.help hfk5z Jun99 "Slalib Package"
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      SUBROUTINE slHF5Z (RH,DH,EPOCH,R5,D5,DR5,DD5)

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      H F 5 Z
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  Transform a Hipparcos star position into FK5 J2000, assuming
  zero Hipparcos proper motion.

  (double precision)

  Given:
     RH        d      Hipparcos RA (radians)
     DH        d      Hipparcos Dec (radians)
     EPOCH     d      Julian epoch (TDB)

  Returned (all FK5, equinox J2000, epoch EPOCH):
     R5        d      RA (radians)
     D5        d      Dec (radians)

  Called:  slDS2C, slDAVM, slDMXV, slDAVM, slDMXM,
           slDIMV, slDVXV, slDC6S

  Notes:

  1)  The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt.

  2)  The FK5 to Hipparcos transformation consists of a pure
      rotation and spin;  zonal errors in the FK5 catalogue are
      not taken into account.

  3)  The published orientation and spin components are interpreted
      as "axial vectors".  An axial vector points at the pole of the
      rotation and its length is the amount of rotation in radians.

  4)  It was the intention that Hipparcos should be a close
      approximation to an inertial frame, so that distant objects
      have zero proper motion;  such objects have (in general)
      non-zero proper motion in FK5, and this routine returns those
      fictitious proper motions.

  5)  The position returned by this routine is in the FK5 J2000
      reference frame but at Julian epoch EPOCH.

  6)  See also slFK5H, slHFK5, slF5HZ.

  Reference:

     M.Feissel & F.Mignard, Astron. Astrophys. 331, L33-L36 (1998).

  P.T.Wallace   Starlink   7 October 1998

  Copyright (C) 1998 Rutherford Appleton Laboratory
  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.

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