#include "sofa.h" void iauBi00(double *dpsibi, double *depsbi, double *dra) /* ** - - - - - - - - ** i a u B i 0 0 ** - - - - - - - - ** ** Frame bias components of IAU 2000 precession-nutation models (part ** of MHB2000 with additions). ** ** This function is part of the International Astronomical Union's ** SOFA (Standards Of Fundamental Astronomy) software collection. ** ** Status: canonical model. ** ** 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. ** ** This revision: 2013 June 18 ** ** SOFA release 2019-07-22 ** ** Copyright (C) 2019 IAU SOFA Board. See notes at end. */ { /* The frame bias corrections in longitude and obliquity */ const double DPBIAS = -0.041775 * DAS2R, DEBIAS = -0.0068192 * DAS2R; /* The ICRS RA of the J2000.0 equinox (Chapront et al., 2002) */ const double DRA0 = -0.0146 * DAS2R; /* Return the results (which are fixed). */ *dpsibi = DPBIAS; *depsbi = DEBIAS; *dra = DRA0; return; /*---------------------------------------------------------------------- ** ** Copyright (C) 2019 ** Standards Of Fundamental Astronomy Board ** of the International Astronomical Union. ** ** ===================== ** SOFA Software License ** ===================== ** ** NOTICE TO USER: ** ** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND ** CONDITIONS WHICH APPLY TO ITS USE. ** ** 1. The Software is owned by the IAU SOFA Board ("SOFA"). ** ** 2. Permission is granted to anyone to use the SOFA software for any ** purpose, including commercial applications, free of charge and ** without payment of royalties, subject to the conditions and ** restrictions listed below. ** ** 3. You (the user) may copy and distribute SOFA source code to others, ** and use and adapt its code and algorithms in your own software, ** on a world-wide, royalty-free basis. That portion of your ** distribution that does not consist of intact and unchanged copies ** of SOFA source code files is a "derived work" that must comply ** with the following requirements: ** ** a) Your work shall be marked or carry a statement that it ** (i) uses routines and computations derived by you from ** software provided by SOFA under license to you; and ** (ii) does not itself constitute software provided by and/or ** endorsed by SOFA. ** ** b) The source code of your derived work must contain descriptions ** of how the derived work is based upon, contains and/or differs ** from the original SOFA software. ** ** c) The names of all routines in your derived work shall not ** include the prefix "iau" or "sofa" or trivial modifications ** thereof such as changes of case. ** ** d) The origin of the SOFA components of your derived work must ** not be misrepresented; you must not claim that you wrote the ** original software, nor file a patent application for SOFA ** software or algorithms embedded in the SOFA software. ** ** e) These requirements must be reproduced intact in any source ** distribution and shall apply to anyone to whom you have ** granted a further right to modify the source code of your ** derived work. ** ** Note that, as originally distributed, the SOFA software is ** intended to be a definitive implementation of the IAU standards, ** and consequently third-party modifications are discouraged. All ** variations, no matter how minor, must be explicitly marked as ** such, as explained above. ** ** 4. You shall not cause the SOFA software to be brought into ** disrepute, either by misuse, or use for inappropriate tasks, or ** by inappropriate modification. ** ** 5. The SOFA software is provided "as is" and SOFA makes no warranty ** as to its use or performance. SOFA does not and cannot warrant ** the performance or results which the user may obtain by using the ** SOFA software. SOFA makes no warranties, express or implied, as ** to non-infringement of third party rights, merchantability, or ** fitness for any particular purpose. In no event will SOFA be ** liable to the user for any consequential, incidental, or special ** damages, including any lost profits or lost savings, even if a ** SOFA representative has been advised of such damages, or for any ** claim by any third party. ** ** 6. The provision of any version of the SOFA software under the terms ** and conditions specified herein does not imply that future ** versions will also be made available under the same terms and ** conditions. * ** In any published work or commercial product which uses the SOFA ** software directly, acknowledgement (see www.iausofa.org) is ** appreciated. ** ** Correspondence concerning SOFA software should be addressed as ** follows: ** ** By email: sofa@ukho.gov.uk ** By post: IAU SOFA Center ** HM Nautical Almanac Office ** UK Hydrographic Office ** Admiralty Way, Taunton ** Somerset, TA1 2DN ** United Kingdom ** **--------------------------------------------------------------------*/ }