An Etymological Dictionary of Astronomy and Astrophysics

The emission of a part of the night sky that does not contain any detectable objects. Sky background results from
the combined radiation from faint, unresolved stars and other emitting astronomical objects. The mean brightness of night sky background measured at the → Cerro Tololo Inter-American Observatory (CTIO) for the period 1992 to 2006 are:
U = 22.12, B = 22.82, V = 21.79, R = 21.19, and I = 19.85 mag arcsec^-2 ( → rms ~ 0.2 mag arcsec^-2). See also → sky brightness.

See also: → sky; → background..