Hipparcos Input Catalog

The Hipparcos Input Catalogue was constructed as the observing program for the European Space Agency's Hipparcos astrometry mission. The requirements of the project in terms of completeness, sky coverage, astrometric and photometric accuracy, as well as the necessary optimization of the scientific impact, resulted in an extended effort to compile and homogenize existing data, to clarify sources and identifications, and, where needed, to collect new data matching the required accuracy.

This has resulted in an unprecedented catalog of stellar data including up-to-date information of positions, proper motions, magnitudes and colors, and (wherever available) spectral types, radial velocities, multiplicity and variability information. The catalog is complete to well-defined magnitude limits and includes a substantial sampling of the most important stellar categories present in the solar neighborhood beyond these limits.