A method often used in the visual observation of the night sky, averted vision is the tecnique of looking slightly away from the item you wish to observe.

This works because of the distribution of cones and rods on the retina. The density of cones towards the center of the retina is very high compared to the rest of the retina. As rods are used to distinguish lightness and cones, color, a minor variation in lightness (i.e. a dim star) can be more easily detected slightly off center.