%N coinit %F $MIR/src/subs/co.for
%D Initialise coordinate conversion routines.
%P rjs
%: coordinates
%B
      subroutine coInit(lu)

      integer lu
  ---------------------------------------------------------------------
  Initialise the coordinate conversion system.

  The coordinate conversion routines supports simultaneously a number
  of coordinate systems.  A coordinate system is initialised by a call
  to coInit, giving the handle of the Miriad data-set in question.
  This initialises a new coordinate system.  Subsequent calls to the
  coordinate routines also give the handle of the data-set, which is
  used to determine the appropriate coordinate system to use.

  Input:
    lu         The handle of the Miriad data-set, either an image or
               visibility data-set.  For a visibility data-set, the
               coordinate system simply consists of RA and DEC axes,
               centered on the observing centre.
