I think the main useful thing about 7x50 is that 50mm (diameter of the input lens) divided by 7 (magnification) is just over 7mm, which would be the diameter of the image in the output lens and is also approximately the maximum diameter of your pupil, meaning that the field of view is never smaller than your pupil and you can always see properly. If the exit diameter is smaller than your pupil then it is like you are peering through a small hole.

If you know you are going to be viewing in bright daylight then your pupils will be smaller and you can use smaller lenses like 7x35 or so or for extra magnification you could use 10x40 but with higher magnification you get more jitter anyway.

In low light conditions, if you compare the field of view through some 7x50's vs straight gazing, you will notice that the scene seems brighter as well as closer. That is because you are receiving light from 50mm dia onto your retina vs light from 7mm diameter.

and thats enough about optics, back to the space rockets.