%N fitrdhdr %F $MIR/src/subs/fitsio.for
%D Read a real value from a FITS file header.
%P rjs
%: fits
%B
      subroutine fitrdhdr(lu,key,out,default)

      integer lu
      character key*(*)
      real out,default
  ---------------------------------------------------------------------
  Read a real valued FITS card.

  Input:
    lu         File descriptor.
    key        Keyword to be read from header.
    default    Default value if the keyword is not found in the header.

  Output:
    out        Value of the keyword (this will be the default if the
               keyword was not found).
