The UIT Survey of the Ultraviolet Sky Background

Abstract

When viewed from above the Earth's atmosphere, the nighttime ultraviolet sky background is profoundly dark - up to 100 times fainter than the equivalent visible background as measured by groundbased telescopes. Because the UV background is so faint, its measured strength and spatial distribution remain controversial topics. Estimates range from a few hundred photons/(sec cm^2 sr^2 A) (~27 mag/arcsec^2) with no obvious spatial distribution to several thousand ``photon units'' with a strong gradient toward the Galactic midplane. Herein, we summarize recent results from an analysis of UV images obtained by the Ultraviolet Imaging Telescope - where relatively high nighttime UV intensities are found near the Galactic midplane which then diminish to levels of ~300 photon units or less at high Galactic latitude.