diff options
Diffstat (limited to 'ast/erfa/ltpequ.c')
| -rw-r--r-- | ast/erfa/ltpequ.c | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/ast/erfa/ltpequ.c b/ast/erfa/ltpequ.c deleted file mode 100644 index 354ce32..0000000 --- a/ast/erfa/ltpequ.c +++ /dev/null @@ -1,177 +0,0 @@ -#include "erfa.h" - -void eraLtpequ(double epj, double veq[3]) -/* -** - - - - - - - - - - -** e r a L t p e q u -** - - - - - - - - - - -** -** Long-term precession of the equator. -** -** Given: -** epj double Julian epoch (TT) -** -** Returned: -** veq double[3] equator 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. -*/ -{ -/* Polynomial coefficients */ - enum { NPOL = 4 }; - static const double xypol[2][NPOL] = { - { 5453.282155, - 0.4252841, - -0.00037173, - -0.000000152}, - {-73750.930350, - -0.7675452, - -0.00018725, - 0.000000231} - }; - -/* Periodic coefficients */ - static const double xyper[][5] = { - { 256.75, -819.940624,75004.344875,81491.287984, 1558.515853}, - { 708.15,-8444.676815, 624.033993, 787.163481, 7774.939698}, - { 274.20, 2600.009459, 1251.136893, 1251.296102,-2219.534038}, - { 241.45, 2755.175630,-1102.212834,-1257.950837,-2523.969396}, - {2309.00, -167.659835,-2660.664980,-2966.799730, 247.850422}, - { 492.20, 871.855056, 699.291817, 639.744522, -846.485643}, - { 396.10, 44.769698, 153.167220, 131.600209,-1393.124055}, - { 288.90, -512.313065, -950.865637, -445.040117, 368.526116}, - { 231.10, -819.415595, 499.754645, 584.522874, 749.045012}, - {1610.00, -538.071099, -145.188210, -89.756563, 444.704518}, - { 620.00, -189.793622, 558.116553, 524.429630, 235.934465}, - { 157.87, -402.922932, -23.923029, -13.549067, 374.049623}, - { 220.30, 179.516345, -165.405086, -210.157124, -171.330180}, - {1200.00, -9.814756, 9.344131, -44.919798, -22.899655} - }; - static const int NPER = (int) ( sizeof xyper / 5 / sizeof (double) ); - -/* Miscellaneous */ - int i; - double t, x, y, w, a, s, c; - - -/* Centuries since J2000. */ - t = ( epj - 2000.0 ) / 100.0; - -/* Initialize X and Y accumulators. */ - x = 0.0; - y = 0.0; - -/* Periodic terms. */ - w = ERFA_D2PI * t; - for ( i = 0; i < NPER; i++ ) { - a = w / xyper[i][0]; - s = sin(a); - c = cos(a); - x += c*xyper[i][1] + s*xyper[i][3]; - y += c*xyper[i][2] + s*xyper[i][4]; - } - -/* Polynomial terms. */ - w = 1.0; - for ( i = 0; i < NPOL; i++ ) { - x += xypol[0][i]*w; - y += xypol[1][i]*w; - w *= t; - } - -/* X and Y (direction cosines). */ - x *= ERFA_DAS2R; - y *= ERFA_DAS2R; - -/* Form the equator pole vector. */ - veq[0] = x; - veq[1] = y; - w = 1.0 - x*x - y*y; - veq[2] = w < 0.0 ? 0.0 : sqrt(w); - -} -/*---------------------------------------------------------------------- -** -** -** 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. -** -*/ |