SUBROUTINE iau_BI00 ( DPSIBI, DEPSBI, DRA ) *+ * - - - - - - - - - * i a u _ B I 0 0 * - - - - - - - - - * * Frame bias components of IAU 2000 precession-nutation models (part of * MHB2000 with additions). * * This routine is part of the International Astronomical Union's * SOFA (Standards of Fundamental Astronomy) software collection. * * Status: canonical model. * * Returned: * DPSIBI,DEPSBI d longitude and obliquity corrections * DRA d the ICRS RA of the J2000 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 pole. They define, with respect to the * GCRS frame, a J2000 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: 2008 May 12 * * Copyright (C) 2008 IAU SOFA Review Board. See notes at end. * *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION DPSIBI, DEPSBI, DRA * Arcseconds to radians DOUBLE PRECISION DAS2R PARAMETER ( DAS2R = 4.848136811095359935899141D-6 ) * The frame bias corrections in longitude and obliquity DOUBLE PRECISION DPBIAS, DEBIAS PARAMETER ( DPBIAS = -0.041775D0 * DAS2R, : DEBIAS = -0.0068192D0 * DAS2R ) * The ICRS RA of the J2000 equinox (Chapront et al., 2002) DOUBLE PRECISION DRA0 PARAMETER ( DRA0 = -0.0146D0 * DAS2R ) * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * Return the results (which are fixed). DPSIBI = DPBIAS DEPSBI = DEBIAS DRA = DRA0 * Finished. *+----------------------------------------------------------------------- * * Copyright (C) 2008 * Standards Of Fundamental Astronomy Review Board * of the International Astronomical Union. * * ===================== * SOFA Software License * ===================== * * NOTICE TO USER: * * BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING TERMS AND CONDITIONS * WHICH APPLY TO ITS USE. * * 1. The Software is owned by the IAU SOFA Review Board ("the Board"). * * 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 adapt the SOFA software and its * algorithms for your own purposes and you may copy and distribute * a resulting "derived work" to others on a world-wide, royalty-free * basis, provided that the derived work complies 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 contain * software provided by SOFA or software that has been distributed * by or endorsed by SOFA. * * b) The source code of your derived work must contain descriptions * of how the derived work is based upon and/or differs from the * original SOFA software. * * c) The name(s) of all routine(s) that you distribute shall differ * from the SOFA names, even when the SOFA content has not been * otherwise changed. * * d) The routine-naming prefix "iau" shall not be used. * * e) 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. * * f) 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. * * 4. In any published work or commercial products which includes * results achieved by using the SOFA software, you shall acknowledge * that the SOFA software was used in obtaining those results. * * 5. You shall not cause the SOFA software to be brought into * disrepute, either by misuse, or use for inappropriate tasks, or by * inappropriate modification. * * 6. The SOFA software is provided "as is" and the Board makes no * warranty as to its use or performance. The Board does not and * cannot warrant the performance or results which the user may obtain * by using the SOFA software. The Board 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 the Board be liable to the user for any consequential, * incidental, or special damages, including any lost profits or lost * savings, even if a Board representative has been advised of such * damages, or for any claim by any third party. * * 7. 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. * * Correspondence concerning SOFA software should be addressed as * follows: * * Internet email: sofa@rl.ac.uk * Postal address: IAU SOFA Center * Rutherford Appleton Laboratory * Chilton, Didcot, Oxon OX11 0QX * United Kingdom * *----------------------------------------------------------------------- END