We should have something orbiting Neptune or at least on its way. I’ll be a very old man before anything could get there if we want to put something orbit (if I’m not already gone by then).
I wonder how dark it would be out there if you saw it with your own eyes. I would guess it’s pretty dark.
Moonlight is 250000x dimmer than sunlight, but you can still see things illuminated by moonlight once your eyes adjust.
Neptune is 29 AU from the Sun, so by inverse square law, the sunlight is 29^2=840x dimmer on Neptune than Earth. Visibility should be decent out there. Neptune will stand out pretty well against the perfect blackness of space.
Eyes dynamic range is good enough that the "background" isn't black either, consider the view of the night sky from outside a city.
I don't actually know though.
Think you got your nouns mixed up there ;)