Andrea Baruffolo, Leopoldo Benacchio, Lucio Benfante (Osservatorio Astronomico di Padova)
The second Guide Star Catalog (GSC II) will be the successor of the first astrometric and photometric catalog built to support the operations of the Hubble Space Telescope. It will be a catalog of positions, proper motions, magnitudes and colors for stars and galaxies complete down to V=18.5 and is expected to be completed by the end of 1999. Besides its operational nature and thanks to its performances and all-sky coverage, the GSC II will be a powerful tool for galactic and extragalactic research. Due to its collaboration to the GSC II project, the Italian astronomical community will be provided with a copy of the catalog as soon as it will be completed. With an expected number of records of the order of two billions, this catalog will pose problems for an efficient access to the data. In this paper we describe our on going effort aimed at building a management system for the GSC II, based on a new technology Object Relational Database Management System, that will allow researchers to fully exploit the scientific content of this catalog. We thus give an overview of the architecture of the system, of the data model being developed, of the extensions we are making to the database engine to support astronomical data, and of the access interfaces currently under development.