Sky Brightness evaluation at Concordia Station - Dome C, Antarctica for ground-based observations of the Solar Corona

TL;DR

This study measures sky brightness at Dome C, Antarctica, demonstrating extremely low levels suitable for solar corona observations, using specialized instrumentation during Antarctic summer expeditions.

Contribution

First measurement of sky brightness at Dome C with AntarctiCor, showing its potential as a prime site for ground-based solar corona observations.

Findings

Sky brightness at Dome C reaches 0.7 to 1.0 millionth of solar disk brightness.

Optimal conditions yield exceptionally low sky brightness levels.

Results support Dome C as a promising site for solar physics experiments.

Abstract

The evaluation of sky characteristics plays a fundamental role for many astrophysical experiments and ground-based observations. In solar physics, the main requirement for such observations is a very low sky brightness value, that is, less than one-millionth of the solar disk brightness. Few places match such requirement for ground-based, out-of-eclipse coronagraphic measurements. A candidate coronagraphic site is the Dome C plateau in Antarctica. In this paper, we show the first results of the sky brightness measurements at Dome C with the Extreme Solar Coronagraphy Antarctic Program Experiment (ESCAPE) at Italian-French Concordia Station, on Dome C, Antarctica (3300 m) during the summer XXXIV and XXXV Expeditions of the "Italian Piano Nazionale Ricerche Antartiche" (PNRA). The sky brightness measurements were carried out with the internally-occulted Antarctic coronagraph - AntarctiCor. In optimal atmospheric conditions, the sky brightness of Dome C has reached values of the order of 1.0 to 0.7 millionth of of the solar disk brightness.