SUBROUTINE iau_ATCI13 ( RC, DC, PR, PD, PX, RV, DATE1, DATE2, : RI, DI, EO ) *+ * - - - - - - - - - - - * i a u _ A T C I 1 3 * - - - - - - - - - - - * * Transform ICRS star data, epoch J2000.0, to CIRS. * * This routine is part of the International Astronomical Union's * SOFA (Standards of Fundamental Astronomy) software collection. * * Status: support routine. * * Given: * RC d ICRS right ascension at J2000.0 (radians, Note 1) * DC d ICRS declination at J2000.0 (radians, Note 1) * PR d RA proper motion (radians/year; Note 2) * PD d Dec proper motion (radians/year) * PX d parallax (arcsec) * RV d radial velocity (km/s, +ve if receding) * DATE1 d TDB as a 2-part... * DATE2 d ...Julian Date (Note 3) * * Returned: * RI,DI d CIRS geocentric RA,Dec (radians) * EO d equation of the origins (ERA-GST, Note 5) * * Notes: * * 1) Star data for an epoch other than J2000.0 (for example from the * Hipparcos catalog, which has an epoch of J1991.25) will require a * preliminary call to iau_PMSAFE before use. * * 2) The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt. * * 3) The TDB date DATE1+DATE2 is a Julian Date, apportioned in any * convenient way between the two arguments. For example, * JD(TDB)=2450123.8g could be expressed in any of these ways, among * others: * * DATE1 DATE2 * * 2450123.8g 0.0 (JD method) * 2451545.0 -1421.3 (J2000 method) * 2400000.5 50123.2 (MJD method) * 2450123.5 0.2 (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. For most * applications of this routine the choice will not be at all * critical. * * TT can be used instead of TDB without any significant impact on * accuracy. * * 4) The available accuracy is better than 1 milliarcsecond, limited * mainly by the precession-nutation model that is used, namely * IAU 2000A/2006. Very close to solar system bodies, additional * errors of up to several milliarcseconds can occur because of * unmodeled light deflection; however, the Sun's contribution is * taken into account, to first order. The accuracy limitations of * the SOFA routine iau_EPV00 (used to compute Earth position and * velocity) can contribute aberration errors of up to * 5 microarcseconds. Light deflection at the Sun's limb is * uncertain at the 0.4 mas level. * * 5) Should the transformation to (equinox based) apparent place be * required rather than (CIO based) intermediate place, subtract the * equation of the origins from the returned right ascension: * RA = RI - EO. (The iau_ANP routine can then be applied, as * required, to keep the result in the conventional 0-2pi range.) * * Called: * iau_APCI13 astrometry parameters, ICRS-CIRS, 2013 * iau_ATCIQ quick ICRS to CIRS * * This revision: 2013 August 22 * * SOFA release 2013-12-02 * * Copyright (C) 2013 IAU SOFA Board. See notes at end. * *----------------------------------------------------------------------- IMPLICIT NONE DOUBLE PRECISION RC, DC, PR, PD, PX, RV, DATE1, DATE2, RI, DI, EO * Star-independent astrometry parameters DOUBLE PRECISION ASTROM(30) * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - * The transformation parameters. CALL iau_APCI13 ( DATE1, DATE2, ASTROM, EO ) * ICRS (epoch J2000.0) to CIRS. CALL iau_ATCIQ ( RC, DC, PR, PD, PX, RV, ASTROM, RI, DI ) * Finished. *+---------------------------------------------------------------------- * * Copyright (C) 2013 * 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 * *----------------------------------------------------------------------- END