in its official release on the “Main Culmination 2 in Indonesia in 2023.”
Here is the complete schedule for the “Day Without Shadows” phenomenon in Jakarta on 9 October 2023:
– Jakarta Pusat (Central Jakarta): 9 October 2023, at 11:40:05 WIB
– Jakarta Utara (North Jakarta): 9 October 2023, at 11:39:44 WIB
– Jakarta Timur (East Jakarta): 9 October 2023, at 11:40:05 WIB
– Jakarta Selatan (South Jakarta): 9 October 2023, at 11:40:13 WIB
– Jakarta Barat (West Jakarta): 9 October 2023, at 11:40:28 WIB.
Here is the complete schedule of the Main Culmination or “Day Without Shadows” phenomenon for the second quarter of 2023 in all regions of Indonesia, according to data from BMKG:
Banda Aceh: 9 September 2023, at 12:36:14 WIB
Medan: 14 September 2023, at 12:21:01 WIB
Padang: 25 September 2023, at 12:10:25 WIB
Pekan Baru: 22 September 2023, at 12:07:07 WIB
Bengkulu: 3 October 2023, at 12:00:09 WIB
Jambi: 27 September 2023, at 11:56:44 WIB
Tanjung Pinang: 21 September 2023, at 11:55:30 WIB
Palembang: 1 October 2023, at 11:50:48 WIB
Bandar Lampung: 7 October 2023, at 11:46:56 WIB
Pangkal Pinang: 29 September 2023, at 11:46:03 WIB
Serang: 9 October 2023, at 11:42:47 WIB
Central Jakarta: 9 October 2023, at 11:40:05 WIB
Bandung: 11 October 2023, at 11:36:27 WIB
Semarang: 11 October 2023, at 11:25:06 WIB
Yogyakarta: 13 October 2023, at 11:24:54 WIB
Surabaya: 12 October 2023, at 11:15:46 WIB
Pontianak: 23 September 2023, at 11:35:13 WIB
Palangka Raya: 29 September 2023, at 11:14:57 WIB
Banjarmasin: 2 October 2023, at 12:11:09 WITA
Samarinda: 24 September 2023, at 12:03:45 WITA
Tanjung Selor: 16 September 2023, at 12:05:36 WITA
Denpasar: 16 October 2023, at 12:04:50 WITA
Mataram: 15 October 2023, at 12:01:30 WITA
Kupang: 20 October 2023, at 11:30:35 WITA
Mamuju: 30 September 2023, at 11:54:37 WITA
Makassar: 6 October 2023, at 11:50:36 WITA
Palu: 25 September 2023, at 11:52:28 WITA
Kendari: 3 October 2023, at 11:39:08 WITA
Gorontalo: 22 September 2023, at 11:40:42 WITA
Manado: 19 September 2023, at 11:34:38 WITA
Sofifi: 21 September 2023, at 12:23:03 WIT
Ambon: 3 October 2023, at 12:16:30 WIT
Manokwari: 25 September 2023, at 11:55.36 WIT
Jayapura: 30 September 2023, at 11:27:24 WIT.
Understanding the “Day Without Shadows” Phenomenon
Quoting BMKG, the “Day Without Shadows” is a term used for the Main Culmination phenomenon. Culmination, transit, or istiwa’ is the phenomenon when the Sun is at its highest point in the sky. When the Sun’s declination is equal to the observer’s latitude, this phenomenon is referred to as the Main Culmination.
During this time, the Sun will be directly overhead or at the zenith point. As a result, the shadow of an upright object will appear to “disappear” for about 30 seconds before and after the peak time in each region, as it aligns with the object itself. This is why the Main Culmination Day is known as the “Day Without Shadows.”
These events offer unique opportunities to observe the Main Culmination phenomenon or “Day Without Shadows” throughout Indonesia, where the Sun reaches its zenith, resulting in momentary shadow disappearance.
