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palPrebn.c
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palPrebn.c
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/*
*+
* Name:
* palPrebn
* Purpose:
* Generate the matrix of precession between two objects (old)
* Language:
* Starlink ANSI C
* Type of Module:
* Library routine
* Invocation:
* void palPrebn ( double bep0, double bep1, double rmatp[3][3] );
* Arguments:
* bep0 = double (Given)
* Beginning Besselian epoch.
* bep1 = double (Given)
* Ending Besselian epoch
* rmatp = double[3][3] (Returned)
* precession matrix in the sense V(BEP1) = RMATP * V(BEP0)
* Description:
* Generate the matrix of precession between two epochs,
* using the old, pre-IAU1976, Bessel-Newcomb model, using
* Kinoshita's formulation
* Authors:
* PTW: Pat Wallace (STFC)
* TIMJ: Tim Jenness (JAC, Hawaii)
* {enter_new_authors_here}
* See Also:
* Kinoshita, H. (1975) 'Formulas for precession', SAO Special
* Report No. 364, Smithsonian Institution Astrophysical
* Observatory, Cambridge, Massachusetts.
* History:
* 2012-02-12(TIMJ):
* Initial version with documentation taken from Fortran SLA
* Adapted with permission from the Fortran SLALIB library.
* {enter_further_changes_here}
* Copyright:
* Copyright (C) 1996 Rutherford Appleton Laboratory
* Copyright (C) 2012 Science and Technology Facilities Council.
* All Rights Reserved.
* Licence:
* This program is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either
* version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* License along with this program. If not, see
* <http://www.gnu.org/licenses/>.
* Bugs:
* {note_any_bugs_here}
*-
*/
#include "pal.h"
#include "palmac.h"
void palPrebn ( double bep0, double bep1, double rmatp[3][3] ) {
double t,bigt, zeta, theta, z, tas2r, w;
/* Interval between basic epoch B1850.0 and beginning epoch in TC */
bigt = (bep0-1850)/100.;
/* Interval over which precession required, in tropical centuries */
t = (bep1-bep0)/100.;
/* Euler angles */
tas2r = t * PAL__DAS2R;
w = 2303.5548 + ( 1.39720 + 0.000059 * bigt) * bigt;
zeta = ( w + ( 0.30242 - 0.000269 * bigt + 0.017996 * t ) * t ) * tas2r;
z = ( w + ( 1.09478 + 0.000387 * bigt + 0.018324 * t ) * t ) * tas2r;
theta = ( 2005.1125 + ( -0.85294 - 0.000365 * bigt ) * bigt +
(-0.42647 - 0.000365 * bigt - 0.041802 * t ) * t ) * tas2r;
/* Rotation matrix */
palDeuler("ZYZ", -zeta, theta, -z, rmatp);
}