Feasibility Study of the Rooftop of the Research Center Building at the State Islamic University of Mataram as a Location for Rukyatul Hilal

Abstract

Abstract: This study aims to evaluate the feasibility of the UIN Mataram Research Center building as a site for moon sighting (rukyatul hilal) based on geographic and meteorological conditions. The research uses a descriptive qualitative method, including direct field observations, data from the Meteorology, Climatology, and Geophysics Agency (BMKG), and analysis of accessibility, light pollution, western horizon visibility, and elevation. Geographically, the Research Center is in the center of Mataram city at coordinates 8° 36' S and 116° 8' E, about 3 km from the coast with a clear view to the northwest. The building is easily accessible and has a stable internet connection. However, the area has high light pollution (Bortle scale class 5), which can interfere with moon visibility. The view to the west is blocked by structures like power poles at 265°, a power plant at about 287°, and Mount Agung at about 293°, making it less ideal for moon sighting. Weather-wise, the study analyzed rainfall and humidity data from 2021 to 2023. Mataram experiences varying rainfall, with some months having very high rainfall that can obstruct moon observation. High humidity levels also create clouds and fog, reducing visibility. Based on these findings, the researchers concluded that the UIN Mataram Research Center building is not suitable for moon sighting due to its geographic and weather conditions.