Sky brightness and lunar illumination at PERMATApintar observatory

Abstract

This research presents preliminary findings of night sky brightness at the PERMATApintar??? Observatory. The measurements were made using the Unihedron Sky Quality Meter (SQM-LU) attached to the top of a camera tripod. The Sky Quality Meter was directed towards zenith. The data were logged continuously throughout the night from 1910 hours until 0730 hours the next day for three nights. The value of sky brightness was measured every 3 seconds using the Unihedron Device Manager software. The sky brightness and the lunar altitude were then plotted as a function of time using Microsoft Excel for analysis. The results showed that night sky brightness decreases as the lunar altitude decreases; that the night sky brightness is maximum when the Moon is at zenith; and that the night sky brightness is maximum when the Moon is in the full moon phase. The mean value of night sky brightness during the observation is 18.0 mag/arcsec/. Even though measurements were made for three nights only, this result can be used for future reference because the data collected during these three nights have minimal differences between them. This study could be improved by taking account other factors that affects night sky brightness such as the presence of artificial lights and cloud cover.