The answer is The telescope collects light over a larger area. You can see fainter stars with an 8-inch telescope than you can see with your naked eye because the telescope collects light over a larger area.
You can see fainter stars with an 8-inch telescope than you can see with your naked eye because the telescope has a much larger object glass compared to the 'pupil' of the eye.
Explanation:
A telescope, a microscope, or a simple magnifying glass act like just another extension added to the naked eye that amplify the light falling on them.
The pupil of a naked eye only allows the 'light to pass' through a small hole to fall on the retina.
The surface area of the pupil is way too small than the surface area of the object glass of a telescope.
The object glass of the telescope simplygathers 'more light' than the pupil can and beams it back to the eye.
Thus, fainter objects in the sky that cannot be seen with naked eyes can easily be seen through a telescope.
