Definitions for "Averted vision"
viewing an object by looking slightly to its side. This technique can help you detect faint objects that are invisible when you stare directly at them.
A technique of looking slightly to the side of a faint object to increase its visibility through a telescopic eyepiece. By looking slightly off to the side its light falls on the part of the retina most sensitive to light.
An observing trick of looking at an object in the eyepiece is to look a little to one side of the target. This "averted vision" places the target on a more light-sensitive area of the eye's retina where it will pop into view.