| 1 | #include "erfa.h" | 
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| 2 |  | 
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| 3 | void eraPn00(double date1, double date2, double dpsi, double deps, | 
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| 4 | 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 | **   e r a P n 0 0 | 
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| 10 | **  - - - - - - - - | 
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| 11 | ** | 
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| 12 | **  Precession-nutation, IAU 2000 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 | **  Given: | 
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| 17 | **     date1,date2  double          TT as a 2-part Julian Date (Note 1) | 
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| 18 | **     dpsi,deps    double          nutation (Note 2) | 
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| 19 | ** | 
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| 20 | **  Returned: | 
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| 21 | **     epsa         double          mean obliquity (Note 3) | 
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| 22 | **     rb           double[3][3]    frame bias matrix (Note 4) | 
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| 23 | **     rp           double[3][3]    precession matrix (Note 5) | 
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| 24 | **     rbp          double[3][3]    bias-precession matrix (Note 6) | 
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| 25 | **     rn           double[3][3]    nutation matrix (Note 7) | 
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| 26 | **     rbpn         double[3][3]    GCRS-to-true matrix (Note 8) | 
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| 27 | ** | 
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| 28 | **  Notes: | 
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| 29 | ** | 
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| 30 | **  1) The TT date date1+date2 is a Julian Date, apportioned in any | 
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| 31 | **     convenient way between the two arguments.  For example, | 
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| 32 | **     JD(TT)=2450123.7 could be expressed in any of these ways, | 
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| 33 | **     among others: | 
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| 34 | ** | 
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| 35 | **            date1          date2 | 
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| 36 | ** | 
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| 37 | **         2450123.7           0.0       (JD method) | 
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| 38 | **         2451545.0       -1421.3       (J2000 method) | 
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| 39 | **         2400000.5       50123.2       (MJD method) | 
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| 40 | **         2450123.5           0.2       (date & time method) | 
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| 41 | ** | 
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| 42 | **     The JD method is the most natural and convenient to use in | 
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| 43 | **     cases where the loss of several decimal digits of resolution | 
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| 44 | **     is acceptable.  The J2000 method is best matched to the way | 
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| 45 | **     the argument is handled internally and will deliver the | 
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| 46 | **     optimum resolution.  The MJD method and the date & time methods | 
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| 47 | **     are both good compromises between resolution and convenience. | 
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| 48 | ** | 
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| 49 | **  2) The caller is responsible for providing the nutation components; | 
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| 50 | **     they are in longitude and obliquity, in radians and are with | 
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| 51 | **     respect to the equinox and ecliptic of date.  For high-accuracy | 
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| 52 | **     applications, free core nutation should be included as well as | 
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| 53 | **     any other relevant corrections to the position of the CIP. | 
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| 54 | ** | 
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| 55 | **  3) The returned mean obliquity is consistent with the IAU 2000 | 
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| 56 | **     precession-nutation models. | 
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| 57 | ** | 
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| 58 | **  4) The matrix rb transforms vectors from GCRS to J2000.0 mean | 
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| 59 | **     equator and equinox by applying frame bias. | 
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| 60 | ** | 
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| 61 | **  5) The matrix rp transforms vectors from J2000.0 mean equator and | 
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| 62 | **     equinox to mean equator and equinox of date by applying | 
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| 63 | **     precession. | 
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| 64 | ** | 
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| 65 | **  6) The matrix rbp transforms vectors from GCRS to mean equator and | 
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| 66 | **     equinox of date by applying frame bias then precession.  It is | 
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| 67 | **     the product rp x rb. | 
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| 68 | ** | 
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| 69 | **  7) The matrix rn transforms vectors from mean equator and equinox of | 
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| 70 | **     date to true equator and equinox of date by applying the nutation | 
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| 71 | **     (luni-solar + planetary). | 
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| 72 | ** | 
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| 73 | **  8) The matrix rbpn transforms vectors from GCRS to true equator and | 
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| 74 | **     equinox of date.  It is the product rn x rbp, applying frame | 
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| 75 | **     bias, precession and nutation in that order. | 
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| 76 | ** | 
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| 77 | **  9) It is permissible to re-use the same array in the returned | 
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| 78 | **     arguments.  The arrays are filled in the order given. | 
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| 79 | ** | 
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| 80 | **  Called: | 
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| 81 | **     eraPr00      IAU 2000 precession adjustments | 
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| 82 | **     eraObl80     mean obliquity, IAU 1980 | 
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| 83 | **     eraBp00      frame bias and precession matrices, IAU 2000 | 
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| 84 | **     eraCr        copy r-matrix | 
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| 85 | **     eraNumat     form nutation matrix | 
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| 86 | **     eraRxr       product of two r-matrices | 
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| 87 | ** | 
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| 88 | **  Reference: | 
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| 89 | ** | 
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| 90 | **     Capitaine, N., Chapront, J., Lambert, S. and Wallace, P., | 
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| 91 | **     "Expressions for the Celestial Intermediate Pole and Celestial | 
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| 92 | **     Ephemeris Origin consistent with the IAU 2000A precession- | 
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| 93 | **     nutation model", Astron.Astrophys. 400, 1145-1154 (2003) | 
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| 94 | ** | 
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| 95 | **     n.b. The celestial ephemeris origin (CEO) was renamed "celestial | 
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| 96 | **          intermediate origin" (CIO) by IAU 2006 Resolution 2. | 
