SteveR
You might wish to consider splitting the sky into quadrants at night and scanning all of them, almost mechanically.
This is to ensure that you don't fixate one point and 'lose' something in the blind spot where the optical nerve exits your eye.
This obviously applies in daylight too, but it's easy to get a little 'lazy' at night due to the ease of picking up strobes and other lights which, as you rightly say, do stand out.