FACT++  1.0
pn00a.c
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1 #include "erfa.h"
2 
3 void eraPn00a(double date1, double date2,
4  double *dpsi, double *deps, double *epsa,
5  double rb[3][3], double rp[3][3], double rbp[3][3],
6  double rn[3][3], double rbpn[3][3])
7 /*
8 ** - - - - - - - - -
9 ** e r a P n 0 0 a
10 ** - - - - - - - - -
11 **
12 ** Precession-nutation, IAU 2000A model: a multi-purpose function,
13 ** supporting classical (equinox-based) use directly and CIO-based
14 ** use indirectly.
15 **
16 ** Given:
17 ** date1,date2 double TT as a 2-part Julian Date (Note 1)
18 **
19 ** Returned:
20 ** dpsi,deps double nutation (Note 2)
21 ** epsa double mean obliquity (Note 3)
22 ** rb double[3][3] frame bias matrix (Note 4)
23 ** rp double[3][3] precession matrix (Note 5)
24 ** rbp double[3][3] bias-precession matrix (Note 6)
25 ** rn double[3][3] nutation matrix (Note 7)
26 ** rbpn double[3][3] GCRS-to-true matrix (Notes 8,9)
27 **
28 ** Notes:
29 **
30 ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
31 ** convenient way between the two arguments. For example,
32 ** JD(TT)=2450123.7 could be expressed in any of these ways,
33 ** among others:
34 **
35 ** date1 date2
36 **
37 ** 2450123.7 0.0 (JD method)
38 ** 2451545.0 -1421.3 (J2000 method)
39 ** 2400000.5 50123.2 (MJD method)
40 ** 2450123.5 0.2 (date & time method)
41 **
42 ** The JD method is the most natural and convenient to use in
43 ** cases where the loss of several decimal digits of resolution
44 ** is acceptable. The J2000 method is best matched to the way
45 ** the argument is handled internally and will deliver the
46 ** optimum resolution. The MJD method and the date & time methods
47 ** are both good compromises between resolution and convenience.
48 **
49 ** 2) The nutation components (luni-solar + planetary, IAU 2000A) in
50 ** longitude and obliquity are in radians and with respect to the
51 ** equinox and ecliptic of date. Free core nutation is omitted;
52 ** for the utmost accuracy, use the eraPn00 function, where the
53 ** nutation components are caller-specified. For faster but
54 ** slightly less accurate results, use the eraPn00b function.
55 **
56 ** 3) The mean obliquity is consistent with the IAU 2000 precession.
57 **
58 ** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
59 ** equator and equinox by applying frame bias.
60 **
61 ** 5) The matrix rp transforms vectors from J2000.0 mean equator and
62 ** equinox to mean equator and equinox of date by applying
63 ** precession.
64 **
65 ** 6) The matrix rbp transforms vectors from GCRS to mean equator and
66 ** equinox of date by applying frame bias then precession. It is
67 ** the product rp x rb.
68 **
69 ** 7) The matrix rn transforms vectors from mean equator and equinox
70 ** of date to true equator and equinox of date by applying the
71 ** nutation (luni-solar + planetary).
72 **
73 ** 8) The matrix rbpn transforms vectors from GCRS to true equator and
74 ** equinox of date. It is the product rn x rbp, applying frame
75 ** bias, precession and nutation in that order.
76 **
77 ** 9) The X,Y,Z coordinates of the IAU 2000A Celestial Intermediate
78 ** Pole are elements (3,1-3) of the GCRS-to-true matrix,
79 ** i.e. rbpn[2][0-2].
80 **
81 ** 10) It is permissible to re-use the same array in the returned
82 ** arguments. The arrays are filled in the order given.
83 **
84 ** Called:
85 ** eraNut00a nutation, IAU 2000A
86 ** eraPn00 bias/precession/nutation results, IAU 2000
87 **
88 ** Reference:
89 **
90 ** Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
91 ** "Expressions for the Celestial Intermediate Pole and Celestial
92 ** Ephemeris Origin consistent with the IAU 2000A precession-
93 ** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
94 **
95 ** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
96 ** intermediate origin" (CIO) by IAU 2006 Resolution 2.
97 **
98 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
99 ** Derived, with permission, from the SOFA library. See notes at end of file.
100 */
101 {
102 /* Nutation. */
103  eraNut00a(date1, date2, dpsi, deps);
104 
105 /* Remaining results. */
106  eraPn00(date1, date2, *dpsi, *deps, epsa, rb, rp, rbp, rn, rbpn);
107 
108  return;
109 
110 }
111 /*----------------------------------------------------------------------
112 **
113 **
114 ** Copyright (C) 2013-2015, NumFOCUS Foundation.
115 ** All rights reserved.
116 **
117 ** This library is derived, with permission, from the International
118 ** Astronomical Union's "Standards of Fundamental Astronomy" library,
119 ** available from http://www.iausofa.org.
120 **
121 ** The ERFA version is intended to retain identical functionality to
122 ** the SOFA library, but made distinct through different function and
123 ** file names, as set out in the SOFA license conditions. The SOFA
124 ** original has a role as a reference standard for the IAU and IERS,
125 ** and consequently redistribution is permitted only in its unaltered
126 ** state. The ERFA version is not subject to this restriction and
127 ** therefore can be included in distributions which do not support the
128 ** concept of "read only" software.
129 **
130 ** Although the intent is to replicate the SOFA API (other than
131 ** replacement of prefix names) and results (with the exception of
132 ** bugs; any that are discovered will be fixed), SOFA is not
133 ** responsible for any errors found in this version of the library.
134 **
135 ** If you wish to acknowledge the SOFA heritage, please acknowledge
136 ** that you are using a library derived from SOFA, rather than SOFA
137 ** itself.
138 **
139 **
140 ** TERMS AND CONDITIONS
141 **
142 ** Redistribution and use in source and binary forms, with or without
143 ** modification, are permitted provided that the following conditions
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145 **
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148 **
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153 **
154 ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
155 ** the International Astronomical Union nor the names of its
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160 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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eraPn00a
void eraPn00a(double date1, double date2, double *dpsi, double *deps, double *epsa, double rb[3][3], double rp[3][3], double rbp[3][3], double rn[3][3], double rbpn[3][3])
Definition: pn00a.c:3
eraNut00a
void eraNut00a(double date1, double date2, double *dpsi, double *deps)
Definition: nut00a.c:3
eraPn00
void eraPn00(double date1, double date2, double dpsi, double deps, double *epsa, double rb[3][3], double rp[3][3], double rbp[3][3], double rn[3][3], double rbpn[3][3])
Definition: pn00.c:3