source: trunk/FACT++/erfa/src/s00.c@ 19128

Last change on this file since 19128 was 18921, checked in by tbretz, 7 years ago
Updated to ERFA 1.4.0
File size: 13.8 KB
Line 
1#include "erfa.h"
2
3double eraS00(double date1, double date2, double x, double y)
4/*
5** - - - - - - -
6** e r a S 0 0
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 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 IAU 2000A precession-nutation.
55**
56** Called:
57** eraFal03 mean anomaly of the Moon
58** eraFalp03 mean anomaly of the Sun
59** eraFaf03 mean argument of the latitude of the Moon
60** eraFad03 mean elongation of the Moon from the Sun
61** eraFaom03 mean longitude of the Moon's ascending node
62** eraFave03 mean longitude of Venus
63** eraFae03 mean longitude of Earth
64** eraFapa03 general accumulated precession in longitude
65**
66** References:
67**
68** Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
69** "Expressions for the Celestial Intermediate Pole and Celestial
70** Ephemeris Origin consistent with the IAU 2000A precession-
71** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
72**
73** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
74** intermediate origin" (CIO) by IAU 2006 Resolution 2.
75**
76** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
77** IERS Technical Note No. 32, BKG (2004)
78**
79** Copyright (C) 2013-2017, NumFOCUS Foundation.
80** Derived, with permission, from the SOFA library. See notes at end of file.
81*/
82{
83/* Time since J2000.0, in Julian centuries */
84 double t;
85
86/* Miscellaneous */
87 int i, j;
88 double a, w0, w1, w2, w3, w4, w5;
89
90/* Fundamental arguments */
91 double fa[8];
92
93/* Returned value */
94 double s;
95
96/* --------------------- */
97/* The series for s+XY/2 */
98/* --------------------- */
99
100 typedef struct {
101 int nfa[8]; /* coefficients of l,l',F,D,Om,LVe,LE,pA */
102 double s, c; /* sine and cosine coefficients */
103 } TERM;
104
105/* Polynomial coefficients */
106 static const double sp[] = {
107
108 /* 1-6 */
109 94.00e-6,
110 3808.35e-6,
111 -119.94e-6,
112 -72574.09e-6,
113 27.70e-6,
114 15.61e-6
115 };
116
117/* Terms of order t^0 */
118 static const TERM s0[] = {
119
120 /* 1-10 */
121 {{ 0, 0, 0, 0, 1, 0, 0, 0}, -2640.73e-6, 0.39e-6 },
122 {{ 0, 0, 0, 0, 2, 0, 0, 0}, -63.53e-6, 0.02e-6 },
123 {{ 0, 0, 2, -2, 3, 0, 0, 0}, -11.75e-6, -0.01e-6 },
124 {{ 0, 0, 2, -2, 1, 0, 0, 0}, -11.21e-6, -0.01e-6 },
125 {{ 0, 0, 2, -2, 2, 0, 0, 0}, 4.57e-6, 0.00e-6 },
126 {{ 0, 0, 2, 0, 3, 0, 0, 0}, -2.02e-6, 0.00e-6 },
127 {{ 0, 0, 2, 0, 1, 0, 0, 0}, -1.98e-6, 0.00e-6 },
128 {{ 0, 0, 0, 0, 3, 0, 0, 0}, 1.72e-6, 0.00e-6 },
129 {{ 0, 1, 0, 0, 1, 0, 0, 0}, 1.41e-6, 0.01e-6 },
130 {{ 0, 1, 0, 0, -1, 0, 0, 0}, 1.26e-6, 0.01e-6 },
131
132 /* 11-20 */
133 {{ 1, 0, 0, 0, -1, 0, 0, 0}, 0.63e-6, 0.00e-6 },
134 {{ 1, 0, 0, 0, 1, 0, 0, 0}, 0.63e-6, 0.00e-6 },
