source: trunk/FACT++/erfa/src/aticq.c@ 19594

Last change on this file since 19594 was 18921, checked in by tbretz, 8 years ago
Updated to ERFA 1.4.0
File size: 7.1 KB
Line 
1#include "erfa.h"
2
3void eraAticq(double ri, double di, eraASTROM *astrom,
4 double *rc, double *dc)
5/*
6** - - - - - - - - -
7** e r a A t i c q
8** - - - - - - - - -
9**
10** Quick CIRS RA,Dec to ICRS astrometric place, given the star-
11** independent astrometry parameters.
12**
13** Use of this function is appropriate when efficiency is important and
14** where many star positions are all to be transformed for one date.
15** The star-independent astrometry parameters can be obtained by
16** calling one of the functions eraApci[13], eraApcg[13], eraApco[13]
17** or eraApcs[13].
18**
19** Given:
20** ri,di double CIRS RA,Dec (radians)
21** astrom eraASTROM* star-independent astrometry parameters:
22** pmt double PM time interval (SSB, Julian years)
23** eb double[3] SSB to observer (vector, au)
24** eh double[3] Sun to observer (unit vector)
25** em double distance from Sun to observer (au)
26** v double[3] barycentric observer velocity (vector, c)
27** bm1 double sqrt(1-|v|^2): reciprocal of Lorenz factor
28** bpn double[3][3] bias-precession-nutation matrix
29** along double longitude + s' (radians)
30** xpl double polar motion xp wrt local meridian (radians)
31** ypl double polar motion yp wrt local meridian (radians)
32** sphi double sine of geodetic latitude
33** cphi double cosine of geodetic latitude
34** diurab double magnitude of diurnal aberration vector
35** eral double "local" Earth rotation angle (radians)
36** refa double refraction constant A (radians)
37** refb double refraction constant B (radians)
38**
39** Returned:
40** rc,dc double ICRS astrometric RA,Dec (radians)
41**
42** Notes:
43**
44** 1) Only the Sun is taken into account in the light deflection
45** correction.
46**
47** 2) Iterative techniques are used for the aberration and light
48** deflection corrections so that the functions eraAtic13 (or
49** eraAticq) and eraAtci13 (or eraAtciq) are accurate inverses;
50** even at the edge of the Sun's disk the discrepancy is only about
51** 1 nanoarcsecond.
52**
53** Called:
54** eraS2c spherical coordinates to unit vector
55** eraTrxp product of transpose of r-matrix and p-vector
56** eraZp zero p-vector
57** eraAb stellar aberration
58** eraLdsun light deflection by the Sun
59** eraC2s p-vector to spherical
60** eraAnp normalize angle into range +/- pi
61**
62** Copyright (C) 2013-2017, NumFOCUS Foundation.
63** Derived, with permission, from the SOFA library. See notes at end of file.
64*/
65{
66 int j, i;
67 double pi[3], ppr[3], pnat[3], pco[3], w, d[3], before[3], r2, r,
68 after[3];
69
70
71/* CIRS RA,Dec to Cartesian. */
72 eraS2c(ri, di, pi);
73
74/* Bias-precession-nutation, giving GCRS proper direction. */
75 eraTrxp(astrom->bpn, pi, ppr);
76
77/* Aberration, giving GCRS natural direction. */
78 eraZp(d);
79 for (j = 0; j < 2; j++) {
80 r2 = 0.0;
81 for (i = 0; i < 3; i++) {
82 w = ppr[i] - d[i];
83 before[i] = w;
84 r2 += w*w;
85 }
86 r = sqrt(r2);
87 for (i = 0; i < 3; i++) {
88 before[i] /= r;
89 }
90 eraAb(before, astrom->v, astrom->em, astrom->bm1, after);
91 r2 = 0.0;
92 for (i = 0; i < 3; i++) {
93 d[i] = after[i] - before[i];
94 w = ppr[i] - d[i];
95 pnat[i] = w;
96 r2 += w*w;
97 }
98 r = sqrt(r2);
99 for (i = 0; i < 3; i++) {
100 pnat[i] /= r;
101 }
102 }
103
104/* Light deflection by the Sun, giving BCRS coordinate direction. */
105 eraZp(d);
106 for (j = 0; j < 5; j++) {
107 r2 = 0.0;
108 for (i = 0; i < 3; i++) {
109 w = pnat[i] - d[i];
110 before[i] = w;
111 r2 += w*w;
112 }
113 r = sqrt(r2);
114 for (i = 0; i < 3; i++) {
115 before[i] /= r;
116 }
117 eraLdsun(before, astrom->eh, astrom->em, after);
118 r2 = 0.0;
119 for (i = 0; i < 3; i++) {
120 d[i] = after[i] - before[i];
121 w = pnat[i] - d[i];
122 pco[i] = w;
123 r2 += w*w;
124 }
125 r = sqrt(r2);
126 for (i = 0; i < 3; i++) {
127 pco[i] /= r;
128 }
129 }
130
131/* ICRS astrometric RA,Dec. */
132 eraC2s(pco, &w, dc);
133 *rc = eraAnp(w);
134
135/* Finished. */
136
137}
138/*----------------------------------------------------------------------
139**
140**
141** Copyright (C) 2013-2017, NumFOCUS Foundation.
142** All rights reserved.
143**
144** This library is derived, with permission, from the International
145** Astronomical Union's "Standards of Fundamental Astronomy" library,
146** available from http://www.iausofa.org.
147**
148** The ERFA version is intended to retain identical functionality to
149** the SOFA library, but made distinct through different function and
150** file names, as set out in the SOFA license conditions. The SOFA
151** original has a role as a reference standard for the IAU and IERS,
152** and consequently redistribution is permitted only in its unaltered
153** state. The ERFA version is not subject to this restriction and
154** therefore can be included in distributions which do not support the
155** concept of "read only" software.
156**
157** Although the intent is to replicate the SOFA API (other than
158** replacement of prefix names) and results (with the exception of
159** bugs; any that are discovered will be fixed), SOFA is not
160** responsible for any errors found in this version of the library.
161**
162** If you wish to acknowledge the SOFA heritage, please acknowledge
163** that you are using a library derived from SOFA, rather than SOFA
164** itself.
165**
166**
167** TERMS AND CONDITIONS
168**
169** Redistribution and use in source and binary forms, with or without
170** modification, are permitted provided that the following conditions
171** are met:
172**
173** 1 Redistributions of source code must retain the above copyright
174** notice, this list of conditions and the following disclaimer.
175**
176** 2 Redistributions in binary form must reproduce the above copyright
177** notice, this list of conditions and the following disclaimer in
178** the documentation and/or other materials provided with the
179** distribution.
180**
181** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
182** the International Astronomical Union nor the names of its
183** contributors may be used to endorse or promote products derived
184** from this software without specific prior written permission.
185**
186** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
187** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
188** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
189** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
190** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
191** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
192** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
193** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
194** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
195** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
196** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
197** POSSIBILITY OF SUCH DAMAGE.
198**
199*/
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