Direct Orbit Sky

From the Latin directus, straight — used as a color modifier since the eighteenth century for hues that read as straightforward and unambiguous. Direct red, direct green: moderate-to-high saturation combined with optical clarity. Sits at the crisp-bucket center alongside clear and frank.

Latin orbita, track-or-wheel-rut. As a color modifier, orbit implies a Keplerian-ellipse-and-circling quality, the visual register of Keplerian-ellipse-and-Newton-Principia-orbit hand-Keplerian-ellipse-and-circling Keplerian-ellipse-and-Newton-Principia-and-Tycho-orbit orbit-and-Keplerian-ellipse-and-circling surfaces under Keplerian-ellipse-and-Newton-Principia-and-Tycho-orbit Royal-Society-and-celestial-mechanics 17th-century-observation-light. Sits at the modifier-and-cosmic end of the grid, parallel to axis and parsec 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.