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Discussion of Example 3 (A Galaxy Catalog in an ASCII Table)

This pair of headers illustrates the case where all the data are in an extension. Like Example 2, it is from the NRAO ftp collection. It is a catalog of galaxies, probably of parent galaxies of supernovae (OBJECT keyword) originating at the European Southern Observatory (ORIGIN keyword and comments). It was created on 27 May 1984 (DATE keyword) and thus may not show how ESO-MIDAS would now write an ASCII table, but it can still illustrate the format. The primary header carries two additional pieces of information: that there is no primary data array (value of zero for NAXIS keyword) and that an extension may be present (T value for EXTEND keyword). The comment following the EXTEND keyword notes that an extension is present. The END card image is followed by 28 card images consisting of ASCII blanks, to fill the record to 2880 bytes. The string XTENSION= 'TABLE   ' at the start of the next record introduces the header of an ASCII table extension. The BITPIX, NAXIS, PCOUNT, and GCOUNT keywords have the values required for an ASCII table. The NAXISn keywords show that it is ten rows long with 98 characters per row. Each row consists of seven fields (TFIELDS keyword), all in FORTRAN format E14.7 (TFORMn keywords), with no blanks between (TBCOLn keywords). A null value in any field is represented by a blank (TNULLn keywords). The seven fields in each row represent a galaxy identifier, right ascension, declination, type, diameter of the galaxy at the 25 mag/arcsec level, inclination, and radial velocity, respectively (TTYPEn keywords).


next up previous contents
Next: Example 4:  Binary Table Up: Examples of FITS Headers Previous: Example 3:  ASCII Table