Which statement describes an advantage of reflecting telescopes?

• A. They can be made big and clearer images
• B. They have no need for alignment
• C. They are the lightest and simplest to manufacture
• D. They suffer from chromatic aberration

Answer: (C)

Reflecting telescopes use a curved mirror to collect and focus light, instead of using lenses. This design allows for large apertures without the instrument becoming extremely heavy or expensive, because a mirror can be supported from behind and polished to shape more easily than a thick, wide glass lens. As a result, mirrors enable bigger, lighter, and relatively simpler-to-manufacture telescopes compared with refracting ones. That practical advantage—being able to build large, more affordable optics due to the mirror-based design—is the best description of why reflectors are advantageous. Additionally, mirrors don’t suffer from chromatic aberration, since reflection doesn’t separate light by wavelength, so statements claiming they do have this problem aren’t accurate.