%N cofindax %F $MIR/src/subs/co.for
%D Locate a particular axis in the coordinate system.
%P rjs
%: coordinates
%B
      subroutine coFindAx(lu,axis,iax)

      integer   lu
      character axis*(*)
      integer   iax
  ---------------------------------------------------------------------
  Locate an axis of a particular type.  The type of the axis is given
  by the "axis" parameter.

  Input:
    lu         Handle of the coordinate system.
    axis       This can be either.  Case is unimportant.
               Often this will be a normal FITS-style ctype value, with
               or without the projection/rest-frame part.
               If the projection/rest-frame part is omitted, "axis"
               will match all projections/rest-frames.  For example,
               axis = 'RA' matches 'RA---NCP' and 'RA---SIN' whereas
               axis = 'RA---SIN' only matches 'RA---SIN'.

               It can also be one of:
                 'longitude'  for RA,  GLON and ELON axes.
                 'latitude'   for DEC, GLAT and ELAT axes.
                 'spectral'   for spectral axes.
                 'frequency'  as above, but only if there is enough
                              information to convert to frequency.

  Output:
    iax        The axis index of the desired axis.  A value of 0 is
               returned if the axis is not found.
