ANALYSIS OF SKY BRIGHTNESS VARIATIONS IN FULL DAYS BASED ON SKY QUALITY METER MEASUREMENT IN PEKALOGAN

• Main Author: Salma, Akniz
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/75493
• Institution: Institut Teknologi Bandung

The brightness of the night sky has an ecological impact, especially on nocturnal animals. Similarly, the transition between nights-days and vice versa as a period of fajr/dawn that affects crepuscular animals. The sky brightness affects field of astronomy so it is necessary to take measurements continuously. The sky brightness is slower to lighten at dawn and slower to darken at dusk which can be affected by light pollution sourced from human activities, meteorological, and natural factors (Moon phase and zodiacal light). Quantization of the sky brightness continuously in a full days based on the function of light pollution, Sun position, and length of the shadow in the daytime are important to do. Analysis of the sky brightness at the limits of the beginning of dawn, the end of dusk, the sunrise/sunset, during mid-morning/evening, and the time of culmination are useful for testing the Islamic prayers time. Measurement of sky brightness in a full days has been done using Sky Quality Meter photometer at coordinates 6?50'42" south latitude 109?37'55" east longitude for 25 days with 3 seconds retrieval resolution that installed neutral density variable and battery. Analysis of sky brightness data was carried out using Difference, Moving average, and Polynomial methods. This research concludes that the sky brightness during twilight shows relatively small variation, with the beginning of dawn identified at -15,301? of Sun elevation and the end of dusk at -18,853? of Sun elevation. The sky brightness profiles before and after 12 noon are asymmetrical. In the evening, the average difference sky brightness at shadow lengths of 1 to 2 is 0,9 MPSAS with 0,39 standard deviation and the average shadow length of object during fluctuations is 1,36 . The average difference in sky brightness at noon compared to midnight sky is 9,02 MPSAS.