Question

In your initial discussion post, identify the pros and cons of using mirrors versus lenses in each of the following applications:

• a large, ground-based, astronomical telescope
• a small “spy” scope
• a terrestrial telescope designed only to read license plates

Answer 1

Astronomical telescopes
In this case, the mirrors have the advantage that there is no light scattering and the whole image will be formed by a ray of light. In case of lenses there is light scattering and the image formed will be blurred.

Small spy scopes
Mirrors have a disadvantage because the image formation implies a more complex configuration, this is because the image will be formed by reflected rays.
In the case of lenses, it is much simpler since the image is formed by refracted rays and the configuration can be linear.

Terrestrial telescope
In this case, the lenses have the same advantages as the lenses that in the previous case, the image will be formed by refraction.