source: branches/FACT++_lidctrl_usb/erfa/src/aper.c@ 19675

Last change on this file since 19675 was 18711, checked in by tbretz, 9 years ago
Updated to ERFA 1.3.0 (no relevant code change except the leap second at the beginning of 2017)
File size: 6.7 KB
Line 
1#include "erfa.h"
2
3void eraAper(double theta, eraASTROM *astrom)
4/*
5** - - - - - - - -
6** e r a A p e r
7** - - - - - - - -
8**
9** In the star-independent astrometry parameters, update only the
10** Earth rotation angle, supplied by the caller explicitly.
11**
12** Given:
13** theta double Earth rotation angle (radians, Note 2)
14** astrom eraASTROM* star-independent astrometry parameters:
15** pmt double not used
16** eb double[3] not used
17** eh double[3] not used
18** em double not used
19** v double[3] not used
20** bm1 double not used
21** bpn double[3][3] not used
22** along double longitude + s' (radians)
23** xpl double not used
24** ypl double not used
25** sphi double not used
26** cphi double not used
27** diurab double not used
28** eral double not used
29** refa double not used
30** refb double not used
31**
32** Returned:
33** astrom eraASTROM* star-independent astrometry parameters:
34** pmt double unchanged
35** eb double[3] unchanged
36** eh double[3] unchanged
37** em double unchanged
38** v double[3] unchanged
39** bm1 double unchanged
40** bpn double[3][3] unchanged
41** along double unchanged
42** xpl double unchanged
43** ypl double unchanged
44** sphi double unchanged
45** cphi double unchanged
46** diurab double unchanged
47** eral double "local" Earth rotation angle (radians)
48** refa double unchanged
49** refb double unchanged
50**
51** Notes:
52**
53** 1) This function exists to enable sidereal-tracking applications to
54** avoid wasteful recomputation of the bulk of the astrometry
55** parameters: only the Earth rotation is updated.
56**
57** 2) For targets expressed as equinox based positions, such as
58** classical geocentric apparent (RA,Dec), the supplied theta can be
59** Greenwich apparent sidereal time rather than Earth rotation
60** angle.
61**
62** 3) The function eraAper13 can be used instead of the present
63** function, and starts from UT1 rather than ERA itself.
64**
65** 4) This is one of several functions that inserts into the astrom
66** structure star-independent parameters needed for the chain of
67** astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed.
68**
69** The various functions support different classes of observer and
70** portions of the transformation chain:
71**
72** functions observer transformation
73**
74** eraApcg eraApcg13 geocentric ICRS <-> GCRS
75** eraApci eraApci13 terrestrial ICRS <-> CIRS
76** eraApco eraApco13 terrestrial ICRS <-> observed
77** eraApcs eraApcs13 space ICRS <-> GCRS
78** eraAper eraAper13 terrestrial update Earth rotation
79** eraApio eraApio13 terrestrial CIRS <-> observed
80**
81** Those with names ending in "13" use contemporary ERFA models to
82** compute the various ephemerides. The others accept ephemerides
83** supplied by the caller.
84**
85** The transformation from ICRS to GCRS covers space motion,
86** parallax, light deflection, and aberration. From GCRS to CIRS
87** comprises frame bias and precession-nutation. From CIRS to
88** observed takes account of Earth rotation, polar motion, diurnal
89** aberration and parallax (unless subsumed into the ICRS <-> GCRS
90** transformation), and atmospheric refraction.
91**
92** Copyright (C) 2013-2016, NumFOCUS Foundation.
93** Derived, with permission, from the SOFA library. See notes at end of file.
94*/
95{
96 astrom->eral = theta + astrom->along;
97
98/* Finished. */
99
100}
101/*----------------------------------------------------------------------
102**
103**
104** Copyright (C) 2013-2016, NumFOCUS Foundation.
105** All rights reserved.
106**
107** This library is derived, with permission, from the International
108** Astronomical Union's "Standards of Fundamental Astronomy" library,
109** available from http://www.iausofa.org.
110**
111** The ERFA version is intended to retain identical functionality to
112** the SOFA library, but made distinct through different function and
113** file names, as set out in the SOFA license conditions. The SOFA
114** original has a role as a reference standard for the IAU and IERS,
115** and consequently redistribution is permitted only in its unaltered
116** state. The ERFA version is not subject to this restriction and
117** therefore can be included in distributions which do not support the
118** concept of "read only" software.
119**
120** Although the intent is to replicate the SOFA API (other than
121** replacement of prefix names) and results (with the exception of
122** bugs; any that are discovered will be fixed), SOFA is not
123** responsible for any errors found in this version of the library.
124**
125** If you wish to acknowledge the SOFA heritage, please acknowledge
126** that you are using a library derived from SOFA, rather than SOFA
127** itself.
128**
129**
130** TERMS AND CONDITIONS
131**
132** Redistribution and use in source and binary forms, with or without
133** modification, are permitted provided that the following conditions
134** are met:
135**
136** 1 Redistributions of source code must retain the above copyright
137** notice, this list of conditions and the following disclaimer.
138**
139** 2 Redistributions in binary form must reproduce the above copyright
140** notice, this list of conditions and the following disclaimer in
141** the documentation and/or other materials provided with the
142** distribution.
143**
144** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
145** the International Astronomical Union nor the names of its
146** contributors may be used to endorse or promote products derived
147** from this software without specific prior written permission.
148**
149** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
150** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
151** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
152** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
153** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
154** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
155** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
156** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
157** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
158** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
159** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
160** POSSIBILITY OF SUCH DAMAGE.
161**
162*/
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