I had no chance to check how this combination performs at the night sky, and based on the current weather forecast for my area this wont change soonish. However, I used it quite a bit in the past days to read coded colour rings of gulls, and also on an overcast it works well (my locality is within the North Germain Plain ). The contrast is noticeably lower compared to a lower mag eyepiece and the same is obviously true for the brightness, given the small exisit pupil. Most importantly the image is still crispy enough that the high power is usable. Approximately one hour before sunset the limit is reached and there is no gain anymore in using this magnification. On a bright day it will be fine I guess, also for monitoring raptor nests. The main problem I would imagine then, is heat haze.