The albedo of the earth and its atmosphere defines the diffuse background radiation field for a view from a satellite. Very intense absorption in the diffuse Hartley bands of ozone and weaker absorption in the continuum of the O2 Herzberg bands reduce this albedo to a minimum in the middle ultraviolet spectral region between 2000 and 2950 angstroms. The absorption is so strong that the contributions by multiple scattering of photons can be neglected completely in computing the albedo for this spectral region. Thermal radiation from the atmosphere also makes no contribution in the ultraviolet. (Author).