Scan around the field of view to stop your brain from mistaking dim targets as ‘noise’
WHEN YOUR FULLY dark-adapted eyes are working in very low light you will probably notice lots of random flashes, sparkles and other general background noise. If you then stare fixedly through the eyepiece, even using averted vision, any low-contrast object will fade from view. This is because the eye and brain will just treat the object as part of this background noise. Scan your eye around the field, however, and you stand a much better chance spotting your target. When the retina is exposed to a dim, low-contrast pattern that is moving, the brain recognises it as something real rather than background noise.
To detect a faint galaxy somewhere in the eyepiece, allow your eye to naturally scan around the field of view at random. As well as creating some movement of the object on the retina, the image will occasionally land on the retina’s more light-sensitive peripheral parts, making the galaxy briefly visible.
Even with the eye scanning around the field, the brain tends to ignore spread-out areas with a low-contrast gradient. If these areas are moved relative to the darker edges of the eyepiece field, however, they then become much easier to see. Try using small back and forth movements of the telescope or repeatedly tap the side of the eyepiece and see the difference it makes.
If scanning the eye around the field doesn’t help, try tiny movements of the telescope