The i-band Sky brightness and Transparency at Dome A, Antarctica

TL;DR

This study analyzes the sky brightness and transparency at Dome A, Antarctica, using CSTAR observations, revealing median sky brightness, cloud conditions, aurorae effects, and overall observing quality for the i band.

Contribution

It provides the first detailed assessment of sky conditions at Dome A in the i band, including brightness, transparency, and aurorae influence, based on a year's observational data.

Findings

Median sky brightness of 20.5 mag arcsec$^{-2}$ during moonless clear nights

No thick clouds observed in 2008

Aurorae can brighten the sky by up to 2 magnitudes in images

Abstract

Based on the observations of the Chinese Small Telescope ARray (CSTAR), the i band observing conditions at Antarctic Dome A have been investigated. The over all variations of sky brightness and transparency are calculated and subsequently cloud cover, contributions to the sky background from various factors including aurorae are derived. The median sky brightness of moonless clear nights is about 20.5 mag arcsec$^{-2}$ in the SDSS i band at the South Celestial Pole, which contains the diffused Galactic light of about 0.06 mag. There are no thick clouds in the year of 2008. Relatively strong aurorae are detected by their brightening the normal sky, which contribute up to about 2 of the observed images.