1 #include "erfa.h"
2
eraPn00(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])3 void eraPn00(double date1, double date2, double dpsi, double deps,
4 double *epsa,
5 double rb[3][3], double rp[3][3], double rbp[3][3],
6 double rn[3][3], double rbpn[3][3])
7 /*
8 ** - - - - - - - -
9 ** e r a P n 0 0
10 ** - - - - - - - -
11 **
12 ** Precession-nutation, IAU 2000 model: a multi-purpose function,
13 ** supporting classical (equinox-based) use directly and CIO-based
14 ** use indirectly.
15 **
16 ** Given:
17 ** date1,date2 double TT as a 2-part Julian Date (Note 1)
18 ** dpsi,deps double nutation (Note 2)
19 **
20 ** Returned:
21 ** epsa double mean obliquity (Note 3)
22 ** rb double[3][3] frame bias matrix (Note 4)
23 ** rp double[3][3] precession matrix (Note 5)
24 ** rbp double[3][3] bias-precession matrix (Note 6)
25 ** rn double[3][3] nutation matrix (Note 7)
26 ** rbpn double[3][3] GCRS-to-true matrix (Note 8)
27 **
28 ** Notes:
29 **
30 ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
31 ** convenient way between the two arguments. For example,
32 ** JD(TT)=2450123.7 could be expressed in any of these ways,
33 ** among others:
34 **
35 ** date1 date2
36 **
37 ** 2450123.7 0.0 (JD method)
38 ** 2451545.0 -1421.3 (J2000 method)
39 ** 2400000.5 50123.2 (MJD method)
40 ** 2450123.5 0.2 (date & time method)
41 **
42 ** The JD method is the most natural and convenient to use in
43 ** cases where the loss of several decimal digits of resolution
44 ** is acceptable. The J2000 method is best matched to the way
45 ** the argument is handled internally and will deliver the
46 ** optimum resolution. The MJD method and the date & time methods
47 ** are both good compromises between resolution and convenience.
48 **
49 ** 2) The caller is responsible for providing the nutation components;
50 ** they are in longitude and obliquity, in radians and are with
51 ** respect to the equinox and ecliptic of date. For high-accuracy
52 ** applications, free core nutation should be included as well as
53 ** any other relevant corrections to the position of the CIP.
54 **
55 ** 3) The returned mean obliquity is consistent with the IAU 2000
56 ** precession-nutation models.
57 **
58 ** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
59 ** equator and equinox by applying frame bias.
60 **
61 ** 5) The matrix rp transforms vectors from J2000.0 mean equator and
62 ** equinox to mean equator and equinox of date by applying
63 ** precession.
64 **
65 ** 6) The matrix rbp transforms vectors from GCRS to mean equator and
66 ** equinox of date by applying frame bias then precession. It is
67 ** the product rp x rb.
68 **
69 ** 7) The matrix rn transforms vectors from mean equator and equinox of
70 ** date to true equator and equinox of date by applying the nutation
71 ** (luni-solar + planetary).
72 **
73 ** 8) The matrix rbpn transforms vectors from GCRS to true equator and
74 ** equinox of date. It is the product rn x rbp, applying frame
75 ** bias, precession and nutation in that order.
76 **
77 ** 9) It is permissible to re-use the same array in the returned
78 ** arguments. The arrays are filled in the order given.
79 **
80 ** Called:
81 ** eraPr00 IAU 2000 precession adjustments
82 ** eraObl80 mean obliquity, IAU 1980
83 ** eraBp00 frame bias and precession matrices, IAU 2000
84 ** eraCr copy r-matrix
85 ** eraNumat form nutation matrix
86 ** eraRxr product of two r-matrices
87 **
88 ** Reference:
89 **
90 ** Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
91 ** "Expressions for the Celestial Intermediate Pole and Celestial
92 ** Ephemeris Origin consistent with the IAU 2000A precession-
93 ** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
94 **
95 ** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
96 ** intermediate origin" (CIO) by IAU 2006 Resolution 2.
97 **
98 ** Copyright (C) 2013-2014, NumFOCUS Foundation.
99 ** Derived, with permission, from the SOFA library. See notes at end of file.
100 */
101 {
102 double dpsipr, depspr, rbpw[3][3], rnw[3][3];
103
104
105 /* IAU 2000 precession-rate adjustments. */
106 eraPr00(date1, date2, &dpsipr, &depspr);
107
108 /* Mean obliquity, consistent with IAU 2000 precession-nutation. */
109 *epsa = eraObl80(date1, date2) + depspr;
110
111 /* Frame bias and precession matrices and their product. */
112 eraBp00(date1, date2, rb, rp, rbpw);
113 eraCr(rbpw, rbp);
114
115 /* Nutation matrix. */
116 eraNumat(*epsa, dpsi, deps, rnw);
117 eraCr(rnw, rn);
118
119 /* Bias-precession-nutation matrix (classical). */
120 eraRxr(rnw, rbpw, rbpn);
121
122 return;
123
124 }
125 /*----------------------------------------------------------------------
126 **
127 **
128 ** Copyright (C) 2013-2014, NumFOCUS Foundation.
129 ** All rights reserved.
130 **
131 ** This library is derived, with permission, from the International
132 ** Astronomical Union's "Standards of Fundamental Astronomy" library,
133 ** available from http://www.iausofa.org.
134 **
135 ** The ERFA version is intended to retain identical functionality to
136 ** the SOFA library, but made distinct through different function and
137 ** file names, as set out in the SOFA license conditions. The SOFA
138 ** original has a role as a reference standard for the IAU and IERS,
139 ** and consequently redistribution is permitted only in its unaltered
140 ** state. The ERFA version is not subject to this restriction and
141 ** therefore can be included in distributions which do not support the
142 ** concept of "read only" software.
143 **
144 ** Although the intent is to replicate the SOFA API (other than
145 ** replacement of prefix names) and results (with the exception of
146 ** bugs; any that are discovered will be fixed), SOFA is not
147 ** responsible for any errors found in this version of the library.
148 **
149 ** If you wish to acknowledge the SOFA heritage, please acknowledge
150 ** that you are using a library derived from SOFA, rather than SOFA
151 ** itself.
152 **
153 **
154 ** TERMS AND CONDITIONS
155 **
156 ** Redistribution and use in source and binary forms, with or without
157 ** modification, are permitted provided that the following conditions
158 ** are met:
159 **
160 ** 1 Redistributions of source code must retain the above copyright
161 ** notice, this list of conditions and the following disclaimer.
162 **
163 ** 2 Redistributions in binary form must reproduce the above copyright
164 ** notice, this list of conditions and the following disclaimer in
165 ** the documentation and/or other materials provided with the
166 ** distribution.
167 **
168 ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
169 ** the International Astronomical Union nor the names of its
170 ** contributors may be used to endorse or promote products derived
171 ** from this software without specific prior written permission.
172 **
173 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
174 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
175 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
176 ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
177 ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
178 ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
179 ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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185 **
186 */
187