Daytime Sky Brightness at Dome C, Antarctica: Results from All ESCAPE Campaigns

Year: 2024

Authors: Haudemand H., Capobianco G., Fineschi S., Liberatore A., Del Guasta M.

Autors Affiliation: INAF Natl Inst Astrophys, OATo Astrophys Observ Turin, Via Osservatorio 20, I-10025 Pino Torinese, To, Italy; Univ Turin, Phys Dept, Via Pietro Giuria 1, I-100125 Turin, Italy; CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA; Ist Nazl Ott CNR, Via Nello Carrara 1, Sesto Fiorentino, Italy.

Abstract: The study of the solar corona is a prominent focus in the field of solar physics. However, conducting ground-based observations of the corona is a challenging task due to the interference caused by the diffused sky brightness, which obscures the faint coronal signal. As a result, such observations are primarily carried out during total solar eclipses. The requirement of a sky-brightness level as low as times the solar disk brightness () is met by few places on Earth, and currently there are only two sites hosting solar observatories that satisfy this criterion, Mauna Loa and Haleakala, both located in Hawaii. Nevertheless, another candidate coronagraphic site was discovered in the Concordia Station at Dome C plateau, Antarctica ( m a.s.l.). In this article, we show the last results of the Extreme Solar Coronagraphy Antarctic Program Experiment (ESCAPE) during the 38th summer campaign of the Italian Piano Nazionale di Ricerche in Antartide (PNRA). Here, we report a model for estimating the air column, which allows for the first time to account for variations in the Sun’s altitude above the horizon during different observation periods, and we use it to compare the obtained results with previous campaigns. Our results confirm that Dome C is an ideal coronagraphic site with the required sky-brightness level, reaching in optimal conditions.

Journal/Review: SOLAR PHYSICS

Volume: 299 (10)      Pages from: 145-1  to: 145-22

More Information: This paper has been possible thanks to the whole INAF and ESCAPE Project team and the Italian Piano Nazionale Ricerche Antartico (PNRA 2022). The AntarctiCor-ESCAPE project is funded by the PNRA, grant N. 2015-AC3.02. The work of A.L. was partially conducted at the Jet Propulsion Laboratory, California Institute of Technology under a contract from NASA (80NM0018D0004). A particular acknowledgment to OPTEC S.p.A for the AntarctiCor telescope thermal and structural design and realization as well. The authors thank also ALTEC Company for providing logistic support during the many AntarctiCor calibration periods at the INAF OPSys facility. PROBA-3/ASPIICS is an ESA mission.
KeyWords: Sky brightness; Solar corona; Antarctica; Dome C; Polarization; Earth´s atmosphere; Instrumental effects; Airmass; Micropolarizer camera; Astronomical site characterization
DOI: 10.1007/s11207-024-02387-8