Hipparcos: First results of the photometric processing

Abstract

The analysis of the photon counts collected by the ESA HIPPARCOS satellite allows to determine for each program star a magnitude in the H-filter. We present the general principles of the data reduction restricted to the photometry. It is shown that photometric recognition of close binary stars, down to 100 arcsec separation is an attainable goal, along with variability measurements with an accuracy of 0.005 mag for an eight magnitude star. Results on sample data streams show that both accuracy and precision exceed in quality the pre-launch expectations.