File Coverage

erfasrc/src/lteceq.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 eraLteceq(double epj, double dl, double db, double dr, double dd)
4		/*
5		** - - - - - - - - - -
6		** e r a L t e c e q
7		** - - - - - - - - - -
8		**
9		** Transformation from ecliptic coordinates (mean equinox and ecliptic
10		** of date) to ICRS RA,Dec, using a long-term precession model.
11		**
12		** Given:
13		** epj double Julian epoch (TT)
14		** dl,db double ecliptic longitude and latitude (radians)
15		**
16		** Returned:
17		** dr,dd double ICRS right ascension and declination (radians)
18		**
19		** 1) No assumptions are made about whether the coordinates represent
20		** starlight and embody astrometric effects such as parallax or
21		** aberration.
22		**
23		** 2) The transformation is approximately that from ecliptic longitude
24		** and latitude (mean equinox and ecliptic of date) to mean J2000.0
25		** right ascension and declination, with only frame bias (always
26		** less than 25 mas) to disturb this classical picture.
27		**
28		** 3) The Vondrak et al. (2011, 2012) 400 millennia precession model
29		** agrees with the IAU 2006 precession at J2000.0 and stays within
30		** 100 microarcseconds during the 20th and 21st centuries. It is
31		** accurate to a few arcseconds throughout the historical period,
32		** worsening to a few tenths of a degree at the end of the
33		** +/- 200,000 year time span.
34		**
35		** Called:
36		** eraS2c spherical coordinates to unit vector
37		** eraLtecm J2000.0 to ecliptic rotation matrix, long term
38		** eraTrxp product of transpose of r-matrix and p-vector
39		** eraC2s unit vector to spherical coordinates
40		** eraAnp normalize angle into range 0 to 2pi
41		** eraAnpm normalize angle into range +/- pi
42		**
43		** References:
44		**
45		** Vondrak, J., Capitaine, N. and Wallace, P., 2011, New precession
46		** expressions, valid for long time intervals, Astron.Astrophys. 534,
47		** A22
48		**
49		** Vondrak, J., Capitaine, N. and Wallace, P., 2012, New precession
50		** expressions, valid for long time intervals (Corrigendum),
51		** Astron.Astrophys. 541, C1
52		**
53		** Copyright (C) 2013-2020, NumFOCUS Foundation.
54		** Derived, with permission, from the SOFA library. See notes at end of file.
55		*/
56		{
57		double rm[3][3], v1[3], v2[3], a, b;
58
59
60		/* Spherical to Cartesian. */
61	0	eraS2c(dl, db, v1);
62
63		/* Rotation matrix, ICRS equatorial to ecliptic. */
64	0	eraLtecm(epj, rm);
65
66		/* The transformation from ecliptic to ICRS. */
67	0	eraTrxp(rm, v1, v2);
68
69		/* Cartesian to spherical. */
70	0	eraC2s(v2, &a, &b);
71
72		/* Express in conventional ranges. */
73	0	*dr = eraAnp(a);
74	0	*dd = eraAnpm(b);
75
76	0	}
77		/*----------------------------------------------------------------------
78		**
79		**
80		** Copyright (C) 2013-2020, NumFOCUS Foundation.
81		** All rights reserved.
82		**
83		** This library is derived, with permission, from the International
84		** Astronomical Union's "Standards of Fundamental Astronomy" library,
85		** available from http://www.iausofa.org.
86		**
87		** The ERFA version is intended to retain identical functionality to
88		** the SOFA library, but made distinct through different function and
89		** file names, as set out in the SOFA license conditions. The SOFA
90		** original has a role as a reference standard for the IAU and IERS,
91		** and consequently redistribution is permitted only in its unaltered
92		** state. The ERFA version is not subject to this restriction and
93		** therefore can be included in distributions which do not support the
94		** concept of "read only" software.
95		**
96		** Although the intent is to replicate the SOFA API (other than
97		** replacement of prefix names) and results (with the exception of
98		** bugs; any that are discovered will be fixed), SOFA is not
99		** responsible for any errors found in this version of the library.
100		**
101		** If you wish to acknowledge the SOFA heritage, please acknowledge
102		** that you are using a library derived from SOFA, rather than SOFA
103		** itself.
104		**
105		**
106		** TERMS AND CONDITIONS
107		**
108		** Redistribution and use in source and binary forms, with or without
109		** modification, are permitted provided that the following conditions
110		** are met:
111		**
112		** 1 Redistributions of source code must retain the above copyright
113		** notice, this list of conditions and the following disclaimer.
114		**
115		** 2 Redistributions in binary form must reproduce the above copyright
116		** notice, this list of conditions and the following disclaimer in
117		** the documentation and/or other materials provided with the
118		** distribution.
119		**
120		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
121		** the International Astronomical Union nor the names of its
122		** contributors may be used to endorse or promote products derived
123		** from this software without specific prior written permission.
124		**
125		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
126		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
127		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
128		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
129		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
130		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
131		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
132		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
133		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
134		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
135		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
136		** POSSIBILITY OF SUCH DAMAGE.
137		**
138		*/