How can I find out my naked-eye magnitude limit?
Count stars inside the Great Square of Pegasus, which is well placed on November evenings. If you can see only two stars within the square, you are reaching visual magnitude 4.6 and your skies are probably light polluted. If you spot eight stars you are hitting magnitude 5.5,and 13 stars 6.0. A tally of 31 to 37 stars on a dark, moonless night means an exceptionally good naked-eye limit of 6.5. At Athens Observatory in the mid-19th century, Julius Schmidt counted 102 stars; he was seeing down to magnitude 7.4!
— Roger W.Sinnott