#include "erfa.h" void eraPn00a(double date1, double date2, double *dpsi, double *deps, double *epsa, double rb[3][3], double rp[3][3], double rbp[3][3], double rn[3][3], double rbpn[3][3]) /* ** - - - - - - - - - ** e r a P n 0 0 a ** - - - - - - - - - ** ** Precession-nutation, IAU 2000A model: a multi-purpose function, ** supporting classical (equinox-based) use directly and CIO-based ** use indirectly. ** ** Given: ** date1,date2 double TT as a 2-part Julian Date (Note 1) ** ** Returned: ** dpsi,deps double nutation (Note 2) ** epsa double mean obliquity (Note 3) ** rb double[3][3] frame bias matrix (Note 4) ** rp double[3][3] precession matrix (Note 5) ** rbp double[3][3] bias-precession matrix (Note 6) ** rn double[3][3] nutation matrix (Note 7) ** rbpn double[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 ** ** 2450123.7 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. ** ** 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 eraPn00 function, where the ** nutation components are caller-specified. For faster but ** slightly less accurate results, use the eraPn00b function. ** ** 3) The mean obliquity is consistent with the IAU 2000 precession. ** ** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean ** equator and equinox by applying frame bias. ** ** 5) The matrix rp transforms vectors from J2000.0 mean equator and ** equinox to mean equator and equinox of date by applying ** precession. ** ** 6) The matrix rbp transforms vectors from GCRS to mean equator and ** equinox of date by applying frame bias then precession. It is ** the product rp x rb. ** ** 7) The matrix rn transforms vectors from mean equator and equinox ** of date to true equator and equinox of date by applying the ** nutation (luni-solar + planetary). ** ** 8) The matrix rbpn transforms vectors from GCRS to true equator and ** equinox of date. 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 GCRS-to-true matrix, ** i.e. rbpn[2][0-2]. ** ** 10) It is permissible to re-use the same array in the returned ** arguments. The arrays are filled in the order given. ** ** Called: ** eraNut00a nutation, IAU 2000A ** eraPn00 bias/precession/nutation results, IAU 2000 ** ** 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", Astron.Astrophys. 400, 1145-1154 (2003) ** ** n.b. The celestial ephemeris origin (CEO) was renamed "celestial ** intermediate origin" (CIO) by IAU 2006 Resolution 2. ** ** Copyright (C) 2013-2017, NumFOCUS Foundation. ** Derived, with permission, from the SOFA library. See notes at end of file. */ { /* Nutation. */ eraNut00a(date1, date2, dpsi, deps); /* Remaining results. */ eraPn00(date1, date2, *dpsi, *deps, epsa, rb, rp, rbp, rn, rbpn); return; } /*---------------------------------------------------------------------- ** ** ** Copyright (C) 2013-2017, NumFOCUS Foundation. ** All rights reserved. ** ** This library is derived, with permission, from the International ** Astronomical Union's "Standards of Fundamental Astronomy" library, ** available from http://www.iausofa.org. ** ** The ERFA version is intended to retain identical functionality to ** the SOFA library, but made distinct through different function and ** file names, as set out in the SOFA license conditions. The SOFA ** original has a role as a reference standard for the IAU and IERS, ** and consequently redistribution is permitted only in its unaltered ** state. The ERFA version is not subject to this restriction and ** therefore can be included in distributions which do not support the ** concept of "read only" software. ** ** Although the intent is to replicate the SOFA API (other than ** replacement of prefix names) and results (with the exception of ** bugs; any that are discovered will be fixed), SOFA is not ** responsible for any errors found in this version of the library. ** ** If you wish to acknowledge the SOFA heritage, please acknowledge ** that you are using a library derived from SOFA, rather than SOFA ** itself. ** ** ** TERMS AND CONDITIONS ** ** Redistribution and use in source and binary forms, with or without ** modification, are permitted provided that the following conditions ** are met: ** ** 1 Redistributions of source code must retain the above copyright ** notice, this list of conditions and the following disclaimer. ** ** 2 Redistributions in binary form must reproduce the above copyright ** notice, this list of conditions and the following disclaimer in ** the documentation and/or other materials provided with the ** distribution. ** ** 3 Neither the name of the Standards Of Fundamental Astronomy Board, ** the International Astronomical Union nor the names of its ** contributors may be used to endorse or promote products derived ** from this software without specific prior written permission. ** ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 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