Astronomers measure the brightness of stars in magnitudes, which are a strange sort of unit: the brighter a star is, the SMALLER its magnitude.
magnitude 0 stars are very bright: Vega, Arcturus magnitude 2 stars are intermediate: most stars in the Big Dipper magnitude 4 stars are pretty faint: handle of the Little Dipper
How faint can YOU see? Test yourself three ways.
Test 1: The Little Dipper
Can you see all the stars in the handle of the Little Dipper? All the stars in the bowl? Mark the faintest star you can see on the diagram.