Perceived Daylight and Horizon Color on the Moon: Contrast, Exosphere, and Δf Geometry

This note examines why lunar daytime would appear bright to human observers despite the absence of an atmosphere. Using contrast geometry, sensor limitations, regolith optics, and the Moon’s collisionless exosphere, the work explains why no true sky color forms while allowing a physically constrained, narrow-band horizon glow. The analysis remains consistent with mainstream optics and introduces testable predictions for upcoming lunar missions.