| 1 | /*
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| 2 | *+
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| 3 | * Name:
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| 4 | * palPrebn
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| 5 |
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| 6 | * Purpose:
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| 7 | * Generate the matrix of precession between two objects (old)
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| 8 |
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| 9 | * Language:
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| 10 | * Starlink ANSI C
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| 11 |
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| 12 | * Type of Module:
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| 13 | * Library routine
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| 14 |
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| 15 | * Invocation:
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| 16 | * void palPrebn ( double bep0, double bep1, double rmatp[3][3] );
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| 17 |
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| 18 | * Arguments:
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| 19 | * bep0 = double (Given)
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| 20 | * Beginning Besselian epoch.
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| 21 | * bep1 = double (Given)
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| 22 | * Ending Besselian epoch
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| 23 | * rmatp = double[3][3] (Returned)
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| 24 | * precession matrix in the sense V(BEP1) = RMATP * V(BEP0)
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| 25 |
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| 26 | * Description:
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| 27 | * Generate the matrix of precession between two epochs,
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| 28 | * using the old, pre-IAU1976, Bessel-Newcomb model, using
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| 29 | * Kinoshita's formulation
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| 30 |
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| 31 | * Authors:
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| 32 | * PTW: Pat Wallace (STFC)
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| 33 | * TIMJ: Tim Jenness (JAC, Hawaii)
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| 34 | * {enter_new_authors_here}
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| 35 |
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| 36 | * See Also:
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| 37 | * Kinoshita, H. (1975) 'Formulas for precession', SAO Special
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| 38 | * Report No. 364, Smithsonian Institution Astrophysical
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| 39 | * Observatory, Cambridge, Massachusetts.
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| 40 |
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| 41 | * History:
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| 42 | * 2012-02-12(TIMJ):
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| 43 | * Initial version with documentation taken from Fortran SLA
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| 44 | * Adapted with permission from the Fortran SLALIB library.
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| 45 | * {enter_further_changes_here}
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| 46 |
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| 47 | * Copyright:
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| 48 | * Copyright (C) 1996 Rutherford Appleton Laboratory
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| 49 | * Copyright (C) 2012 Science and Technology Facilities Council.
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| 50 | * All Rights Reserved.
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| 51 |
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| 52 | * Licence:
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| 53 | * This program is free software: you can redistribute it and/or
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| 54 | * modify it under the terms of the GNU Lesser General Public
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| 55 | * License as published by the Free Software Foundation, either
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| 56 | * version 3 of the License, or (at your option) any later
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| 57 | * version.
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| 58 | *
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| 59 | * This program is distributed in the hope that it will be useful,
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| 60 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 61 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 62 | * GNU Lesser General Public License for more details.
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| 63 | *
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| 64 | * You should have received a copy of the GNU Lesser General
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| 65 | * License along with this program. If not, see
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| 66 | * <http://www.gnu.org/licenses/>.
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| 67 |
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| 68 | * Bugs:
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| 69 | * {note_any_bugs_here}
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| 70 | *-
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| 71 | */
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| 72 |
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| 73 | #include "pal.h"
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| 74 | #include "palmac.h"
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| 75 |
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| 76 | void palPrebn ( double bep0, double bep1, double rmatp[3][3] ) {
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| 77 |
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| 78 | double t,bigt, zeta, theta, z, tas2r, w;
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| 79 |
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| 80 | /* Interval between basic epoch B1850.0 and beginning epoch in TC */
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| 81 | bigt = (bep0-1850)/100.;
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| 82 |
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| 83 | /* Interval over which precession required, in tropical centuries */
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| 84 | t = (bep1-bep0)/100.;
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| 85 |
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| 86 | /* Euler angles */
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| 87 | tas2r = t * PAL__DAS2R;
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| 88 | w = 2303.5548 + ( 1.39720 + 0.000059 * bigt) * bigt;
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| 89 |
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| 90 | zeta = ( w + ( 0.30242 - 0.000269 * bigt + 0.017996 * t ) * t ) * tas2r;
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| 91 | z = ( w + ( 1.09478 + 0.000387 * bigt + 0.018324 * t ) * t ) * tas2r;
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| 92 | theta = ( 2005.1125 + ( -0.85294 - 0.000365 * bigt ) * bigt +
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| 93 | (-0.42647 - 0.000365 * bigt - 0.041802 * t ) * t ) * tas2r;
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| 94 |
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| 95 | /* Rotation matrix */
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| 96 | palDeuler("ZYZ", -zeta, theta, -z, rmatp);
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| 97 |
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| 98 | }
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