A remote pilot is tracking the small UA visually at night. Why does the Pilot's Handbook of Aeronautical Knowledge recommend looking 5° to 10° off-center of the aircraft rather than staring directly at it?

Why: The handbook explains that cones, concentrated at the fovea, are responsible for sharp central vision in daylight but are far less sensitive in low light, while rods — concentrated away from the fovea — handle most night vision. This creates a "night blind spot" at the center of the visual field. Looking 5° to 10° off center shifts the image onto the more light-sensitive rods, making a dim object easier to see at night.

• Autokinesis is caused by staring at a stationary light for a prolonged period, not simply by looking directly at an object instead of off-center — it is a separate illusion from the night blind spot mechanism.
• Empty-field myopia happens when there is nothing specific to focus on, such as above clouds or in haze, not from directly viewing a visible object like the aircraft.