Night sky brightness at latitude 52°

Abstract

Observations of the night sky brightness at Saskatoon, Canada, latitude 52° 11′N, indicate that the brightness on clear nights without visible polar aurora is appreciably greater than at lower latitudes. Large differences between the average brightnesses for nights without apparent differences in sky and atmospheric conditions, a seasonal variation in the average brightness corresponding approximately to the seasonal occurrence of polar aurora, and observations of sky luminosities when polar aurora is present suggest that this increase in brightness is due to light of polar auroral origin.