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Diffstat (limited to 'ast/erfa/ltpecl.c')
| -rw-r--r-- | ast/erfa/ltpecl.c | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/ast/erfa/ltpecl.c b/ast/erfa/ltpecl.c deleted file mode 100644 index feb3d55..0000000 --- a/ast/erfa/ltpecl.c +++ /dev/null @@ -1,177 +0,0 @@ -#include "erfa.h" - -void eraLtpecl(double epj, double vec[3]) -/* -** - - - - - - - - - - -** e r a L t p e c l -** - - - - - - - - - - -** -** Long-term precession of the ecliptic. -** -** Given: -** epj double Julian epoch (TT) -** -** Returned: -** vec double[3] ecliptic pole unit vector -** -** Notes: -** -** 1) The returned vector is with respect to the J2000.0 mean equator -** and equinox. -** -** 2) The Vondrak et al. (2011, 2012) 400 millennia precession model -** agrees with the IAU 2006 precession at J2000.0 and stays within -** 100 microarcseconds during the 20th and 21st centuries. It is -** accurate to a few arcseconds throughout the historical period, -** worsening to a few tenths of a degree at the end of the -** +/- 200,000 year time span. -** -** References: -** -** Vondrak, J., Capitaine, N. and Wallace, P., 2011, New precession -** expressions, valid for long time intervals, Astron.Astrophys. 534, -** A22 -** -** Vondrak, J., Capitaine, N. and Wallace, P., 2012, New precession -** expressions, valid for long time intervals (Corrigendum), -** Astron.Astrophys. 541, C1 -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** Derived, with permission, from the SOFA library. See notes at end of file. -*/ -{ -/* Obliquity at J2000.0 (radians). */ - static const double eps0 = 84381.406 * ERFA_DAS2R; - -/* Polynomial coefficients */ - enum { NPOL = 4 }; - static const double pqpol[2][NPOL] = { - { 5851.607687, - -0.1189000, - -0.00028913, - 0.000000101}, - {-1600.886300, - 1.1689818, - -0.00000020, - -0.000000437} - }; - -/* Periodic coefficients */ - static const double pqper[][5] = { - { 708.15,-5486.751211,-684.661560, 667.666730,-5523.863691}, - {2309.00, -17.127623,2446.283880,-2354.886252, -549.747450}, - {1620.00, -617.517403, 399.671049, -428.152441, -310.998056}, - { 492.20, 413.442940,-356.652376, 376.202861, 421.535876}, - {1183.00, 78.614193,-186.387003, 184.778874, -36.776172}, - { 622.00, -180.732815,-316.800070, 335.321713, -145.278396}, - { 882.00, -87.676083, 198.296701, -185.138669, -34.744450}, - { 547.00, 46.140315, 101.135679, -120.972830, 22.885731} - }; - static const int NPER = (int) ( sizeof pqper / 5 / sizeof (double) ); - -/* Miscellaneous */ - int i; - double t, p, q, w, a, s, c; - - -/* Centuries since J2000. */ - t = ( epj - 2000.0 ) / 100.0; - -/* Initialize P_A and Q_A accumulators. */ - p = 0.0; - q = 0.0; - -/* Periodic terms. */ - w = ERFA_D2PI*t; - for ( i = 0; i < NPER; i++ ) { - a = w/pqper[i][0]; - s = sin(a); - c = cos(a); - p += c*pqper[i][1] + s*pqper[i][3]; - q += c*pqper[i][2] + s*pqper[i][4]; - } - -/* Polynomial terms. */ - w = 1.0; - for ( i = 0; i < NPOL; i++ ) { - p += pqpol[0][i]*w; - q += pqpol[1][i]*w; - w *= t; - } - -/* P_A and Q_A (radians). */ - p *= ERFA_DAS2R; - q *= ERFA_DAS2R; - -/* Form the ecliptic pole vector. */ - w = 1.0 - p*p - q*q; - w = w < 0.0 ? 0.0 : sqrt(w); - s = sin(eps0); - c = cos(eps0); - vec[0] = p; - vec[1] = - q*c - w*s; - vec[2] = - q*s + w*c; - -} -/*---------------------------------------------------------------------- -** -** -** Copyright (C) 2013-2016, 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. IN NO EVENT SHALL THE -** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -** POSSIBILITY OF SUCH DAMAGE. -** -*/ |