Digital Hilal Observation: Evaluating the Authenticity of Hilal Testimonials in Indonesia Using the Digistar-6 Planetarium System

Abstract

This article aims to provide supporting data to test the authenticity of testimonial claims of sighting the hilal (new moon) that have been received and decided by the Ministry of Religious Affairs of the Republic of Indonesia (RI) from 1962-2021 during the isbat session for the determination of the beginning of the months of Ramadan, Shawwal, and Dhu al-Hijjah. Building upon the results of the author's previous research that revealed inconsistencies in the application of the minimum visibility criteria for the hilal known as imkan al-rukyat by the Ministry of Religious Affairs Indonesia. Approximately 45.5% of the hilal testimonial claims found in the Minister of Religious Affairs' decisions are doubted for their authenticity due to various reasons, including the absence of elongation data and the presence of hilal altitude data below the Ministers of Religious Affairs of Brunei Darussalam, Indonesia, Malaysia, and Singapore (MABIMS) criteria. To substantiate the old data, this article employs the Digistar-6 planetarium system to provide a scientifically accurate 3D visualization of the hilal observation process through a full-dome planetarium. Using a qualitative descriptive approach, this article examines all the testimonial claims data after classifying them based on the application of the imkan al-rukyat theory in MABIMS in Indonesia. The findings show several key points: First, there is no elongation data available in all of these decisions. Second, there is a variation in the use of astronomical calculations for hilal data, especially before the implementation of MABIMS criteria. Third, there is astronomical data on hilal claims post the implementation of MABIMS criteria that are accepted with altitudes below 2°. Fourth, the tendency is that the hilal can be seen with optical aids during hilal altitudes above 3° and elongations exceeding 6°.