SUBROUTINE iau_PN00A ( DATE1, DATE2, : DPSI, DEPS, EPSA, RB, RP, RBP, RN, RBPN ) *+ * - - - - - - - - - - * i a u _ P N 0 0 A * - - - - - - - - - - * * Precession-nutation, IAU 2000A model; a multi-purpose routine, * supporting both classical equinox-based use (directly) and CEO-based * use (indirectly). * * This routine is part of the International Astronomical Union's * SOFA (Standards of Fundamental Astronomy) software collection. * * Status: support routine. * * Given: * DATE1,DATE2 d TT as a 2-part Julian Date (Note 1) * * Returned: * DPSI,DEPS d nutation (Note 2) * EPSA d mean obliquity (Note 3) * RB d(3,3) frame bias matrix (Note 4) * RP d(3,3) precession matrix (Note 5) * RBP d(3,3) bias-precession matrix (Note 6) * RN d(3,3) nutation matrix (Note 7) * RBPN d(3,3) GCRS-to-true matrix (Notes 8,9) * * Notes: * * 1) The TT date DATE1+DATE2 is a Julian Date, apportioned in any * convenient way between the two arguments. For example, * JD(TT)=2450123.7 could be expressed in any of these ways, * among others: * * DATE1 DATE2 * * 2450123.7D0 0D0 (JD method) * 2451545D0 -1421.3D0 (J2000 method) * 2400000.5D0 50123.2D0 (MJD method) * 2450123.5D0 0.2D0 (date & time method) * * The JD method is the most natural and convenient to use in * cases where the loss of several decimal digits of resolution * is acceptable. The J2000 method is best matched to the way * the argument is handled internally and will deliver the * optimum resolution. The MJD method and the date & time methods * are both good compromises between resolution and convenience. * * 2) The nutation components (luni-solar + planetary, IAU 2000A) in * longitude and obliquity are in radians and with respect to the * equinox and ecliptic of date. Free core nutation is omitted; for * the utmost accuracy, use the iau_PN00 routine, where the nutation * components are caller-specified. For faster but slightly less * accurate results, use the iau_PN00B routine. * * 3) The mean obliquity is consistent with the IAU 2000 precession- * nutation models. * * 4) The matrix RB transforms vectors from GCRS to mean J2000 by * applying frame bias. * * 5) The matrix RP transforms vectors from mean J2000 to mean of date * by applying precession. * * 6) The matrix RBP transforms vectors from GCRS to mean of date by * applying frame bias then precession. It is the product RP x RB. * * 7) The matrix RN transforms vectors from mean of date to true of date * by applying the nutation (luni-solar + planetary). * * 8) The matrix RBPN transforms vectors from GCRS to true of date * (CIP/equinox). It is the product RN x RBP, applying frame bias, * precession and nutation in that order. * * 9) The X,Y,Z coordinates of the IAU 2000A Celestial Intermediate Pole * are elements (3,1-3) of the matrix RBPN. * * Called: * iau_NUT00A nutation, IAU 2000A * iau_PN00 bias/precession/nutation results * * Reference: * * Capitaine, N., Chapront, J., Lambert, S. and Wallace, P., * "Expressions for the Celestial Intermediate Pole and Celestial * Ephemeris Origin consistent with the IAU 2000A precession-nutation * model", submitted to A&A (2002) * * This revision: 2002 December 25 * * Copyright (C) 2003 IAU SOFA Review Board. See notes at end. * *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION DATE1, DATE2, DPSI, DEPS, EPSA, : RB(3,3), RP(3,3), RBP(3,3), RN(3,3), RBPN(3,3) * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * Nutation. CALL iau_NUT00A ( DATE1, DATE2, DPSI, DEPS ) * Remaining results. CALL iau_PN00 ( DATE1, DATE2, DPSI, DEPS, : EPSA, RB, RP, RBP, RN, RBPN ) * Finished. *+---------------------------------------------------------------------- * * Copyright (C) 2003 * 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. The Software is made available free of charge for use by: * * a) private individuals for non-profit research; and * * b) non-profit educational, academic and research institutions. * * 3. Commercial use of the Software is specifically excluded from the * terms and conditions of this license. Commercial use of the * Software is subject to the prior written agreement of the Board on * terms to be agreed. * * 4. The provision of any version of the 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. * * 5. The user may modify the Software for his/her own purposes. The * user may distribute the modified software provided that the Board * is informed and that a copy of the modified software is made * available to the Board on request. All modifications made by the * user shall be clearly identified to show how the modified software * differs from the original Software, and the name(s) of the * affected routine(s) shall be changed. The original SOFA Software * License text must be present. * * 6. In any published work produced by the user and which includes * results achieved by using the Software, the user shall acknowledge * that the Software was used in producing the information contained * in such publication. * * 7. The user may incorporate or embed the Software into other software * products which he/she may then give away free of charge but not * sell provided the user makes due acknowledgement of the use which * he/she has made of the Software in creating such software * products. Any redistribution of the Software in this way shall be * made under the same terms and conditions under which the user * received it from the SOFA Center. * * 8. The user shall not cause the Software to be brought into * disrepute, either by misuse, or use for inappropriate tasks, or by * inappropriate modification. * * 9. The Software is provided to the user "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 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. * * 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