#include "erfa.h" void eraBi00(double *dpsibi, double *depsbi, double *dra) /* ** - - - - - - - - ** e r a B i 0 0 ** - - - - - - - - ** ** Frame bias components of IAU 2000 precession-nutation models (part ** of MHB2000 with additions). ** ** Returned: ** dpsibi,depsbi double longitude and obliquity corrections ** dra double the ICRS RA of the J2000.0 mean equinox ** ** Notes: ** ** 1) The frame bias corrections in longitude and obliquity (radians) ** are required in order to correct for the offset between the GCRS ** pole and the mean J2000.0 pole. They define, with respect to the ** GCRS frame, a J2000.0 mean pole that is consistent with the rest ** of the IAU 2000A precession-nutation model. ** ** 2) In addition to the displacement of the pole, the complete ** description of the frame bias requires also an offset in right ** ascension. This is not part of the IAU 2000A model, and is from ** Chapront et al. (2002). It is returned in radians. ** ** 3) This is a supplemented implementation of one aspect of the IAU ** 2000A nutation model, formally adopted by the IAU General ** Assembly in 2000, namely MHB2000 (Mathews et al. 2002). ** ** References: ** ** Chapront, J., Chapront-Touze, M. & Francou, G., Astron. ** Astrophys., 387, 700, 2002. ** ** Mathews, P.M., Herring, T.A., Buffet, B.A., "Modeling of nutation ** and precession New nutation series for nonrigid Earth and ** insights into the Earth's interior", J.Geophys.Res., 107, B4, ** 2002. The MHB2000 code itself was obtained on 9th September 2002 ** from ftp://maia.usno.navy.mil/conv2000/chapter5/IAU2000A. ** ** Copyright (C) 2013-2017, NumFOCUS Foundation. ** Derived, with permission, from the SOFA library. See notes at end of file. */ { /* The frame bias corrections in longitude and obliquity */ const double DPBIAS = -0.041775 * ERFA_DAS2R, DEBIAS = -0.0068192 * ERFA_DAS2R; /* The ICRS RA of the J2000.0 equinox (Chapront et al., 2002) */ const double DRA0 = -0.0146 * ERFA_DAS2R; /* Return the results (which are fixed). */ *dpsibi = DPBIAS; *depsbi = DEBIAS; *dra = DRA0; return; } /*---------------------------------------------------------------------- ** ** ** Copyright (C) 2013-2017, 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. ** */