K-corona recording in the range < 1.4 Rsun

TL;DR

This paper proposes two innovative methods for recording the solar corona within 1.4 solar radii, utilizing advanced thin film technology and eclipse observations to significantly improve measurement sensitivity.

Contribution

It introduces novel coronagraphic techniques with higher transmission and lower background noise, surpassing classical methods for observing the inner solar corona.

Findings

Coronagraphic factor is 100 times higher than Lyot-type.

Instrumental background reduced by at least 1000 times.

New methods enable more effective corona observations near the Sun.

Abstract

Two approaches are suggested for recording the continuum corona in the range < 1.4 Rsun. They are different from the classical coronagraphic ones. Current state in the thin film technology allows discussing a new generation coronagraph with a variable transmission of an entrance aperture. The estimated coronagraphic factor is 2 orders of magnitude higher compared to a Lyot-type coronagraph. Another approach is based on the use of total solar eclipses at near-Mercury orbits. The instrumental background is decreased at least 3 orders of magnitude. That allows using a more simplified optical sketch.