Concave mirrors are used in reflecting telescopes, catadioptric lens systems, headlamps, automobile headlights, solar cookers, shaving/cosmetic mirrors, and spotlights (like the bat signal)

Concave mirrors are used in reflecting telescopes, catadioptric lens systems, headlamps, automobile headlights, solar cookers, shaving/cosmetic mirrors, and spotlights (like the bat signal).

In general there are three principle uses for concave mirrors:

1)to collect light from a large area into a small area (as in a telescope)

2)to gather light from a point-like source and direct it outward in a beam (as with a headlamp, or spotlight)

3)to form an enlarged image when held close up (as in the case of a shaving mirror, a cosmetic mirror in a compact, or the small mirror that dentists and dental hygienists use to examine teeth).

Although it doesn't look like it, a satellite TV dish is a concave mirror that reflects light in the microwave range of wavelengths.