The TYCHO star mapper background analysis.

Abstract

The Hipparcos star mapper detector background signal has been analyzed in the Tycho reductions for contributions due to the diffuse galactic light. The methods are presented by which the contributions from the two fields of view of the telescope are separated after elimination of background variations due to the radiation environment (Van Allen belts). A complete sky background map, with a resolution of 0.25 square degrees and based on the data accumulated through almost two years of the mission is presented.