| 1 | #include "sofa.h"
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| 2 |
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| 3 | void iauPn00a(double date1, double date2,
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| 4 | double *dpsi, double *deps, double *epsa,
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| 5 | double rb[3][3], double rp[3][3], double rbp[3][3],
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| 6 | double rn[3][3], double rbpn[3][3])
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| 7 | /*
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| 8 | ** - - - - - - - - -
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| 9 | ** i a u P n 0 0 a
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| 10 | ** - - - - - - - - -
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| 11 | **
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| 12 | ** Precession-nutation, IAU 2000A model: a multi-purpose function,
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| 13 | ** supporting classical (equinox-based) use directly and CIO-based
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| 14 | ** use indirectly.
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| 15 | **
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| 16 | ** This function is part of the International Astronomical Union's
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| 17 | ** SOFA (Standards Of Fundamental Astronomy) software collection.
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| 18 | **
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| 19 | ** Status: support function.
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| 20 | **
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| 21 | ** Given:
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| 22 | ** date1,date2 double TT as a 2-part Julian Date (Note 1)
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| 23 | **
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| 24 | ** Returned:
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| 25 | ** dpsi,deps double nutation (Note 2)
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| 26 | ** epsa double mean obliquity (Note 3)
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| 27 | ** rb double[3][3] frame bias matrix (Note 4)
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| 28 | ** rp double[3][3] precession matrix (Note 5)
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| 29 | ** rbp double[3][3] bias-precession matrix (Note 6)
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| 30 | ** rn double[3][3] nutation matrix (Note 7)
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| 31 | ** rbpn double[3][3] GCRS-to-true matrix (Notes 8,9)
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| 32 | **
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| 33 | ** Notes:
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| 34 | **
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| 35 | ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
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| 36 | ** convenient way between the two arguments. For example,
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| 37 | ** JD(TT)=2450123.7 could be expressed in any of these ways,
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| 38 | ** among others:
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| 39 | **
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| 40 | ** date1 date2
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| 41 | **
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| 42 | ** 2450123.7 0.0 (JD method)
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| 43 | ** 2451545.0 -1421.3 (J2000 method)
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| 44 | ** 2400000.5 50123.2 (MJD method)
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| 45 | ** 2450123.5 0.2 (date & time method)
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| 46 | **
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| 47 | ** The JD method is the most natural and convenient to use in
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| 48 | ** cases where the loss of several decimal digits of resolution
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| 49 | ** is acceptable. The J2000 method is best matched to the way
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| 50 | ** the argument is handled internally and will deliver the
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| 51 | ** optimum resolution. The MJD method and the date & time methods
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| 52 | ** are both good compromises between resolution and convenience.
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| 53 | **
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| 54 | ** 2) The nutation components (luni-solar + planetary, IAU 2000A) in
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| 55 | ** longitude and obliquity are in radians and with respect to the
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| 56 | ** equinox and ecliptic of date. Free core nutation is omitted;
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| 57 | ** for the utmost accuracy, use the iauPn00 function, where the
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| 58 | ** nutation components are caller-specified. For faster but
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| 59 | ** slightly less accurate results, use the iauPn00b function.
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| 60 | **
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| 61 | ** 3) The mean obliquity is consistent with the IAU 2000 precession.
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| 62 | **
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| 63 | ** 4) The matrix rb transforms vectors from GCRS to J2000.0 mean
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| 64 | ** equator and equinox by applying frame bias.
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| 65 | **
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| 66 | ** 5) The matrix rp transforms vectors from J2000.0 mean equator and
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| 67 | ** equinox to mean equator and equinox of date by applying
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| 68 | ** precession.
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| 69 | **
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| 70 | ** 6) The matrix rbp transforms vectors from GCRS to mean equator and
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| 71 | ** equinox of date by applying frame bias then precession. It is
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| 72 | ** the product rp x rb.
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| 73 | **
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| 74 | ** 7) The matrix rn transforms vectors from mean equator and equinox
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| 75 | ** of date to true equator and equinox of date by applying the
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| 76 | ** nutation (luni-solar + planetary).
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| 77 | **
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| 78 | ** 8) The matrix rbpn transforms vectors from GCRS to true equator and
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| 79 | ** equinox of date. It is the product rn x rbp, applying frame
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| 80 | ** bias, precession and nutation in that order.
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| 81 | **
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| 82 | ** 9) The X,Y,Z coordinates of the IAU 2000A Celestial Intermediate
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| 83 | ** Pole are elements (3,1-3) of the GCRS-to-true matrix,
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| 84 | ** i.e. rbpn[2][0-2].
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| 85 | **
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| 86 | ** 10) It is permissible to re-use the same array in the returned
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| 87 | ** arguments. The arrays are filled in the order given.
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| 88 | **
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| 89 | ** Called:
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| 90 | ** iauNut00a nutation, IAU 2000A
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| 91 | ** iauPn00 bias/precession/nutation results, IAU 2000
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| 92 | **
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| 93 | ** Reference:
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| 94 | **
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| 95 | ** Capitaine, N., Chapront, J., Lambert, S. and Wallace, P.,
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| 96 | ** "Expressions for the Celestial Intermediate Pole and Celestial
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| 97 | ** Ephemeris Origin consistent with the IAU 2000A precession-
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| 98 | ** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
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| 99 | **
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| 100 | ** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
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| 101 | ** intermediate origin" (CIO) by IAU 2006 Resolution 2.
