Sorry I thought you were talking about hunting scopes , my mistake. I never liked a spotting scope very well , but the newer ones with larger eye pieces and objective lenses are pretty nice. I like binoculars I have 20 X 80 Steiner, 10 X 80 what they call tank glasses , and a pair of CELESTRON 25 X 100 they all have an exit pupil of 4 or better. The larger the exit pupil number the better the glass is in dim light situations. To determine the exit pupil divide the magnification into the objective, in the case of a spotting scope set at 20 power and an objective lens of 80mm exit pupil is - 4 if the objective lens was 100mm it would be 5 , that would be real good. The 10 X 80 glasses have an exit pupil of 8 , that's one of the reasons they are so good. The coatings mean a lot also as far as brightness. Good hunting and be safe.