DIY Photometer Performance Test in Determining Morning Twilight

Abstract

Abstract Do-It-Yourself (DIY) Sky Quality Meter (SQM) known as D.I.Y – CJ’01 Photometer has been successfully built and tested. Using SQM as a calibrated portable photometer is a hot topic of astronomical research regarding night sky brightness measurement. The output data obtained by the photometer is in unit of magnitude per square arc second (mag/sq arcsecond ∼ mpsas) value with a maximum value of 21.7 mpsas as a quantization of the representation of a very dark sky with the presence of natural airglow. The sky brightness then gradually increases with values up to 16.7 mpsas, which is when the sky is brighter due to the presence of artificial airglow from outdoor artificial lighting such as in big cities. This research aims to determine the D.I.Y – CJ’01 Photometer performance in measuring the sky brightness of morning twilight. The research method used in this work is an experiment with data collection from D.I.Y - CJ’01 Photometer and SQM Unihedron gathered from two locations in Cimahi and Bandung. Data processing shows that the D.I.Y - CJ’01 Photometer mimics the performance of SQM Unihedron, with the the smallest difference for the value of the solar depression angle in morning twilight measurements is 0.06%.