Ostentatious Nebula Sky

Latin ostentātiōnis, display — adjectival suffix -ous, derived from ostendere (to show). As a color modifier, ostentatious implies a saturated-and-attention-demanding-and-elaborate quality, the bright color of Belle-Époque-and-Gilded-Age showy-luxury-display interior-decoration. Sits at the bright-and-flamboyant end of the grid, parallel to flamboyant and showy in usage.

Latin nebula, mist-or-cloud. As a color modifier, nebula implies a glowing-cloud-and-stellar-cradle quality, the visual register of Orion-and-Eagle-Nebula hand-glowing-cloud-and-stellar-cradle Orion-and-Eagle-and-Crab-Nebula nebula-and-glowing-cloud-and-stellar-cradle surfaces under Orion-and-Eagle-and-Crab-Nebula Hubble-and-James-Webb-deep-field stellar-cradle-light. Sits at the modifier-and-cosmic end of the grid, parallel to plasma and meteor 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.