1 /*
2 * - - - - - - - - - -
3 * g a l _ p n 0 6 a
4 * - - - - - - - - - -
5 *
6 * This routine is part of the General Astrodynamics Library
7 *
8 * Description:
9 *
10 * Precession-nutation, IAU 2006/2000A models: a multi-purpose routine,
11 * supporting classical (equinox-based) use directly and CIO-based use
12 * indirectly.
13 *
14 * This routine is an independent translation of a FORTRAN routine
15 * that is part of IAU's SOFA software collection.
16 *
17 * Status:
18 *
19 * support routine.
20 *
21 * Given:
22 *
23 * date1,date2 d TT as a 2-part Julian Date (Note 1)
24 *
25 * Returned:
26 *
27 * *dpsi,*deps d nutation (Note 2)
28 * *epsa d mean obliquity (Note 3)
29 * rb d[3][3] frame bias matrix (Note 4)
30 * rp d[3][3] precession matrix (Note 5)
31 * rbp d[3][3] bias-precession matrix (Note 6)
32 * rn d[3][3] nutation matrix (Note 7)
33 * rbpn d[3][3] GCRS-to-true matrix (Notes 8,9)
34 *
35 * Notes:
36 *
37 * 1) The TT date date1+date2 is a Julian Date, apportioned in any
38 * convenient way between the two arguments. For example,
39 * JD(TT)=2450123.7 could be expressed in any of these ways,
40 * among others:
41 *
42 * date1 date2
43 *
44 * 2450123.7 0.0 (JD method)
45 * 2451545.0 -1421.3 (J2000 method)
46 * 2400000.5 50123.2 (MJD method)
47 * 2450123.5 0.2 (date & time method)
48 *
49 * The JD method is the most natural and convenient to use in
50 * cases where the loss of several decimal digits of resolution
51 * is acceptable. The J2000 method is best matched to the way
52 * the argument is handled internally and will deliver the
53 * optimum resolution. The MJD method and the date & time methods
54 * are both good compromises between resolution and convenience.
55 *
56 * 2) The nutation components (luni-solar + planetary, IAU 2000A) in
57 * longitude and obliquity are in radians and with respect to the
58 * equinox and ecliptic of date. Free core nutation is omitted; for
59 * the utmost accuracy, use the gal_PN06 routine, where the nutation
60 * components are caller-specified.
61 *
62 * 3) The mean obliquity is consistent with the IAU 2006 precession.
63 *
64 * 4) The matrix rb transforms vectors from GCRS to mean J2000 by
65 * applying frame bias.
66 *
67 * 5) The matrix rp transforms vectors from mean J2000 to mean of date
68 * by applying precession.
69 *
70 * 6) The matrix rbp transforms vectors from GCRS to mean of date by
71 * applying frame bias then precession. It is the product RP x RB.
72 *
73 * 7) The matrix rn transforms vectors from mean of date to true of date
74 * by applying the nutation (luni-solar + planetary).
75 *
76 * 8) The matrix rbpn transforms vectors from GCRS to true of date
77 * (CIP/equinox). It is the product rn x rbp, applying frame bias,
78 * precession and nutation in that order.
79 *
80 * 9) The X,Y,Z coordinates of the IAU 2006/2000A Celestial Intermediate
81 * Pole are elements [0-2][2] of the matrix rbpn.
82 *
83 * Called:
84 *
85 * gal_nut06a nutation, IAU 2006/2000A
86 * gal_pn06 bias/precession/nutation results, IAU 2006
87 *
88 * References:
89 *
90 * Capitaine, N. & Wallace, P.T., 2006, Astron.Astrophys. 450, 855
91 *
92 * This revision:
93 *
94 * 2007 May 11 ( c version 2008 February 4 )
95 *
96 *
97 * Copyright (C) 2008 Paul C. L. Willmott. See notes at end.
98 *
99 *-----------------------------------------------------------------------
100 */
101
102 #include "gal_pn06a.h"
103 #include "gal_nut06a.h"
104 #include "gal_pn06.h"
105
106 void
gal_pn06a(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])107 gal_pn06a
108 (
109 double date1,
110 double date2,
111 double *dpsi,
112 double *deps,
113 double *epsa,
114 double rb[3][3],
115 double rp[3][3],
116 double rbp[3][3],
117 double rn[3][3],
118 double rbpn[3][3]
119 )
120 {
121
122 /*
123 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
124 */
125
126 /*
127 * Nutation.
128 */
129
130 gal_nut06a ( date1, date2, dpsi, deps ) ;
131
132 /*
133 * Remaining results.
134 */
135
136 gal_pn06 ( date1, date2, *dpsi, *deps, epsa, rb, rp, rbp, rn, rbpn ) ;
137
138 /*
139 * Finished.
140 */
141
142 }
143
144 /*
145 * gal - General Astrodynamics Library
146 * Copyright (C) 2008 Paul C. L. Willmott
147 *
148 * This program is free software; you can redistribute it and/or modify
149 * it under the terms of the GNU General Public License as published by
150 * the Free Software Foundation; either version 2 of the License, or
151 * (at your option) any later version.
152 *
153 * This program is distributed in the hope that it will be useful,
154 * but WITHOUT ANY WARRANTY; without even the implied warranty of
155 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
156 * GNU General Public License for more details.
157 *
158 * You should have received a copy of the GNU General Public License along
159 * with this program; if not, write to the Free Software Foundation, Inc.,
160 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
161 *
162 * Contact:
163 *
164 * Paul Willmott
165 * vp9mu@amsat.org
166 */
167