Sky Brightness Measurement for the Construction of the Astronomy Observatory Branch of Universitas Muhammadiyah Sumatera Utara (OIF UMSU) in Barus, Central Tapanuli Regency, Indonesia
Light pollution at Astronomy Observatory of UniversitasMuhammadiyah Sumatera Utara (OIF UMSU) has spread in all directions so that OIF UMSU plans to build a branch of it in Barus, Central Tapanuli Regency, Indonesia. This research is an experimental study in the form of observing the level of sky brightness using the Sky Quality Meter (SQM). Data was collected at KedaiTiga Beach, Barus District, CentralTapanuli Regency since 24 until 29 February, 2020. The average value of maximum sky brightness obtained was 21.67 mpsas and had level of difference at 2.65 mpsas with the sky at OIF UMSU. So it can be said that the sky in Barus is 11.5 times darker than the sky at OIF UMSU. The sky's brightness in Barus falls into the first category on the Bortle scale (> 21.3 mpsas) which is an ideal location for an observatory location because it has less light pollution so it can observe celestial bodies better than at the current UMSU OIF location.