Off-center viewing

Looking slightly to the side of an object to use the light-sensitive rods at night.

As taught in When Your Senses Lie: Disorientation, Motion Sickness, Ears and Night Vision (Aeromedical Factors) — a free lesson with cited FAA sources.

Looking slightly to the side of an object so its image falls on the rods.

As taught in How the Eye Sees at Night (Night Operations) — a free lesson with cited FAA sources.