Sky Brightness at Weihai Observatory of Shandong University

TL;DR

This study analyzes 28,000 images from Weihai Observatory to characterize sky brightness variations, revealing impacts of moonlight, twilight, and urban light, with seasonal and positional dependencies.

Contribution

It provides a comprehensive database of sky brightness measurements at Weihai Observatory and analyzes its variation with sky position, moonlight, and season, highlighting urban light pollution effects.

Findings

Darkest sky brightness around 19.0 mag/arcsec^2 in V band

Significant sky brightness variation with azimuth and season

Urban light significantly influences sky brightness at WHO

Abstract

In this paper, a total of about 28000 images in $V$ and $R$ band obtained on 161 nights using the one-meter optical telescope at Weihai Observatory (WHO) of Shandong University since 2008 to 2012 have been processed to measure the sky brightness. It provides us with an unprecedented database, which can be used to study the variation of the sky brightness with the sky position, the moonlight contribution, and the twilight sky brightness. The darkest sky brightness is about 19.0 and 18.6 $mag$ $arcsec^{-2}$ in $V$ and $R$ band, respectively. An obvious darkening trend is found at the first half of the night at WHO, and the variation rate is much larger in summer than that in other seasons. The sky brightness variation depends more on the azimuth than on the altitude of the telescope pointing for WHO. Our results indicate that the sky brightness at WHO is seriously influenced by the urban light.