Light pollution disturbance in detecting zodiacal light and twilight

It has been analyzed 285 light curve SQM (Sky Quality Meter) data for night sky conditions until dawn in clear conditions and without moonlight interference in 20 locations. The observation locations were divided into four categories: dark, slightly dark, slightly bright, and bright. By comparing the darkness of the observation locations, it is concluded that the visibility of the zodiacal light and the astronomical twilight is affected by light pollution. Statistical analysis shows that 77% of astronomical twilight is affected by light pollution at the observation site. The impact of light pollution on the sun’s altitude at dawn is described by the equation y=0.55 x+11.12 ± 1.45, where y is the brightness of the night sky (in mpsas) and x the sun’s altitude at the beginning of twilight (in degrees). This equation means that if there are reports of the beginning of twilight when the sun’s position is higher, it is caused by light pollution which causes the sky getting brighter. This study obtained that the average sun’s altitude at the beginning of twilight in the dark area is −19.40 ± 0.53 degrees. Light pollution also affects the appearance of the zodiacal light. The appearance of the zodiacal light is indicated by the slope pattern of the light curve which shows that the eastern horizon is slowly getting brighter. In dark areas, the zodiacal light is clearly visible with a linearly decreasing light curve pattern. In bright areas, the slope pattern does not exist because light pollution dominates with a constant pattern.