An Etymological Dictionary of Astronomy and Astrophysics

The technique of looking slightly to the side of a faint object being studied while continuing to concentrate on the object. The technique helps bring out details which
otherwise would be missed by looking directly at an object. The reason is that the portion of the eye’s retina that best detects dim light (fovea) is located all around the edges rather than the center.

Etymology (EN): Averted p.p. from avert, from O.Fr. avertir, from L. avertere “to turn away,” from → ab- “from, away” + vertere “to turn” (cognate with Pers. gardidan “to turn”); → vision.

Etymology (PE): Negâh, → vision; kaž “averted.”