As totality or very deep annularity arrives, the pearly–white solar atmosphere flashes into view surrounding the new moon’s darkened disk. Known by such colourful names as “halo” and “glory” from earliest times, this is the corona, a tenuous region of free electrons and interplanetary dust extending millions of kilometres into space and shining in the eclipse sky with the intensity of the full moon.
The inner or K–corona, composed largely of electrons, displays a continuous spectrum and provides a backdrop for viewing prominences. The outer dust or F–corona has an absorption spectrum, extends for several solar diameters, varies in shape from eclipse to eclipse but is generally irregular, and features spectacular radial streamers.
The sun’s corona varies from a generally uniform and circular appearance around times of sunspot maximum to a highly irregular one near sunspot minimum.