Clear Corona Sky

From the Latin clarus, bright, distinct — used as a color modifier since the medieval period for hues without haze or mixing. Clear blue sky, clear green water: the implication is moderate saturation combined with optical clarity. Sits at the crisp-bucket center alongside clean and true.

Latin corona, crown-or-circle-of-light. As a color modifier, corona implies a sun-corona-and-eclipse-halo quality, the visual register of total-solar-eclipse-corona hand-sun-corona-and-eclipse-halo total-solar-eclipse-and-Sun-corona-and-Bailey's-Beads corona-and-sun-corona-and-eclipse-halo surfaces under total-solar-eclipse-and-Sun-corona-and-Bailey's-Beads totality-and-Moon-shadow-and-pearl ring-of-fire-light. Sits at the modifier-and-cosmic end of the grid, parallel to prism and nebula in usage.

The blue of a clear sky at noon — produced by Rayleigh scattering, the preferential dispersion of shorter wavelengths through atmospheric molecules. Air itself is colorless; the color we see is sunlight scattered toward our eyes by every cubic kilometer above. The reference shade is mid-latitude noon under a high pressure system: a clean, slightly green-shifted blue with the luminous depth of light scattered across an entire hemisphere of air.