An astronomical telescope has a large aperture to

The correct answer is Option (2) → have high resolution

The resolving power of a telescope increases with the diameter \( D \) of its objective, because the smallest angle between two objects that can still be seen as separate is

    \( \displaystyle \Delta\theta \approx \frac{1.22\,\lambda}{D} \)

A large aperture also gathers more light, so faint objects can be seen, but the property named among the options is the high resolution.

Option (2) have high resolution — Correct. A larger \( D \) makes \( \Delta\theta \) smaller, so close objects are seen distinctly.

NCERT (2026-27):
Telescope – “… The main considerations with an astronomical telescope are its light gathering power and its resolution or resolving power. … The resolving power, or the ability to observe two objects distinctly, which are in very nearly the same direction, also depends on the diameter of the objective. So, the desirable aim in optical telescopes is to make them with objective of large diameter.”