SUBROUTINE iau_ATICQN ( RI, DI, ASTROM, N, B, RC, DC ) *+ * - - - - - - - - - - - * i a u _ A T I C Q N * - - - - - - - - - - - * * Quick CIRS to ICRS astrometric place transformation, given the * star-independent astrometry parameters plus a list of light- * deflecting bodies. * * Use of this routine is appropriate when efficiency is important and * where many star positions are all to be transformed for one date. * The star-independent astrometry parameters can be obtained by * calling one of the routines iau_APCI[13], iau_APCG[13], iau_APCO[13] * or iau_APCS[13]. * * If the only light-deflecting body to be taken into account is the * Sun, the iau_ATICQ routine can be used instead. * * This routine is part of the International Astronomical Union's * SOFA (Standards of Fundamental Astronomy) software collection. * * Status: support routine. * * Given: * RI,DI d CIRS RA,Dec (radians) * ASTROM d(30) star-independent astrometry parameters: * (1) PM time interval (SSB, Julian years) * (2-4) SSB to observer (vector, au) * (5-7) Sun to observer (unit vector) * (8) distance from Sun to observer (au) * (9-11) v: barycentric observer velocity (vector, c) * (12) sqrt(1-|v|^2): reciprocal of Lorenz factor * (13-21) bias-precession-nutation matrix * (22) longitude + s' (radians) * (23) polar motion xp wrt local meridian (radians) * (24) polar motion yp wrt local meridian (radians) * (25) sine of geodetic latitude * (26) cosine of geodetic latitude * (27) magnitude of diurnal aberration vector * (28) "local" Earth rotation angle (radians) * (29) refraction constant A (radians) * (30) refraction constant B (radians) * N i number of bodies (Note 3) * B d(8,N) data for each of the NB bodies (Notes 3,4): * (1,I) mass of the body (solar masses, Note 5) * (2,I) deflection limiter (Note 6) * (3-5,I) barycentric position of the body (au) * (6-8,I) barycentric velocity of the body (au/day) * * Returned: * RC,DC d ICRS astrometric RA,Dec (radians) * * Notes: * * 1) Iterative techniques are used for the aberration and light * deflection corrections so that the routines iau_ATICQN and * iau_ATCIQN are accurate inverses; even at the edge of the Sun's * disk the discrepancy is only about 1 nanoarcsecond. * * 2) If the only light-deflecting body to be taken into account is the * Sun, the iau_ATICQ routine can be used instead. * * 3) The array B contains N entries, one for each body to be * considered. If N = 0, no gravitational light deflection will be * applied, not even for the Sun. * * 4) The array B should include an entry for the Sun as well as for any * planet or other body to be taken into account. The entries should * be in the order in which the light passes the body. * * 5) In the entry in the B array for body I, the mass parameter B(1,I) * can, as required, be adjusted in order to allow for such effects * as quadrupole field. * * 6) The deflection limiter parameter B(2,I) is phi^2/2, where phi is * the angular separation (in radians) between star and body at which * limiting is applied. As phi shrinks below the chosen threshold, * the deflection is artificially reduced, reaching zero for phi = 0. * Example values suitable for a terrestrial observer, together with * masses, are as follows: * * body I B(1,I) B(2,I) * * Sun 1D0 6D-6 * Jupiter 0.00095435D0 3D-9 * Saturn 0.00028574D0 3D-10 * * 7) For efficiency, validation of the contents of the B array is * omitted. The supplied masses must be greater than zero, the * position and velocity vectors must be right, and the deflection * limiter greater than zero. * * Called: * iau_S2C spherical coordinates to unit vector * iau_TRXP product of transpose of r-matrix and p-vector * iau_ZP zero p-vector * iau_AB stellar aberration * iau_LDN light deflection by n bodies * iau_C2S p-vector to spherical * iau_ANP normalize angle into range +/- pi * * This revision: 2013 September 30 * * SOFA release 2020-07-21 * * Copyright (C) 2020 IAU SOFA Board. See notes at end. * *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION RI, DI, ASTROM(30) INTEGER N DOUBLE PRECISION B(8,N), RC, DC INTEGER J, I DOUBLE PRECISION PI(3), PPR(3), PNAT(3), PCO(3), W, D(3), : BEFORE(3), R2, R, AFTER(3) DOUBLE PRECISION iau_ANP * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * CIRS RA,Dec to Cartesian. CALL iau_S2C ( RI, DI, PI ) * Bias-precession-nutation, giving GCRS proper direction. CALL iau_TRXP ( ASTROM(13), PI, PPR ) * Aberration, giving GCRS natural direction. CALL iau_ZP ( D ) DO 50 J=1,2 R2 = 0D0 DO 10 I=1,3 W = PPR(I) - D(I) BEFORE(I) = W R2 = R2 + W*W 10 CONTINUE R = SQRT ( R2 ) DO 20 I=1,3 BEFORE(I) = BEFORE(I) / R 20 CONTINUE CALL iau_AB ( BEFORE, ASTROM(9), ASTROM(8), ASTROM(12), AFTER ) R2 = 0D0 DO 30 I=1,3 D(I) = AFTER(I) - BEFORE(I) W = PPR(I) - D(I) PNAT(I) = W R2 = R2 + W*W 30 CONTINUE R = SQRT ( R2 ) DO 40 I=1,3 PNAT(I) = PNAT(I) / R 40 CONTINUE 50 CONTINUE * Light deflection, giving BCRS coordinate direction. CALL iau_ZP ( D ) DO 100 J=1,5 R2 = 0D0 DO 60 I=1,3 W = PNAT(I) - D(I) BEFORE(I) = W R2 = R2 + W*W 60 CONTINUE R = SQRT ( R2 ) DO 70 I=1,3 BEFORE(I) = BEFORE(I) / R 70 CONTINUE CALL iau_LDN ( N, B, ASTROM(2), BEFORE, AFTER ) R2 = 0D0 DO 80 I=1,3 D(I) = AFTER(I) - BEFORE(I) W = PNAT(I) - D(I) PCO(I) = W R2 = R2 + W*W 80 CONTINUE R = SQRT ( R2 ) DO 90 I=1,3 PCO(I) = PCO(I) / R 90 CONTINUE 100 CONTINUE * ICRS astrometric RA,Dec. CALL iau_C2S ( PCO, W, DC ) RC = iau_ANP ( W ) * Finished. *+---------------------------------------------------------------------- * * Copyright (C) 2020 * 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. 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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 * *----------------------------------------------------------------------- END