File Coverage

erfasrc/src/lteqec.c

Criterion	Covered	Total	%
statement	0	8	0.0
branch			n/a
condition			n/a
subroutine			n/a
pod			n/a
total	0	8	0.0

line	stmt	code
1		#include "erfa.h"
2
3	0	void eraLteqec(double epj, double dr, double dd, double dl, double db)
4		/*
5		** - - - - - - - - - -
6		** e r a L t e q e c
7		** - - - - - - - - - -
8		**
9		** Transformation from ICRS equatorial coordinates to ecliptic
10		** coordinates (mean equinox and ecliptic of date) using a long-term
11		** precession model.
12		**
13		** Given:
14		** epj double Julian epoch (TT)
15		** dr,dd double ICRS right ascension and declination (radians)
16		**
17		** Returned:
18		** dl,db double ecliptic longitude and latitude (radians)
19		**
20		** 1) No assumptions are made about whether the coordinates represent
21		** starlight and embody astrometric effects such as parallax or
22		** aberration.
23		**
24		** 2) The transformation is approximately that from mean J2000.0 right
25		** ascension and declination to ecliptic longitude and latitude
26		** (mean equinox and ecliptic of date), with only frame bias (always
27		** less than 25 mas) to disturb this classical picture.
28		**
29		** 3) The Vondrak et al. (2011, 2012) 400 millennia precession model
30		** agrees with the IAU 2006 precession at J2000.0 and stays within
31		** 100 microarcseconds during the 20th and 21st centuries. It is
32		** accurate to a few arcseconds throughout the historical period,
33		** worsening to a few tenths of a degree at the end of the
34		** +/- 200,000 year time span.
35		**
36		** Called:
37		** eraS2c spherical coordinates to unit vector
38		** eraLtecm J2000.0 to ecliptic rotation matrix, long term
39		** eraRxp product of r-matrix and p-vector
40		** eraC2s unit vector to spherical coordinates
41		** eraAnp normalize angle into range 0 to 2pi
42		** eraAnpm normalize angle into range +/- pi
43		**
44		** References:
45		**
46		** Vondrak, J., Capitaine, N. and Wallace, P., 2011, New precession
47		** expressions, valid for long time intervals, Astron.Astrophys. 534,
48		** A22
49		**
50		** Vondrak, J., Capitaine, N. and Wallace, P., 2012, New precession
51		** expressions, valid for long time intervals (Corrigendum),
52		** Astron.Astrophys. 541, C1
53		**
54		** Copyright (C) 2013-2019, NumFOCUS Foundation.
55		** Derived, with permission, from the SOFA library. See notes at end of file.
56		*/
57		{
58		double rm[3][3], v1[3], v2[3], a, b;
59
60
61		/* Spherical to Cartesian. */
62	0	eraS2c(dr, dd, v1);
63
64		/* Rotation matrix, ICRS equatorial to ecliptic. */
65	0	eraLtecm(epj, rm);
66
67		/* The transformation from ICRS to ecliptic. */
68	0	eraRxp(rm, v1, v2);
69
70		/* Cartesian to spherical. */
71	0	eraC2s(v2, &a, &b);
72
73		/* Express in conventional ranges. */
74	0	*dl = eraAnp(a);
75	0	*db = eraAnpm(b);
76
77	0	}
78		/*----------------------------------------------------------------------
79		**
80		**
81		** Copyright (C) 2013-2019, NumFOCUS Foundation.
82		** All rights reserved.
83		**
84		** This library is derived, with permission, from the International
85		** Astronomical Union's "Standards of Fundamental Astronomy" library,
86		** available from http://www.iausofa.org.
87		**
88		** The ERFA version is intended to retain identical functionality to
89		** the SOFA library, but made distinct through different function and
90		** file names, as set out in the SOFA license conditions. The SOFA
91		** original has a role as a reference standard for the IAU and IERS,
92		** and consequently redistribution is permitted only in its unaltered
93		** state. The ERFA version is not subject to this restriction and
94		** therefore can be included in distributions which do not support the
95		** concept of "read only" software.
96		**
97		** Although the intent is to replicate the SOFA API (other than
98		** replacement of prefix names) and results (with the exception of
99		** bugs; any that are discovered will be fixed), SOFA is not
100		** responsible for any errors found in this version of the library.
101		**
102		** If you wish to acknowledge the SOFA heritage, please acknowledge
103		** that you are using a library derived from SOFA, rather than SOFA
104		** itself.
105		**
106		**
107		** TERMS AND CONDITIONS
108		**
109		** Redistribution and use in source and binary forms, with or without
110		** modification, are permitted provided that the following conditions
111		** are met:
112		**
113		** 1 Redistributions of source code must retain the above copyright
114		** notice, this list of conditions and the following disclaimer.
115		**
116		** 2 Redistributions in binary form must reproduce the above copyright
117		** notice, this list of conditions and the following disclaimer in
118		** the documentation and/or other materials provided with the
119		** distribution.
120		**
121		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
122		** the International Astronomical Union nor the names of its
123		** contributors may be used to endorse or promote products derived
124		** from this software without specific prior written permission.
125		**
126		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
127		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
128		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
129		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
130		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
131		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
132		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
133		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
134		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
135		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
136		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
137		** POSSIBILITY OF SUCH DAMAGE.
138		**
139		*/