source: trunk/FACT++/erfa/src/s06.c@ 18348

Last change on this file since 18348 was 18348, checked in by tbretz, 9 years ago
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Line 
1#include "erfa.h"
2
3double eraS06(double date1, double date2, double x, double y)
4/*
5** - - - - - - -
6** e r a S 0 6
7** - - - - - - -
8**
9** The CIO locator s, positioning the Celestial Intermediate Origin on
10** the equator of the Celestial Intermediate Pole, given the CIP's X,Y
11** coordinates. Compatible with IAU 2006/2000A precession-nutation.
12**
13** Given:
14** date1,date2 double TT as a 2-part Julian Date (Note 1)
15** x,y double CIP coordinates (Note 3)
16**
17** Returned (function value):
18** double the CIO locator s in radians (Note 2)
19**
20** Notes:
21**
22** 1) The TT date date1+date2 is a Julian Date, apportioned in any
23** convenient way between the two arguments. For example,
24** JD(TT)=2450123.7 could be expressed in any of these ways,
25** among others:
26**
27** date1 date2
28**
29** 2450123.7 0.0 (JD method)
30** 2451545.0 -1421.3 (J2000 method)
31** 2400000.5 50123.2 (MJD method)
32** 2450123.5 0.2 (date & time method)
33**
34** The JD method is the most natural and convenient to use in
35** cases where the loss of several decimal digits of resolution
36** is acceptable. The J2000 method is best matched to the way
37** the argument is handled internally and will deliver the
38** optimum resolution. The MJD method and the date & time methods
39** are both good compromises between resolution and convenience.
40**
41** 2) The CIO locator s is the difference between the right ascensions
42** of the same point in two systems: the two systems are the GCRS
43** and the CIP,CIO, and the point is the ascending node of the
44** CIP equator. The quantity s remains below 0.1 arcsecond
45** throughout 1900-2100.
46**
47** 3) The series used to compute s is in fact for s+XY/2, where X and Y
48** are the x and y components of the CIP unit vector; this series
49** is more compact than a direct series for s would be. This
50** function requires X,Y to be supplied by the caller, who is
51** responsible for providing values that are consistent with the
52** supplied date.
53**
54** 4) The model is consistent with the "P03" precession (Capitaine et
55** al. 2003), adopted by IAU 2006 Resolution 1, 2006, and the
56** IAU 2000A nutation (with P03 adjustments).
57**
58** Called:
59** eraFal03 mean anomaly of the Moon
60** eraFalp03 mean anomaly of the Sun
61** eraFaf03 mean argument of the latitude of the Moon
62** eraFad03 mean elongation of the Moon from the Sun
63** eraFaom03 mean longitude of the Moon's ascending node
64** eraFave03 mean longitude of Venus
65** eraFae03 mean longitude of Earth
66** eraFapa03 general accumulated precession in longitude
67**
68** References:
69**
70** Capitaine, N., Wallace, P.T. & Chapront, J., 2003, Astron.
71** Astrophys. 432, 355
72**
73** McCarthy, D.D., Petit, G. (eds.) 2004, IERS Conventions (2003),
74** IERS Technical Note No. 32, BKG
75**
76** Copyright (C) 2013-2015, NumFOCUS Foundation.
77** Derived, with permission, from the SOFA library. See notes at end of file.
