NIGHT-SKY BRIGHTNESS FROM THE VISIBILITY OF STARS NEAR THE HORIZON

Hundreds of naked-eye observations of bright stars near the southern horizon have been made on clear moonless nights over the interval 1977-91. They reveal a consistency in their visibility from one season or year to another, but a deterioration over the entire time interval reveals a possible increase in light pollution and possibly air pollution as well. The method is constrained to the sky near the northern and southern horizons where stars remain at near constant altitude over a suitable time interval, but the repeatability assures that it is sound. The limiting magnitude is given as a function of zenith distance, and color and seasonal effects do not appear to influence the results.