Name

---

      FTAB_HELP

Purpose

---

      Describe the columns of a FITS binary or ASCII table extension(s).

Calling Sequence

---

      FTAB_HELP, filename, [ EXTEN_No = , TEXTOUT= ]
              or
      FTAB_HELP, fcb, [EXTEN_No=, TEXTOUT= ]

Inputs

---

      filename - scalar string giving name of the FITS file.
      fcb - FITS control block returned by a previous call to FITS_OPEN

Optional Keyword Inputs

---

      EXTEN_NO - integer scalar or vector specifying which FITS extensions
              to display. Default is to display all FITS extension.
      TEXTOUT - scalar number (0-7) or string (file name) determining
              output device (see TEXTOPEN). Default is TEXTOUT=1, output
              to the user's terminal

Example

---

      Describe the columns in the second and fourth extensions of a FITS
      file spec.fits and write the results to a file 'spec24.lis'
      IDL> ftab_help,'spec.fits',exten=[2,4],t='spec24.lis'

System Variables

---

        Uses the non-standard system variables !TEXTOUT and !TEXTUNIT
      which must be defined (e.g. with ASTROLIB) before compilation

Notes

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      The behavior of FTAB_HELP was changed in August 2005 to display
      all extensions by default, rather than just the first extension

Procedures Used

---

      FITS_READ, FITS_CLOSE, FITS_OPEN, FTHELP, TBHELP, TEXTOPEN, TEXTCLOSE

History

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      version 1 W. Landsman August 1997
      Corrected documentation W. Landsman September 1997
      Don't call fits_close if fcb supplied W. Landsman May 2001
      Default now is to display all extensions, EXTEN keyword can now
        be a vector W. Landsman Aug 2005