135 {{ 0, 1, 2, -2, 3, 0, 0, 0}, -0.46e-6, 0.00e-6 },
136 {{ 0, 1, 2, -2, 1, 0, 0, 0}, -0.45e-6, 0.00e-6 },
137 {{ 0, 0, 4, -4, 4, 0, 0, 0}, -0.36e-6, 0.00e-6 },
138 {{ 0, 0, 1, -1, 1, -8, 12, 0}, 0.24e-6, 0.12e-6 },
139 {{ 0, 0, 2, 0, 0, 0, 0, 0}, -0.32e-6, 0.00e-6 },
140 {{ 0, 0, 2, 0, 2, 0, 0, 0}, -0.28e-6, 0.00e-6 },
141 {{ 1, 0, 2, 0, 3, 0, 0, 0}, -0.27e-6, 0.00e-6 },
142 {{ 1, 0, 2, 0, 1, 0, 0, 0}, -0.26e-6, 0.00e-6 },
143
144 /* 21-30 */
145 {{ 0, 0, 2, -2, 0, 0, 0, 0}, 0.21e-6, 0.00e-6 },
146 {{ 0, 1, -2, 2, -3, 0, 0, 0}, -0.19e-6, 0.00e-6 },
147 {{ 0, 1, -2, 2, -1, 0, 0, 0}, -0.18e-6, 0.00e-6 },
148 {{ 0, 0, 0, 0, 0, 8,-13, -1}, 0.10e-6, -0.05e-6 },
149 {{ 0, 0, 0, 2, 0, 0, 0, 0}, -0.15e-6, 0.00e-6 },
150 {{ 2, 0, -2, 0, -1, 0, 0, 0}, 0.14e-6, 0.00e-6 },
151 {{ 0, 1, 2, -2, 2, 0, 0, 0}, 0.14e-6, 0.00e-6 },
152 {{ 1, 0, 0, -2, 1, 0, 0, 0}, -0.14e-6, 0.00e-6 },
153 {{ 1, 0, 0, -2, -1, 0, 0, 0}, -0.14e-6, 0.00e-6 },
154 {{ 0, 0, 4, -2, 4, 0, 0, 0}, -0.13e-6, 0.00e-6 },
155
156 /* 31-33 */
157 {{ 0, 0, 2, -2, 4, 0, 0, 0}, 0.11e-6, 0.00e-6 },
158 {{ 1, 0, -2, 0, -3, 0, 0, 0}, -0.11e-6, 0.00e-6 },
159 {{ 1, 0, -2, 0, -1, 0, 0, 0}, -0.11e-6, 0.00e-6 }
160 };
161
162/* Terms of order t^1 */
163 static const TERM s1[] ={
164
165 /* 1-3 */
166 {{ 0, 0, 0, 0, 2, 0, 0, 0}, -0.07e-6, 3.57e-6 },
167 {{ 0, 0, 0, 0, 1, 0, 0, 0}, 1.71e-6, -0.03e-6 },
168 {{ 0, 0, 2, -2, 3, 0, 0, 0}, 0.00e-6, 0.48e-6 }
169 };
170
171/* Terms of order t^2 */
172 static const TERM s2[] ={
173
174 /* 1-10 */
175 {{ 0, 0, 0, 0, 1, 0, 0, 0}, 743.53e-6, -0.17e-6 },
176 {{ 0, 0, 2, -2, 2, 0, 0, 0}, 56.91e-6, 0.06e-6 },
177 {{ 0, 0, 2, 0, 2, 0, 0, 0}, 9.84e-6, -0.01e-6 },
178 {{ 0, 0, 0, 0, 2, 0, 0, 0}, -8.85e-6, 0.01e-6 },
179 {{ 0, 1, 0, 0, 0, 0, 0, 0}, -6.38e-6, -0.05e-6 },
180 {{ 1, 0, 0, 0, 0, 0, 0, 0}, -3.07e-6, 0.00e-6 },
181 {{ 0, 1, 2, -2, 2, 0, 0, 0}, 2.23e-6, 0.00e-6 },
182 {{ 0, 0, 2, 0, 1, 0, 0, 0}, 1.67e-6, 0.00e-6 },
183 {{ 1, 0, 2, 0, 2, 0, 0, 0}, 1.30e-6, 0.00e-6 },
184 {{ 0, 1, -2, 2, -2, 0, 0, 0}, 0.93e-6, 0.00e-6 },
185
186 /* 11-20 */
187 {{ 1, 0, 0, -2, 0, 0, 0, 0}, 0.68e-6, 0.00e-6 },
188 {{ 0, 0, 2, -2, 1, 0, 0, 0}, -0.55e-6, 0.00e-6 },
189 {{ 1, 0, -2, 0, -2, 0, 0, 0}, 0.53e-6, 0.00e-6 },
190 {{ 0, 0, 0, 2, 0, 0, 0, 0}, -0.27e-6, 0.00e-6 },
191 {{ 1, 0, 0, 0, 1, 0, 0, 0}, -0.27e-6, 0.00e-6 },
192 {{ 1, 0, -2, -2, -2, 0, 0, 0}, -0.26e-6, 0.00e-6 },
193 {{ 1, 0, 0, 0, -1, 0, 0, 0}, -0.25e-6, 0.00e-6 },
194 {{ 1, 0, 2, 0, 1, 0, 0, 0}, 0.22e-6, 0.00e-6 },
195 {{ 2, 0, 0, -2, 0, 0, 0, 0}, -0.21e-6, 0.00e-6 },
196 {{ 2, 0, -2, 0, -1, 0, 0, 0}, 0.20e-6, 0.00e-6 },
197
198 /* 21-25 */
199 {{ 0, 0, 2, 2, 2, 0, 0, 0}, 0.17e-6, 0.00e-6 },
200 {{ 2, 0, 2, 0, 2, 0, 0, 0}, 0.13e-6, 0.00e-6 },
201 {{ 2, 0, 0, 0, 0, 0, 0, 0}, -0.13e-6, 0.00e-6 },
202 {{ 1, 0, 2, -2, 2, 0, 0, 0}, -0.12e-6, 0.00e-6 },
203 {{ 0, 0, 2, 0, 0, 0, 0, 0}, -0.11e-6, 0.00e-6 }
