What are the faintest stars visible to the naked eye?

Answer 1

Depending on your eyesight (everyones' is different) and the amount of air pollution and light pollution, people with "good" eyesight and in a clear, DARK area can generally just barely see a seventh-magnitude star.

Look at the Big Dipper, if you live in the northern hemisphere. People usually look at the Big Dipper and follow the "pointer" stars Merak and Dubhe straight out to the north star, Polaris. But I want you to look at the handle of the dipper, the middle star in the handle. The middle star is Mizar, and it is magnitude 2.2; not especially bright, but most everybody can see it. But look closely; is that ONE star, or are there two?

There are two; the dimmer star is Alcor, and it is just above 4th magnitude. Julius Caesar's Legions used that star as an eye test; if you could see Alcor, then your vision was good enough to be an archer; otherwise, you were a swordsman.

Answer 2

The faintest stars visible to the naked eye have an apparent magnitude of about +6.5 in ideal conditions, away from light pollution. These stars are at the limit of human visibility without the aid of telescopes or binoculars.