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| 102 | **
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| 103 | ** This revision: 2013 November 14
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| 104 | **
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| 105 | ** SOFA release 2015-02-09
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| 106 | **
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| 107 | ** Copyright (C) 2015 IAU SOFA Board. See notes at end.
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| 108 | */
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| 109 | {
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| 110 | /* Nutation. */
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| 111 | iauNut00a(date1, date2, dpsi, deps);
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| 112 |
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| 113 | /* Remaining results. */
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| 114 | iauPn00(date1, date2, *dpsi, *deps, epsa, rb, rp, rbp, rn, rbpn);
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| 115 |
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| 116 | return;
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| 117 |
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| 118 | /*----------------------------------------------------------------------
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| 119 | **
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| 120 | ** Copyright (C) 2015
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| 121 | ** Standards Of Fundamental Astronomy Board
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| 122 | ** of the International Astronomical Union.
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| 123 | **
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| 124 | ** =====================
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| 125 | ** SOFA Software License
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| 126 | ** =====================
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| 127 | **
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| 128 | ** NOTICE TO USER:
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| 129 | **
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| 130 | ** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
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| 131 | ** CONDITIONS WHICH APPLY TO ITS USE.
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| 132 | **
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| 133 | ** 1. The Software is owned by the IAU SOFA Board ("SOFA").
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| 134 | **
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| 135 | ** 2. Permission is granted to anyone to use the SOFA software for any
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| 136 | ** purpose, including commercial applications, free of charge and
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| 137 | ** without payment of royalties, subject to the conditions and
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| 138 | ** restrictions listed below.
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| 139 | **
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| 140 | ** 3. You (the user) may copy and distribute SOFA source code to others,
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| 141 | ** and use and adapt its code and algorithms in your own software,
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| 142 | ** on a world-wide, royalty-free basis. That portion of your
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| 143 | ** distribution that does not consist of intact and unchanged copies
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| 144 | ** of SOFA source code files is a "derived work" that must comply
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| 145 | ** with the following requirements:
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| 146 | **
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| 147 | ** a) Your work shall be marked or carry a statement that it
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| 148 | ** (i) uses routines and computations derived by you from
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| 149 | ** software provided by SOFA under license to you; and
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| 150 | ** (ii) does not itself constitute software provided by and/or
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| 151 | ** endorsed by SOFA.
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| 152 | **
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| 153 | ** b) The source code of your derived work must contain descriptions
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| 154 | ** of how the derived work is based upon, contains and/or differs
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| 155 | ** from the original SOFA software.
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| 156 | **
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| 157 | ** c) The names of all routines in your derived work shall not
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| 158 | ** include the prefix "iau" or "sofa" or trivial modifications
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| 159 | ** thereof such as changes of case.
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| 160 | **
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| 161 | ** d) The origin of the SOFA components of your derived work must
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| 162 | ** not be misrepresented; you must not claim that you wrote the
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| 163 | ** original software, nor file a patent application for SOFA
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| 164 | ** software or algorithms embedded in the SOFA software.
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| 165 | **
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| 166 | ** e) These requirements must be reproduced intact in any source
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| 167 | ** distribution and shall apply to anyone to whom you have
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| 168 | ** granted a further right to modify the source code of your
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| 169 | ** derived work.
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| 170 | **
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| 171 | ** Note that, as originally distributed, the SOFA software is
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| 172 | ** intended to be a definitive implementation of the IAU standards,
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| 173 | ** and consequently third-party modifications are discouraged. All
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| 174 | ** variations, no matter how minor, must be explicitly marked as
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| 175 | ** such, as explained above.
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| 176 | **
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| 177 | ** 4. You shall not cause the SOFA software to be brought into
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| 178 | ** disrepute, either by misuse, or use for inappropriate tasks, or
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| 179 | ** by inappropriate modification.
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| 180 | **
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| 181 | ** 5. The SOFA software is provided "as is" and SOFA makes no warranty
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| 182 | ** as to its use or performance. SOFA does not and cannot warrant
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| 183 | ** the performance or results which the user may obtain by using the
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| 184 | ** SOFA software. SOFA makes no warranties, express or implied, as
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| 185 | ** to non-infringement of third party rights, merchantability, or
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| 186 | ** fitness for any particular purpose. In no event will SOFA be
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| 187 | ** liable to the user for any consequential, incidental, or special
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| 188 | ** damages, including any lost profits or lost savings, even if a
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| 189 | ** SOFA representative has been advised of such damages, or for any
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| 190 | ** claim by any third party.
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| 191 | **
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| 192 | ** 6. The provision of any version of the SOFA software under the terms
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| 193 | ** and conditions specified herein does not imply that future
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| 194 | ** versions will also be made available under the same terms and
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| 195 | ** conditions.
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| 196 | *
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| 197 | ** In any published work or commercial product which uses the SOFA
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| 198 | ** software directly, acknowledgement (see www.iausofa.org) is
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| 199 | ** appreciated.
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| 200 | **
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| 201 | ** Correspondence concerning SOFA software should be addressed as
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| 202 | ** follows:
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| 203 | **
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| 204 | ** By email: sofa@ukho.gov.uk
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| 205 | ** By post: IAU SOFA Center
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| 206 | ** HM Nautical Almanac Office
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| 207 | ** UK Hydrographic Office
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| 208 | ** Admiralty Way, Taunton
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| 209 | ** Somerset, TA1 2DN
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| 210 | ** United Kingdom
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| 211 | **
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| 212 | **--------------------------------------------------------------------*/
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| 213 | }
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