GSC-II

Telescope Operations Version

GSC 2.2 Public Release

June 2001

The Space Telescope Science Institute and the Osservatorio Astronomico di Torino announce the public release of an all-sky, two bandpass, magnitude-selected subset of the 998,000,000+ unique objects in the GSC-II catalog.

GSC 2.2 contains positions, classifications, and magnitudes for 435,457,355 objects. GSC 2.2 will be used to support telescope operations at the GEMINI and VLT telescopes, and is being released to the public via the WWW. It is based on 1” resolution scans of the photographic sky survey plates from the Palomar and UK Schmidt telescopes in F and J bandpasses (the Digitized Sky Survey - II). The final version of the catalog, GSC2.3, will add proper motions and will include all objects to the limiting magnitude of the Schmidt plates.

			GSC 1.1			GSC 2.2
Total objects			18,819,291			435,457,355
Mean epoch of catalog positions			1981.8			1992.5
Magnitude Limit			15.5			18.5 F, 19.5 J
Complete to magnitude limit			No			Yes
Bandpass: North			V			F and J
Bandpass: South			J			F and J
Scan resolution			1.7 arcsec			1 arcsec
Bright Stars from			Hipparcos Input Catalog			Tycho 2 Catalog
Astrometry:
	Reference Frame			FK4			ICRF
	Reference Catalogs			AGK3, SAO: 10^2calibrators/plate			ACT, Tycho2: 10^3 calibrators/plate
		Errors: Typical			0.5”			0.3”
	Worst case			1.2” (near plate edge)			0.35” – 0.65” (near plate edge for mag>16)
Photometry:
Reference Catalog			GSPC1: 6 standards per plate			GSPC2: 10^2 standards per plate
Errors			0.5 mag			0.2-0.25 mag

Please visit our website for more information: http://www-gsss.stsci.edu

Images and catalog data can also be obtained through MAST:

http://archive.stsci.edu/mast.html

Photo from the press release at http://hubble.stsci.edu/news_.and._views/pr.cgi.2001+18

The Guide Star Catalog–II is a joint project of the Space Telescope Science Institute and the Osservatorio Astronomico di Torino. Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, for the National Aeronautics and Space Administration under contract NAS5-26555. The participation of the Osservatorio Astronomico di Torino is supported by the Italian Council for Research in Astronomy. Additional support is provided by European Southern Observatory, Space Telescope European Coordinating Facility, the International GEMINI project, and the European Space Agency Astrophysics Division.