Bosscha Observatory Conducts Hilal Observation for the Beginning of Ramadan 1443 H

Oleh Adi Permana

Editor Adi Permana

BANDUNG, itb.ac.id - As an institute for education and research in the astronomy field, Bosscha Observatory of Institut Teknologi Bandung has been conducting observations of the young crescent moon almost every month.

Every year, Bosscha Observatory becomes one of the references for setting the beginning date of Ramadan and Shawwal for the Ministry of Religious Affairs and the general public. Bosscha Observatory conducted the crescent moon observation on April 1, 2022, which is considered as a mark for the shift of the month of Shaban to the month of Ramadan 1443 H.

Observation conducted at Lembang

The Bosscha Observatory Team carried out the observation of hilal at the Bosscha Observatory, Lembang, from March 29 to April 2, 2022, from daytime until moonset on the Western horizon.

This crescent moon observation activity conducted by Bosscha Observatory is aimed to examine the visibility function of the moon as a function of the elongation and thickness of the crescent moon, and also in the event of rukyatul hilal in the month of Ramadan 1443 H. Rukyatul hilal takes place during the evening and crescent moon detection takes place after sunset. The crescent that appears after sunset is known as ‘hilal’.

This observation took place by using a 106 mm refractor telescope equipped with a CCD type camera detector. The image caught by the camera is then processed by an image processing device to enhance the appearance of the crescent moon. This activity was an internal observation that was only attended by the Bosscha Observatory staff to follow the guideline of not being part of any activities that involves a large party of people in a single place. Anyone of the general public who are interested could watch this hilal sighting online through live streaming on Bosscha Observatory’s official YouTube channel on April 2, 2022, which started from 17.00 WIB.

Deciding the beginning of Ramadan and Shawwal

In Indonesia, the party responsible for deciding the beginning of Ramadan and Shawwal is the Republic of Indonesia’s government through a itsbat trial process.

The task of the Bosscha Observatory is to convey the calculation, observation and study results regarding hilal to the government unit responsible if needed as input for the itsbat trial. The general public are able to access the data and results of the observation of hilal in the Bosscha Observatory’s website https://bosscha.itb.ac.id.

Attachment of Hilal Ramadan 1443H Data – Bosscha Observatory, Lembang

Coordinates: 6° 49' 50" LS, 107° 37' 00" BT; Time: (UTC+7 Time); height: 1310 AMSL.
Friday, April 1, 2022

*Moon and Sun configuration during sunset Friday, April 1, 2022


*Map of moon’s height during sunset Friday, April 1, 2022


Source: Bosscha ITB Observatory Release

Reporter: Adi Permana
Translator: Hanna Daniela Ayu (Faculty of Mechanical and Aerospace Engineering, 2021)


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