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| 97 | ** | 
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| 98 | **  Copyright (C) 2013-2017, NumFOCUS Foundation. | 
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| 99 | **  Derived, with permission, from the SOFA library.  See notes at end of file. | 
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| 100 | */ | 
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| 101 | { | 
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| 102 | double dpsipr, depspr, rbpw[3][3], rnw[3][3]; | 
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| 103 |  | 
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| 104 |  | 
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| 105 | /* IAU 2000 precession-rate adjustments. */ | 
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| 106 | eraPr00(date1, date2, &dpsipr, &depspr); | 
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| 107 |  | 
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| 108 | /* Mean obliquity, consistent with IAU 2000 precession-nutation. */ | 
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| 109 | *epsa = eraObl80(date1, date2) + depspr; | 
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| 110 |  | 
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| 111 | /* Frame bias and precession matrices and their product. */ | 
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| 112 | eraBp00(date1, date2, rb, rp, rbpw); | 
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| 113 | eraCr(rbpw, rbp); | 
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| 114 |  | 
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| 115 | /* Nutation matrix. */ | 
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| 116 | eraNumat(*epsa, dpsi, deps, rnw); | 
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| 117 | eraCr(rnw, rn); | 
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| 118 |  | 
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| 119 | /* Bias-precession-nutation matrix (classical). */ | 
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| 120 | eraRxr(rnw, rbpw, rbpn); | 
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| 121 |  | 
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| 122 | return; | 
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| 123 |  | 
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| 124 | } | 
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| 125 | /*---------------------------------------------------------------------- | 
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| 126 | ** | 
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| 127 | ** | 
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| 128 | **  Copyright (C) 2013-2017, NumFOCUS Foundation. | 
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| 129 | **  All rights reserved. | 
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| 130 | ** | 
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| 131 | **  This library is derived, with permission, from the International | 
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| 132 | **  Astronomical Union's "Standards of Fundamental Astronomy" library, | 
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| 133 | **  available from http://www.iausofa.org. | 
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| 134 | ** | 
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| 135 | **  The ERFA version is intended to retain identical functionality to | 
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| 136 | **  the SOFA library, but made distinct through different function and | 
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| 137 | **  file names, as set out in the SOFA license conditions.  The SOFA | 
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| 138 | **  original has a role as a reference standard for the IAU and IERS, | 
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| 139 | **  and consequently redistribution is permitted only in its unaltered | 
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| 140 | **  state.  The ERFA version is not subject to this restriction and | 
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| 141 | **  therefore can be included in distributions which do not support the | 
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| 142 | **  concept of "read only" software. | 
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| 143 | ** | 
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| 144 | **  Although the intent is to replicate the SOFA API (other than | 
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| 145 | **  replacement of prefix names) and results (with the exception of | 
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| 146 | **  bugs;  any that are discovered will be fixed), SOFA is not | 
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| 147 | **  responsible for any errors found in this version of the library. | 
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| 148 | ** | 
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| 149 | **  If you wish to acknowledge the SOFA heritage, please acknowledge | 
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| 150 | **  that you are using a library derived from SOFA, rather than SOFA | 
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| 151 | **  itself. | 
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| 152 | ** | 
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| 153 | ** | 
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| 154 | **  TERMS AND CONDITIONS | 
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| 155 | ** | 
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| 156 | **  Redistribution and use in source and binary forms, with or without | 
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| 157 | **  modification, are permitted provided that the following conditions | 
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| 158 | **  are met: | 
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| 159 | ** | 
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| 160 | **  1 Redistributions of source code must retain the above copyright | 
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| 161 | **    notice, this list of conditions and the following disclaimer. | 
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| 162 | ** | 
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| 163 | **  2 Redistributions in binary form must reproduce the above copyright | 
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| 164 | **    notice, this list of conditions and the following disclaimer in | 
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| 165 | **    the documentation and/or other materials provided with the | 
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| 166 | **    distribution. | 
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| 167 | ** | 
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| 168 | **  3 Neither the name of the Standards Of Fundamental Astronomy Board, | 
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| 169 | **    the International Astronomical Union nor the names of its | 
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| 170 | **    contributors may be used to endorse or promote products derived | 
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| 171 | **    from this software without specific prior written permission. | 
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| 172 | ** | 
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| 173 | **  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | 
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| 174 | **  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | 
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| 175 | **  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | 
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| 176 | **  FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE | 
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| 177 | **  COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | 
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| 178 | **  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | 
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| 179 | **  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | 
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| 180 | **  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | 
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| 181 | **  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | 
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| 182 | **  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | 
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| 183 | **  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | 
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| 184 | **  POSSIBILITY OF SUCH DAMAGE. | 
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| 185 | ** | 
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| 186 | */ | 
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