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# fk52h

erfa.fk52h(r5, d5, dr5, dd5, px5, rv5)

  Transform FK5 (J2000.0) star data into the Hipparcos system.

  Parameters
    r5 double array
    d5 double array
    dr5 double array
    dd5 double array
    px5 double array
    rv5 double array
  Returns
    rh double array
    dh double array
    drh double array
    ddh double array
    pxh double array
    rvh double array

  Notes

  Wraps ERFA function `eraFk52h`. The ERFA documentation is:

      - - - - - - - - -
       e r a F k 5 2 h
      - - - - - - - - -

      Transform FK5 (J2000.0) star data into the Hipparcos system.

      Given (all FK5, equinox J2000.0, epoch J2000.0):
         r5      double    RA (radians)
         d5      double    Dec (radians)
         dr5     double    proper motion in RA (dRA/dt, rad/Jyear)
         dd5     double    proper motion in Dec (dDec/dt, rad/Jyear)
         px5     double    parallax (arcsec)
         rv5     double    radial velocity (km/s, positive = receding)

      Returned (all Hipparcos, epoch J2000.0):
         rh      double    RA (radians)
         dh      double    Dec (radians)
         drh     double    proper motion in RA (dRA/dt, rad/Jyear)
         ddh     double    proper motion in Dec (dDec/dt, rad/Jyear)
         pxh     double    parallax (arcsec)
         rvh     double    radial velocity (km/s, positive = receding)

      Notes:

      1) This function transforms FK5 star positions and proper motions
         into the system of the Hipparcos catalog.

      2) The proper motions in RA are dRA/dt rather than
         cos(Dec)*dRA/dt, and are per year rather than per century.

      3) The FK5 to Hipparcos transformation is modeled as a pure
         rotation and spin;  zonal errors in the FK5 catalog are not
         taken into account.

      4) See also eraH2fk5, eraFk5hz, eraHfk5z.

      Called:
         eraStarpv    star catalog data to space motion pv-vector
         eraFk5hip    FK5 to Hipparcos rotation and spin
         eraRxp       product of r-matrix and p-vector
         eraPxp       vector product of two p-vectors
         eraPpp       p-vector plus p-vector
         eraPvstar    space motion pv-vector to star catalog data

      Reference:

         F.Mignard & M.Froeschle, Astron.Astrophys., 354, 732-739 (2000).

      This revision:  2021 May 11

      Copyright (C) 2013-2021, NumFOCUS Foundation.
      Derived, with permission, from the SOFA library.  See notes at end of file.