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Description :

The Guide Star Catalog II (GSC-II) is an all-sky optical catalog based on 1" resolution scans of the photographic Sky Survey plates, at two epochs and three bandpasses, from the Palomar and UK Schmidt telescopes. This all-sky catalog will ultimately contains positions, proper motions, classifications, and magnitudes in multiple bandpasses for almost a billion objects down to approximately Jpg=21, Fpg=20. The GSC-II is currently used for HST Bright Object Protection and HST pointing. Looking ahead, the GSC-II will form the basis of the Guide Star Catalog for JWST. This was constructed in collaboration with ground-based observatories for use with the GEMINI, VLT and GALILEO telescopes

Note - always use the most recent version of GSC 2 (currently 2.3.2) for HST target coordinates!

Versions :

Sky Coverage
Mag limit Bands Ast Phot PM
2.0 January 2000 Science target fields none J,F TYC1 GSPC1 no Ops  
2.1.0 April 2000 30% none J,F TYC1 GSCP1 no consortium  
2.1.1 July 2000 50% none J,F TYC2 GSPC2.1 no consortium  
2.2.0 June 2001 98% F=18.5 J,F TYC2 GSPC2.2 no Public release notes
2.2.1 August 2001 98% none J,F TYC2 GSPC2.2 no Ops  
2.3.0 September 2003 100% none J,F,N TYC2 GSPC2.3 no consortium  
2.3.1 October 2004 100% none J,F,N,+ TYC2 GSPC2.3 yes consortium  
2.3.2 October 2005 100% none J,F,N,+ TYC2 GSPC2.3 yes/no* Ops / Public release notes
2.3.3 October 2009 100% none J,F,N,+ TYC2 GSPC2.3 yes/no* Ops / Public release notes

+ the additional passbands are primarily from the POSSI-E, the POSSI-O and Palomar Quick-V surveys so only cover the northern heimpshere

* the computed proper motions are not yet publically available because we discovered a 10mas/year systematic error for the southern hemisphere that we are still investigating.

References :

The Second Generation Guide Star Catalog : Description and Properties
Lasker et al 2008 AJ 136,735

Properties :

Summary of catalog properties and coded values

Data Access :
GSC 2.0 : not available
GSC 2.1 : not available
GSC 2.2 : superseded by v2.3
GSC 2.3 : on-line | download not supported (200GB)


Last Updated Jan 2001
Copyright 2001 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.

Last Modified: 2007-04-23 10:34