Py ERFA:docs

- Index
- Modules

### Navigation

- next »
- « previous |
- PyERFA v2.0.1.5 »
- erfa Package »
- fk5hip

# fk5hip

erfa.fk5hip()

  FK5 to Hipparcos rotation and spin.

  Returns:
    r5h double array
    s5h double array

  Notes

  Wraps ERFA function `eraFk5hip`. The ERFA documentation is:

      - - - - - - - - - -
       e r a F k 5 h i p
      - - - - - - - - - -

      FK5 to Hipparcos rotation and spin.

      Returned:
         r5h   double[3][3]  r-matrix: FK5 rotation wrt Hipparcos (Note 2)
         s5h   double[3]     r-vector: FK5 spin wrt Hipparcos (Note 3)

      Notes:

      1) This function models the FK5 to Hipparcos transformation as a
         pure rotation and spin;  zonal errors in the FK5 catalog are not
         taken into account.

      2) The r-matrix r5h operates in the sense:

               P_Hipparcos = r5h x P_FK5

         where P_FK5 is a p-vector in the FK5 frame, and P_Hipparcos is
         the equivalent Hipparcos p-vector.

      3) The r-vector s5h represents the time derivative of the FK5 to
         Hipparcos rotation.  The units are radians per year (Julian,
         TDB).

      Called:
         eraRv2m      r-vector to r-matrix

      Reference:

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

      This revision:  2023 March 6

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