Salyut-4 Observations of Active Regions on the Sun

Abstract

We believe that the examination of the ultraviolet solar spectrum is the most informative tool for the diagnostic of the physical state of the solar plasma. But the well known phenomenon of fine structure of active regions (A.R.), as well as of quiet ones, making spectral lines to be wavy and patchy (across dispersion) demandsa) high spatial resolution on the solar image and b) stigmatic spectra.