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Diffstat (limited to 'ast/erfa/h2fk5.c')
| -rw-r--r-- | ast/erfa/h2fk5.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/ast/erfa/h2fk5.c b/ast/erfa/h2fk5.c new file mode 100644 index 0000000..ad7e9a6 --- /dev/null +++ b/ast/erfa/h2fk5.c @@ -0,0 +1,157 @@ +#include "erfa.h" + +void eraH2fk5(double rh, double dh, + double drh, double ddh, double pxh, double rvh, + double *r5, double *d5, + double *dr5, double *dd5, double *px5, double *rv5) +/* +** - - - - - - - - - +** e r a H 2 f k 5 +** - - - - - - - - - +** +** Transform Hipparcos star data into the FK5 (J2000.0) system. +** +** Given (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) +** +** Returned (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) +** +** Notes: +** +** 1) This function transforms Hipparcos star positions and proper +** motions into FK5 J2000.0. +** +** 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 eraFk52h, eraFk5hz, eraHfk5z. +** +** Called: +** eraStarpv star catalog data to space motion pv-vector +** eraFk5hip FK5 to Hipparcos rotation and spin +** eraRv2m r-vector to r-matrix +** eraRxp product of r-matrix and p-vector +** eraTrxp product of transpose of r-matrix and p-vector +** eraPxp vector product of two p-vectors +** eraPmp p-vector minus p-vector +** eraPvstar space motion pv-vector to star catalog data +** +** Reference: +** +** F.Mignard & M.Froeschle, Astron. Astrophys. 354, 732-739 (2000). +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** Derived, with permission, from the SOFA library. See notes at end of file. +*/ +{ + int i; + double pvh[2][3], r5h[3][3], s5h[3], sh[3], wxp[3], vv[3], pv5[2][3]; + + +/* Hipparcos barycentric position/velocity pv-vector (normalized). */ + eraStarpv(rh, dh, drh, ddh, pxh, rvh, pvh); + +/* FK5 to Hipparcos orientation matrix and spin vector. */ + eraFk5hip(r5h, s5h); + +/* Make spin units per day instead of per year. */ + for ( i = 0; i < 3; s5h[i++] /= 365.25 ); + +/* Orient the spin into the Hipparcos system. */ + eraRxp(r5h, s5h, sh); + +/* De-orient the Hipparcos position into the FK5 system. */ + eraTrxp(r5h, pvh[0], pv5[0]); + +/* Apply spin to the position giving an extra space motion component. */ + eraPxp(pvh[0], sh, wxp); + +/* Subtract this component from the Hipparcos space motion. */ + eraPmp(pvh[1], wxp, vv); + +/* De-orient the Hipparcos space motion into the FK5 system. */ + eraTrxp(r5h, vv, pv5[1]); + +/* FK5 pv-vector to spherical. */ + eraPvstar(pv5, r5, d5, dr5, dd5, px5, rv5); + + return; + +} +/*---------------------------------------------------------------------- +** +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** All rights reserved. +** +** This library is derived, with permission, from the International +** Astronomical Union's "Standards of Fundamental Astronomy" library, +** available from http://www.iausofa.org. +** +** The ERFA version is intended to retain identical functionality to +** the SOFA library, but made distinct through different function and +** file names, as set out in the SOFA license conditions. The SOFA +** original has a role as a reference standard for the IAU and IERS, +** and consequently redistribution is permitted only in its unaltered +** state. The ERFA version is not subject to this restriction and +** therefore can be included in distributions which do not support the +** concept of "read only" software. +** +** Although the intent is to replicate the SOFA API (other than +** replacement of prefix names) and results (with the exception of +** bugs; any that are discovered will be fixed), SOFA is not +** responsible for any errors found in this version of the library. +** +** If you wish to acknowledge the SOFA heritage, please acknowledge +** that you are using a library derived from SOFA, rather than SOFA +** itself. +** +** +** TERMS AND CONDITIONS +** +** Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions +** are met: +** +** 1 Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** +** 2 Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** +** 3 Neither the name of the Standards Of Fundamental Astronomy Board, +** the International Astronomical Union nor the names of its +** contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +** POSSIBILITY OF SUCH DAMAGE. +** +*/ |