HIPPARCOS photometry - NDAC reductions

The Hipparcos mission will provide astrometry for about 120,000 stars. It will also give very accurate photometry for these stars. The resulting data base will by far surpass any existing photometric catalog, both in accuracy and number of stars measured. This paper describes the calibrations and initial reductions of the photometry carried out by the Northern Data Analysis Consortium, one of the two data reduction groups analyzing the data.