Continuous 60-Year Observations of the Spectral Solar Corona at the Mountain Astronomical Station of Pulkovo Observatory

Abstract

This paper presents observational series of the spectral solar corona obtained with the Small Lyot Coronagraph deployed in 1948 at the Mountain Astronomical Station of the Central Astronomical Observatory, Russian Academy of Sciences (MAS CAO RAS), near the city of Kislovodsk; this is the only observatory in the world that maintains such large databases (1952–2019) of coronal intensity in the lines λ = 5303 Å (Fe XIV) and λ = 6374 Å (Fe X). Correlation and regression analysis of data from six solar activity cycles has revealed the homogeneity and stability of continuous series of intensities of the green and red corona.