A Very Special Catalogue: The Hipparcos Input Catalogue

Abstract

The various characteristics of the HIPPARCOS Input Catalogue are described:–How to select 110 000 stars for HIPPARCOS observation from the 210 000 proposed stars, taking into account the following sometimes conflicting requirements : satisfy a maximum of scientific programmes and respect the observational constraints inherent in the HIPPARCOS satellite operation ?–What are the present results regarding the principal astrometric programmes ?–How to process the specific problems which are raised by the HIPPARCOS observation of double and multiple stars and of stars in dense areas ?–Which compilations and observations have been undertaken and are in progress within the frame of the Input Catalogue preparation ? What will be the quality of the final data ?Finally, the contents of the catalogues and annexes that will be published are briefly presented.