On a clear summer night, look up at the Milky Way. Gigantic clouds of innumerable stars form a stairway to heaven. Grabbing binoculars, the clouds of stairs reveal light and dark streaks, and fuzzy condensations .
Larger apertures reach fainter magnitudes but have narrower fields of view.
The answer hinges on counts of star at particular magnitudes. As you can see, best results come with a 4 inch to a 16 inch aperture used with a magnification of 3.5x per inch of aperture. As many stars visible to the unaided-eyes across the entire sky are visible in a single eyepiece field of view. The 3.5x per inch of aperture is the ratio of the eye's pupil opening in inches to a magnification of 1x. We keep the same ratio for all apertures since this maximizes the light received by the eye.