Statement
13.4.20. Why are bright stars visible through a telescope even during the day?
Solution
A telescope has a much larger aperture than the human pupil, so it collects significantly more photons from a star. Additionally, when looking through a telescope, we observe a narrow section of the sky, where less scattered light enters the eye. This reduces the background brightness and increases the contrast between the star and the sky.
Answer
The light flux from the star to the eye increases sharply.