78*/
79{
80/* Time since J2000.0, in Julian centuries */
81 double t;
82
83/* Miscellaneous */
84 int i, j;
85 double a, w0, w1, w2, w3, w4, w5;
86
87/* Fundamental arguments */
88 double fa[8];
89
90/* Returned value */
91 double s;
92
93/* --------------------- */
94/* The series for s+XY/2 */
95/* --------------------- */
96
97 typedef struct {
98 int nfa[8]; /* coefficients of l,l',F,D,Om,LVe,LE,pA */
99 double s, c; /* sine and cosine coefficients */
100 } TERM;
101
102/* Polynomial coefficients */
103 static const double sp[] = {
104
105 /* 1-6 */
106 94.00e-6,
107 3808.65e-6,
108 -122.68e-6,
109 -72574.11e-6,
110 27.98e-6,
111 15.62e-6
112 };
113
114/* Terms of order t^0 */
115 static const TERM s0[] = {
116
117 /* 1-10 */
118 {{ 0, 0, 0, 0, 1, 0, 0, 0}, -2640.73e-6, 0.39e-6 },
119 {{ 0, 0, 0, 0, 2, 0, 0, 0}, -63.53e-6, 0.02e-6 },
120 {{ 0, 0, 2, -2, 3, 0, 0, 0}, -11.75e-6, -0.01e-6 },
121 {{ 0, 0, 2, -2, 1, 0, 0, 0}, -11.21e-6, -0.01e-6 },
122 {{ 0, 0, 2, -2, 2, 0, 0, 0}, 4.57e-6, 0.00e-6 },
123 {{ 0, 0, 2, 0, 3, 0, 0, 0}, -2.02e-6, 0.00e-6 },
124 {{ 0, 0, 2, 0, 1, 0, 0, 0}, -1.98e-6, 0.00e-6 },
125 {{ 0, 0, 0, 0, 3, 0, 0, 0}, 1.72e-6, 0.00e-6 },
126 {{ 0, 1, 0, 0, 1, 0, 0, 0}, 1.41e-6, 0.01e-6 },
127 {{ 0, 1, 0, 0, -1, 0, 0, 0}, 1.26e-6, 0.01e-6 },
128
129 /* 11-20 */
130 {{ 1, 0, 0, 0, -1, 0, 0, 0}, 0.63e-6, 0.00e-6 },
131 {{ 1, 0, 0, 0, 1, 0, 0, 0}, 0.63e-6, 0.00e-6 },
132 {{ 0, 1, 2, -2, 3, 0, 0, 0}, -0.46e-6, 0.00e-6 },
133 {{ 0, 1, 2, -2, 1, 0, 0, 0}, -0.45e-6, 0.00e-6 },
134 {{ 0, 0, 4, -4, 4, 0, 0, 0}, -0.36e-6, 0.00e-6 },
135 {{ 0, 0, 1, -1, 1, -8, 12, 0}, 0.24e-6, 0.12e-6 },
136 {{ 0, 0, 2, 0, 0, 0, 0, 0}, -0.32e-6, 0.00e-6 },
137 {{ 0, 0, 2, 0, 2, 0, 0, 0}, -0.28e-6, 0.00e-6 },
138 {{ 1, 0, 2, 0, 3, 0, 0, 0}, -0.27e-6, 0.00e-6 },
139 {{ 1, 0, 2, 0, 1, 0, 0, 0}, -0.26e-6, 0.00e-6 },
140
141 /* 21-30 */
142 {{ 0, 0, 2, -2, 0, 0, 0, 0}, 0.21e-6, 0.00e-6 },
143 {{ 0, 1, -2, 2, -3, 0, 0, 0}, -0.19e-6, 0.00e-6 },
144 {{ 0, 1, -2, 2, -1, 0, 0, 0}, -0.18e-6, 0.00e-6 },
145 {{ 0, 0, 0, 0, 0, 8,-13, -1}, 0.10e-6, -0.05e-6 },
146 {{ 0, 0, 0, 2, 0, 0, 0, 0}, -0.15e-6, 0.00e-6 },
147 {{ 2, 0, -2, 0, -1, 0, 0, 0}, 0.14e-6, 0.00e-6 },
148 {{ 0, 1, 2, -2, 2, 0, 0, 0}, 0.14e-6, 0.00e-6 },
149 {{ 1, 0, 0, -2, 1, 0, 0, 0}, -0.14e-6, 0.00e-6 },
150 {{ 1, 0, 0, -2, -1, 0, 0, 0}, -0.14e-6, 0.00e-6 },
151 {{ 0, 0, 4, -2, 4, 0, 0, 0}, -0.13e-6, 0.00e-6 },
152
153 /* 31-33 */
154 {{ 0, 0, 2, -2, 4, 0, 0, 0}, 0.11e-6, 0.00e-6 },
155 {{ 1, 0, -2, 0, -3, 0, 0, 0}, -0.11e-6, 0.00e-6 },
156 {{ 1, 0, -2, 0, -1, 0, 0, 0}, -0.11e-6, 0.00e-6 }
157 };
158
159/* Terms of order t^1 */
160 static const TERM s1[] = {
161
162 /* 1 - 3 */
163 {{ 0, 0, 0, 0, 2, 0, 0, 0}, -0.07e-6, 3.57e-6 },
164 {{ 0, 0, 0, 0, 1, 0, 0, 0}, 1.73e-6, -0.03e-6 },
165 {{ 0, 0, 2, -2, 3, 0, 0, 0}, 0.00e-6, 0.48e-6 }
166 };
167
168/* Terms of order t^2 */
169 static const TERM s2[] = {
170
171 /* 1-10 */
172 {{ 0, 0, 0, 0, 1, 0, 0, 0}, 743.52e-6, -0.17e-6 },
173 {{ 0, 0, 2, -2, 2, 0, 0, 0}, 56.91e-6, 0.06e-6 },
174 {{ 0, 0, 2, 0, 2, 0, 0, 0}, 9.84e-6, -0.01e-6 },
175 {{ 0, 0, 0, 0, 2, 0, 0, 0}, -8.85e-6, 0.01e-6 },
176 {{ 0, 1, 0, 0, 0, 0, 0, 0}, -6.38e-6, -0.05e-6 },
177 {{ 1, 0, 0, 0, 0, 0, 0, 0}, -3.07e-6, 0.00e-6 },
178 {{ 0, 1, 2, -2, 2, 0, 0, 0}, 2.23e-6, 0.00e-6 },
179 {{ 0, 0, 2, 0, 1, 0, 0, 0}, 1.67e-6, 0.00e-6 },
180 {{ 1, 0, 2, 0, 2, 0, 0, 0}, 1.30e-6, 0.00e-6 },
181 {{ 0, 1, -2, 2, -2, 0, 0, 0}, 0.93e-6, 0.00e-6 },
182
183 /* 11-20 */
184 {{ 1, 0, 0, -2, 0, 0, 0, 0}, 0.68e-6, 0.00e-6 },
185 {{ 0, 0, 2, -2, 1, 0, 0, 0}, -0.55e-6, 0.00e-6 },
186 {{ 1, 0, -2, 0, -2, 0, 0, 0}, 0.53e-6, 0.00e-6 },
187 {{ 0, 0, 0, 2, 0, 0, 0, 0}, -0.27e-6, 0.00e-6 },
188 {{ 1, 0, 0, 0, 1, 0, 0, 0}, -0.27e-6, 0.00e-6 },
189 {{ 1, 0, -2, -2, -2, 0, 0, 0}, -0.26e-6, 0.00e-6 },
190 {{ 1, 0, 0, 0, -1, 0, 0, 0}, -0.25e-6, 0.00e-6 },
191 {{ 1, 0, 2, 0, 1, 0, 0, 0}, 0.22e-6, 0.00e-6 },
192 {{ 2, 0, 0, -2, 0, 0, 0, 0}, -0.21e-6, 0.00e-6 },
193 {{ 2, 0, -2, 0, -1, 0, 0, 0}, 0.20e-6, 0.00e-6 },
194
195 /* 21-25 */
196 {{ 0, 0, 2, 2, 2, 0, 0, 0}, 0.17e-6, 0.00e-6 },
197 {{ 2, 0, 2, 0, 2, 0, 0, 0}, 0.13e-6, 0.00e-6 },
198 {{ 2, 0, 0, 0, 0, 0, 0, 0}, -0.13e-6, 0.00e-6 },
199 {{ 1, 0, 2, -2, 2, 0, 0, 0}, -0.12e-6, 0.00e-6 },
200 {{ 0, 0, 2, 0, 0, 0, 0, 0}, -0.11e-6, 0.00e-6 }
201 };
202
203/* Terms of order t^3 */
204 static const TERM s3[] = {
205
206 /* 1-4 */
207 {{ 0, 0, 0, 0, 1, 0, 0, 0}, 0.30e-6, -23.42e-6 },
208 {{ 0, 0, 2, -2, 2, 0, 0, 0}, -0.03e-6, -1.46e-6 },
209 {{ 0, 0, 2, 0, 2, 0, 0, 0}, -0.01e-6, -0.25e-6 },
210 {{ 0, 0, 0, 0, 2, 0, 0, 0}, 0.00e-6, 0.23e-6 }
211 };
212
213/* Terms of order t^4 */
214 static const TERM s4[] = {
215
216 /* 1-1 */
217 {{ 0, 0, 0, 0, 1, 0, 0, 0}, -0.26e-6, -0.01e-6 }
218 };
219
220/* Number of terms in the series */
221 static const int NS0 = (int) (sizeof s0 / sizeof (TERM));
222 static const int NS1 = (int) (sizeof s1 / sizeof (TERM));
223 static const int NS2 = (int) (sizeof s2 / sizeof (TERM));
224 static const int NS3 = (int) (sizeof s3 / sizeof (TERM));
225 static const int NS4 = (int) (sizeof s4 / sizeof (TERM));
226
227/*--------------------------------------------------------------------*/
228
229/* Interval between fundamental epoch J2000.0 and current date (JC). */
230 t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
231
232/* Fundamental Arguments (from IERS Conventions 2003) */
233
234/* Mean anomaly of the Moon. */
235 fa[0] = eraFal03(t);
236
237/* Mean anomaly of the Sun. */
238 fa[1] = eraFalp03(t);
239
240/* Mean longitude of the Moon minus that of the ascending node. */
241 fa[2] = eraFaf03(t);
242
243/* Mean elongation of the Moon from the Sun. */
244 fa[3] = eraFad03(t);
245
246/* Mean longitude of the ascending node of the Moon. */
247 fa[4] = eraFaom03(t);
248
249/* Mean longitude of Venus. */
250 fa[5] = eraFave03(t);
251
252/* Mean longitude of Earth. */
253 fa[6] = eraFae03(t);
254
255/* General precession in longitude. */
256 fa[7] = eraFapa03(t);
257
258/* Evaluate s. */
259 w0 = sp[0];
260 w1 = sp[1];
261 w2 = sp[2];
262 w3 = sp[3];
263 w4 = sp[4];
264 w5 = sp[5];
265
266 for (i = NS0-1; i >= 0; i--) {
267 a = 0.0;
268 for (j = 0; j < 8; j++) {
269 a += (double)s0[i].nfa[j] * fa[j];
270 }
271 w0 += s0[i].s * sin(a) + s0[i].c * cos(a);
272 }
273
274 for (i = NS1-1; i >= 0; i--) {
275 a = 0.0;
276 for (j = 0; j < 8; j++) {
277 a += (double)s1[i].nfa[j] * fa[j];
278 }
279 w1 += s1[i].s * sin(a) + s1[i].c * cos(a);
280 }
281
282 for (i = NS2-1; i >= 0; i--) {
283 a = 0.0;
284 for (j = 0; j < 8; j++) {
285 a += (double)s2[i].nfa[j] * fa[j];
286 }
287 w2 += s2[i].s * sin(a) + s2[i].c * cos(a);
288 }
289
290 for (i = NS3-1; i >= 0; i--) {
291 a = 0.0;
292 for (j = 0; j < 8; j++) {
293 a += (double)s3[i].nfa[j] * fa[j];
294 }
295 w3 += s3[i].s * sin(a) + s3[i].c * cos(a);
296 }
297
298 for (i = NS4-1; i >= 0; i--) {
299 a = 0.0;
300 for (j = 0; j < 8; j++) {
301 a += (double)s4[i].nfa[j] * fa[j];
302 }
303 w4 += s4[i].s * sin(a) + s4[i].c * cos(a);
304 }
305
306 s = (w0 +
307 (w1 +
308 (w2 +
309 (w3 +
310 (w4 +
311 w5 * t) * t) * t) * t) * t) * ERFA_DAS2R - x*y/2.0;
312
313 return s;
314
315}
316/*----------------------------------------------------------------------
317**
318**
319** Copyright (C) 2013-2015, NumFOCUS Foundation.
320** All rights reserved.
321**
322** This library is derived, with permission, from the International
323** Astronomical Union's "Standards of Fundamental Astronomy" library,
324** available from http://www.iausofa.org.
325**
326** The ERFA version is intended to retain identical functionality to
327** the SOFA library, but made distinct through different function and
328** file names, as set out in the SOFA license conditions. The SOFA
329** original has a role as a reference standard for the IAU and IERS,
330** and consequently redistribution is permitted only in its unaltered
331** state. The ERFA version is not subject to this restriction and
332** therefore can be included in distributions which do not support the
333** concept of "read only" software.
334**
335** Although the intent is to replicate the SOFA API (other than
336** replacement of prefix names) and results (with the exception of
337** bugs; any that are discovered will be fixed), SOFA is not
338** responsible for any errors found in this version of the library.
339**
340** If you wish to acknowledge the SOFA heritage, please acknowledge
341** that you are using a library derived from SOFA, rather than SOFA
342** itself.
343**
344**
345** TERMS AND CONDITIONS
346**
347** Redistribution and use in source and binary forms, with or without
348** modification, are permitted provided that the following conditions
349** are met:
350**
351** 1 Redistributions of source code must retain the above copyright
352** notice, this list of conditions and the following disclaimer.
353**
354** 2 Redistributions in binary form must reproduce the above copyright
355** notice, this list of conditions and the following disclaimer in
356** the documentation and/or other materials provided with the
357** distribution.
358**
359** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
360** the International Astronomical Union nor the names of its
361** contributors may be used to endorse or promote products derived
362** from this software without specific prior written permission.
363**
364** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
365** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
366** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
367** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
368** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
369** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
370** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
371** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
372** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
373** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
374** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
375** POSSIBILITY OF SUCH DAMAGE.
376**
377*/
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