204 };
205
206/* Terms of order t^3 */
207 static const TERM s3[] ={
208
209 /* 1-4 */
210 {{ 0, 0, 0, 0, 1, 0, 0, 0}, 0.30e-6, -23.51e-6 },
211 {{ 0, 0, 2, -2, 2, 0, 0, 0}, -0.03e-6, -1.39e-6 },
212 {{ 0, 0, 2, 0, 2, 0, 0, 0}, -0.01e-6, -0.24e-6 },
213 {{ 0, 0, 0, 0, 2, 0, 0, 0}, 0.00e-6, 0.22e-6 }
214 };
215
216/* Terms of order t^4 */
217 static const TERM s4[] ={
218
219 /* 1-1 */
220 {{ 0, 0, 0, 0, 1, 0, 0, 0}, -0.26e-6, -0.01e-6 }
221 };
222
223/* Number of terms in the series */
224 const int NS0 = (int) (sizeof s0 / sizeof (TERM));
225 const int NS1 = (int) (sizeof s1 / sizeof (TERM));
226 const int NS2 = (int) (sizeof s2 / sizeof (TERM));
227 const int NS3 = (int) (sizeof s3 / sizeof (TERM));
228 const int NS4 = (int) (sizeof s4 / sizeof (TERM));
229
230/*--------------------------------------------------------------------*/
231
232/* Interval between fundamental epoch J2000.0 and current date (JC). */
233 t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
234
235/* Fundamental Arguments (from IERS Conventions 2003) */
236
237/* Mean anomaly of the Moon. */
238 fa[0] = eraFal03(t);
239
240/* Mean anomaly of the Sun. */
241 fa[1] = eraFalp03(t);
242
243/* Mean longitude of the Moon minus that of the ascending node. */
244 fa[2] = eraFaf03(t);
245
246/* Mean elongation of the Moon from the Sun. */
247 fa[3] = eraFad03(t);
248
249/* Mean longitude of the ascending node of the Moon. */
250 fa[4] = eraFaom03(t);
251
252/* Mean longitude of Venus. */
253 fa[5] = eraFave03(t);
254
255/* Mean longitude of Earth. */
256 fa[6] = eraFae03(t);
257
258/* General precession in longitude. */
259 fa[7] = eraFapa03(t);
260
261/* Evaluate s. */
262 w0 = sp[0];
263 w1 = sp[1];
264 w2 = sp[2];
265 w3 = sp[3];
266 w4 = sp[4];
267 w5 = sp[5];
268
269 for (i = NS0-1; i >= 0; i--) {
270 a = 0.0;
271 for (j = 0; j < 8; j++) {
272 a += (double)s0[i].nfa[j] * fa[j];
273 }
274 w0 += s0[i].s * sin(a) + s0[i].c * cos(a);
275 }
276
277 for (i = NS1-1; i >= 0; i--) {
278 a = 0.0;
279 for (j = 0; j < 8; j++) {
280 a += (double)s1[i].nfa[j] * fa[j];
281 }
282 w1 += s1[i].s * sin(a) + s1[i].c * cos(a);
283 }
284
285 for (i = NS2-1; i >= 0; i--) {
286 a = 0.0;
287 for (j = 0; j < 8; j++) {
288 a += (double)s2[i].nfa[j] * fa[j];
289 }
290 w2 += s2[i].s * sin(a) + s2[i].c * cos(a);
291 }
292
293 for (i = NS3-1; i >= 0; i--) {
294 a = 0.0;
295 for (j = 0; j < 8; j++) {
296 a += (double)s3[i].nfa[j] * fa[j];
297 }
298 w3 += s3[i].s * sin(a) + s3[i].c * cos(a);
299 }
300
301 for (i = NS4-1; i >= 0; i--) {
302 a = 0.0;
303 for (j = 0; j < 8; j++) {
304 a += (double)s4[i].nfa[j] * fa[j];
305 }
306 w4 += s4[i].s * sin(a) + s4[i].c * cos(a);
307 }
308
309 s = (w0 +
310 (w1 +
311 (w2 +
312 (w3 +
313 (w4 +
314 w5 * t) * t) * t) * t) * t) * ERFA_DAS2R - x*y/2.0;
315
316 return s;
317
318}
319/*----------------------------------------------------------------------
