It’s a very big universe out there, and an astronomer’s work is never done when it comes to simply counting and cataloging the sheer number
of stars in the heavens.

Completing a seven-year effort at digitizing and analyzing the entire sky for a second time, astronomers at the Space Telescope Science Institute (STScI) in Baltimore, MD, and the Osservatorio Astronomico di Torino, in Italy,
are releasing the Guide Star Catalog II (GSC-II). This new version, which replaces the historic 1989 catalog, provides important information on nearly one-half billion stars — over 20 times as many as the original Guide Star Catalog.


NOTE TO EDITORS: A photo to accompany this
release is available on the Web at: and via links in; and

The GSC-II consortium is dedicating the catalog to the memory of Dr. Barry M. Lasker, who passed away in February 1999. Dr. Lasker, one of the founders of the STScI, was directly responsible for the vision that led to the creation of the DSS and GSC projects that have greatly influenced and benefited modern observational astronomy.

The Guide Star CatalogñII is a joint project of the Space Telescope Science Institute and the Osservatorio Astronomico di Torino. The
participation of the Osservatorio Astronomico di Torino was supported by the Italian Council for Research in Astronomy. Additional support was provided by the European Southern Observatory, the Space Telescope European Coordinating Facility, the International Gemini project, and the European Space Agency Astrophysics Division.

The Space Telescope Science Institute (STScI) is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), for NASA, under contract with the Goddard Space Flight Center, Greenbelt, MD. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA).

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CONTACT: Brian McLean
Space Telescope Science Institute, Baltimore, MD; Phone: 410-338-4900; E-mail: or Mario G. Lattanzi
Osservatorio Astronomico di Torino Pino Torinese (TO), Italy. Phone: 39-011-8101923; E-mail: