Question

Why does the objective of an optical telescope have large focal length and large aperture? Also explain why does a telescope give better image of a small portion of the celestial body?

Answer 1

The telescope wants to gather more light to show unconscious objects. Therefore the purpose lens or mirror is always bigger.The telescope does 3 things

1. Collect more light than your eyes.

2. They solve the closest objects.

3. They grow Work 1 and 2 depending on the size of the objective.