320**
321**
322** Copyright (C) 2013-2017, NumFOCUS Foundation.
323** All rights reserved.
324**
325** This library is derived, with permission, from the International
326** Astronomical Union's "Standards of Fundamental Astronomy" library,
327** available from http://www.iausofa.org.
328**
329** The ERFA version is intended to retain identical functionality to
330** the SOFA library, but made distinct through different function and
331** file names, as set out in the SOFA license conditions. The SOFA
332** original has a role as a reference standard for the IAU and IERS,
333** and consequently redistribution is permitted only in its unaltered
334** state. The ERFA version is not subject to this restriction and
335** therefore can be included in distributions which do not support the
336** concept of "read only" software.
337**
338** Although the intent is to replicate the SOFA API (other than
339** replacement of prefix names) and results (with the exception of
340** bugs; any that are discovered will be fixed), SOFA is not
341** responsible for any errors found in this version of the library.
342**
343** If you wish to acknowledge the SOFA heritage, please acknowledge
344** that you are using a library derived from SOFA, rather than SOFA
345** itself.
346**
347**
348** TERMS AND CONDITIONS
349**
350** Redistribution and use in source and binary forms, with or without
351** modification, are permitted provided that the following conditions
352** are met:
353**
354** 1 Redistributions of source code must retain the above copyright
355** notice, this list of conditions and the following disclaimer.
356**
357** 2 Redistributions in binary form must reproduce the above copyright
358** notice, this list of conditions and the following disclaimer in
359** the documentation and/or other materials provided with the
360** distribution.
361**
362** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
363** the International Astronomical Union nor the names of its
364** contributors may be used to endorse or promote products derived
365** from this software without specific prior written permission.
366**
367** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
368** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
369** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
370** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
371** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
372** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
373** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
374** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
375** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
376** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
377** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
378** POSSIBILITY OF SUCH DAMAGE.
379**
380*/
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