Detection of polarization neutral points in observations of the combined corona and sky during the 21 August 2017 total solar eclipse

TL;DR

This study employs synchronized DSLR cameras with polarization filters to observe and identify polarization neutral points in the corona and sky during the 2017 total solar eclipse, enhancing understanding of solar corona polarization.

Contribution

It introduces a novel method using synchronized DSLR cameras to detect and analyze polarization neutral points during a solar eclipse.

Findings

Detection of polarization neutral points above and below the Sun

High-dynamic-range RGB polarization imaging of the corona

Confirmation of expected tangential and vertical polarization patterns

Abstract

We report the results of polarimetric observations of the total solar eclipse of 21 August 2017 from Rexburg, Idaho (USA). We use three synchronized DSLR cameras with polarization filters oriented at 0{\deg}, 60{\deg}, and 120{\deg} to provide high-dynamic-range RGB polarization images of the corona and surrounding sky. We measure tangential coronal polarization and vertical sky polarization, both as expected. These observations provide detailed detections of polarization neutral points above and below the eclipsed Sun where the coronal polarization is canceled by the sky polarization. We name these special polarization neutral points after Minnaert and Van de Hulst.