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An all-sky astrometric and photometric catalog prepared for the operation of the Hubble Space Telescope. (Copyright, 1989, Association of Universities for Research in Astronomy, Inc.). This set of CD-ROMs contains the Guide Star Catalog - Version 1, with an issue date of 1 June 1989. The Guide Star Catalog (GSC) was prepared by the Space Telescope Science Institute (ST ScI), 3700 San Martin Drive, Baltimore, MD 21218, USA. ST ScI is operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under contract with the National Aeronautics and Space Administration (NASA).

The Guide Star Catalog is subdivided into regions, which are bounded by small circles of right ascension and great circles of declination, and which are numbered consecutively from 0001 to 9537. Data for each region are stored as separate files; these files are contained in subdirectories, each of which subtends a 7.5 degree zone of declination.

The Guide Star Catalog is distributed as a two CD-ROM set, divided at a declination of -7.5 degrees. This description file and supporting tables are duplicated on both discs. All data files (i.e., with the exception of this file and the directory files) are in FITS (Flexible Image Transport System) table format.

The root directory contains the following files:

  • README.TXT;1 This file.
  • GSC Directory for GSC region files.
  • TABLES Directory for GSC supporting tables.

Directory GSC contains subdirectories for the 7.5 degree zones in declination; these subdirectories in turn contain the GSC region files in FITS format for the respective zone, with file identifiers of the form nnnn.GSC;1, where nnnn is the 4-digit decimal region number, with leading zeroes used as required to fill the field. The subdirectories are named as follows:

Subdirectory Declination Regions Disc From To From To
N0000 +00d 00m +07d 30m 0001 0593 1
N0730 +07d 30m +15d 00m 0594 1177 1
N1500 +15d 00m +22d 30m 1178 1728 1
N2230 +22d 30m +30d 00m 1729 2258 1
N3000 +30d 00m +37d 30m 2259 2780 1
N3730 +37d 30m +45d 00m 2781 3245 1
N4500 +45d 00m +52d 30m 3246 3651 1
N5230 +52d 30m +60d 00m 3652 4013 1
N6000 +60d 00m +67d 30m 4014 4293 1
N6730 +67d 30m +75d 00m 4294 4491 1
N7500 +75d 00m +82d 30m 4492 4614 1
N8230 +82d 30m +90d 00m 4615 4662 1
S0000 -00d 00m -07d 30m 4663 5259 1
S0730 -07d 30m -15d 00m 5260 5837 2
S1500 -15d 00m -22d 30m 5838 6411 2
S2230 -22d 30m -30d 00m 6412 6988 2
S3000 -30d 00m -37d 30m 6989 7522 2
S3730 -37d 30m -45d 00m 7523 8021 2
S4500 -45d 00m -52d 30m 8022 8463 2
S5230 -52d 30m -60d 00m 8464 8839 2
S6000 -60d 00m -67d 30m 8840 9133 2
S6730 -67d 30m -75d 00m 9134 9345 2
S7500 -75d 00m -82d 30m 9346 9489 2
S8230 -82d 30m -90d 00m 9490 9537 2

Directory TABLES contains the following supporting files for the GSC, written in FITS table format:

COMMENTS.TBL;1 - Introduction and general comments.
PLATES.TBL;1 - Information on the plates used in the GSC.
PROCESS.TBL;1 - Image processing parameters.
ASTR_CAL.TBL;1 - Parameters of astrometric calibrations.
PHOT_CAL.TBL;1 - Parameters of photometric calibrations.
C_UP_POP.TBL;1 - Catalog update population statistics.
ST_POP.TBL;1 - Population statistics for stars.
NS_POP.TBL;1 - Population statistics for non-stars.
REGIONS.TBL;1 - Boundaries of GSC regions.
C_RE_POP.TBL;1 - GSC region population statistics.
LG_REG_X.TBL;1 - Index to large regions.
SM_REG_X.TBL;1 - Index to small regions.
XREF_P2R.TBL;1 - Cross-reference table, plates to regions.
XREF_R2P.TBL;1 - Cross-reference table, regions to plates.

Additional information on the Guide Star Catalog may be found in accompanying scientific publications and in comments in the FITS headers of the supporting tables.

Last Updated Jan 2001
Copyright 1989-2001 The Association of Universities for Research in Astronomy, Inc. All Rights Reserved.

Last Modified: 2006-04-06 21:04