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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) 2013-2023, NumFOCUS Foundation.
      Derived, with permission, from the SOFA library.  See notes at end of file.