SIMPLE = T / Standard FITS format BITPIX = 8 / Character Information NAXIS = 0 / No image data array present EXTEND = T / Extension exists FILETYPE= 'LG_REG_X' / Indicates file type ORIGIN = 'ST ScI ' / Space Telescope Science Institute DATE = '01/06/89' / Date of issue (dd/mm/yy) COMMENT THE GUIDE STAR CATALOG COMMENT COMMENT An all-sky astrometric and photometric catalog COMMENT prepared for the operation of the Hubble Space COMMENT Telescope. COMMENT COMMENT Copyright, 1989, Association of Universities COMMENT for Research in Astronomy, Inc. COMMENT COMMENT This file contains data for one of the supporting tables for the GuideCOMMENT Star Catalog (GSC). Additional information on the GSC may be found inCOMMENT accompanying scientific publications as well as in comments and tablesCOMMENT elsewhere on this set of volumes. COMMENT COMMENT The Guide Star Catalog (GSC) was prepared by the Space Telescope ScienceCOMMENT Institute (ST ScI), 3700 San Martin Drive, Baltimore, MD 21218, USA.COMMENT ST ScI is operated by the Association of Universities for Research inCOMMENT Astronomy, Inc. (AURA), under contract with the National Aeronautics andCOMMENT Space Administration (NASA). COMMENT COMMENT COMMENT File LG_REG_X COMMENT Index to the Large Regions COMMENT COMMENT The adopted catalog organization divides the sky into large regions,COMMENT approximately 7.5 deg in size, which are then subdivided into smallCOMMENT regions on the basis of their expected individual stellar populations;COMMENT each small region corresponds to one file of the GSC. Some details areCOMMENT given in the comments to file REGIONS; and a full description, includingCOMMENT the region counting rules, may be found in Paper III. COMMENT COMMENT All information needed to associate a point on the sky with a regionCOMMENT file is given in file REGIONS. However, files LR_REG_X, which is anCOMMENT index to the large regions, and SM_REG_X, which is an index to the smallCOMMENT regions, are provided to support a more rapid search algorithm based onCOMMENT the geometric arrangement of the regions and their numbering conven-COMMENT tions. COMMENT COMMENT File LG_REG_X gives, for each declination band DEC_CTR, the number ofCOMMENT the first large region F_LG_REG in the band and the number of largeCOMMENT regions N_LG_REG therein. Similarly, file SM_REG_X gives, for each largeCOMMENT region LG_REG_N, the number F_SM_REG of the first small region and theCOMMENT level of subdivision of the large region DEPTH. Then, for anyCOMMENT coordinate, two simple indexing procedures are sufficient to identifyCOMMENT the large region number and then, obtaining the level to which thatCOMMENT region is subdivided from the small region table, the small regionCOMMENT number which bears a one-to-one correspondence with the name of a GSCCOMMENT file. One need also to note that the first large region in the southernCOMMENT hemisphere is 367. END XTENSION= 'TABLE ' / Table Extension BITPIX = 8 / Character Information NAXIS = 2 / Two-dimensional table NAXIS1 = 15 / Number of characters per line NAXIS2 = 24 / Number of rows PCOUNT = 0 / No Random Parameters GCOUNT = 1 / Only one group TFIELDS = 3 / Three fields per row EXTNAME = 'LG_REG_X' / Large Region Index File EXTVER = 1 / Integer Version Number TTYPE1 = 'DEC_CTR ' / Center of Declination Band TBCOL1 = 1 / Start in column 1 TFORM1 = 'F6.2 ' / Floating, 6 Character Field TTYPE2 = 'N_LG_REG' / Number of Large Regions in Declination Band TBCOL2 = 9 / Start in column 9 TFORM2 = 'I2 ' / Integer, 2 Character Field TTYPE3 = 'F_LG_REG' / ID of first Large Region in Declination Band TBCOL3 = 13 / Start in column 13 TFORM3 = 'I3 ' / Integer, 3 Character Field END
