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author | William Joye <wjoye@cfa.harvard.edu> | 2017-12-08 18:59:21 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2017-12-08 18:59:21 (GMT) |
commit | 4432c8d7e1ccb371db03e13cdb5378fceaa5ad04 (patch) | |
tree | 52449d211eba99b24d2e4f6e66193f9511c60b59 /ast/erfa/ldsun.c | |
parent | d8a2dbd825159e4a57ec0c6f4465f62be9e05111 (diff) | |
download | blt-4432c8d7e1ccb371db03e13cdb5378fceaa5ad04.zip blt-4432c8d7e1ccb371db03e13cdb5378fceaa5ad04.tar.gz blt-4432c8d7e1ccb371db03e13cdb5378fceaa5ad04.tar.bz2 |
upgrade AST
Diffstat (limited to 'ast/erfa/ldsun.c')
-rw-r--r-- | ast/erfa/ldsun.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/ast/erfa/ldsun.c b/ast/erfa/ldsun.c new file mode 100644 index 0000000..62ed117 --- /dev/null +++ b/ast/erfa/ldsun.c @@ -0,0 +1,115 @@ +#include "erfa.h" + +void eraLdsun(double p[3], double e[3], double em, double p1[3]) +/* +** - - - - - - - - - +** e r a L d s u n +** - - - - - - - - - +** +** Deflection of starlight by the Sun. +** +** Given: +** p double[3] direction from observer to star (unit vector) +** e double[3] direction from Sun to observer (unit vector) +** em double distance from Sun to observer (au) +** +** Returned: +** p1 double[3] observer to deflected star (unit vector) +** +** Notes: +** +** 1) The source is presumed to be sufficiently distant that its +** directions seen from the Sun and the observer are essentially +** the same. +** +** 2) The deflection is restrained when the angle between the star and +** the center of the Sun is less than a threshold value, falling to +** zero deflection for zero separation. The chosen threshold value +** is within the solar limb for all solar-system applications, and +** is about 5 arcminutes for the case of a terrestrial observer. +** +** 3) The arguments p and p1 can be the same array. +** +** Called: +** eraLd light deflection by a solar-system body +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** Derived, with permission, from the SOFA library. See notes at end of file. +*/ +{ + double em2, dlim; + + +/* Deflection limiter (smaller for distant observers). */ + em2 = em*em; + if ( em2 < 1.0 ) em2 = 1.0; + dlim = 1e-6 / (em2 > 1.0 ? em2 : 1.0); + +/* Apply the deflection. */ + eraLd(1.0, p, p, e, em, dlim, p1); + +/* Finished. */ + +} +/*---------------------------------------------------------------------- +** +** +** Copyright (C) 2013-2016, NumFOCUS Foundation. +** All rights reserved. +** +** This library is derived, with permission, from the International +** Astronomical Union's "Standards of Fundamental Astronomy" library, +** available from http://www.iausofa.org. +** +** The ERFA version is intended to retain identical functionality to +** the SOFA library, but made distinct through different function and +** file names, as set out in the SOFA license conditions. The SOFA +** original has a role as a reference standard for the IAU and IERS, +** and consequently redistribution is permitted only in its unaltered +** state. The ERFA version is not subject to this restriction and +** therefore can be included in distributions which do not support the +** concept of "read only" software. +** +** Although the intent is to replicate the SOFA API (other than +** replacement of prefix names) and results (with the exception of +** bugs; any that are discovered will be fixed), SOFA is not +** responsible for any errors found in this version of the library. +** +** If you wish to acknowledge the SOFA heritage, please acknowledge +** that you are using a library derived from SOFA, rather than SOFA +** itself. +** +** +** TERMS AND CONDITIONS +** +** Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions +** are met: +** +** 1 Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** +** 2 Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** +** 3 Neither the name of the Standards Of Fundamental Astronomy Board, +** the International Astronomical Union nor the names of its +** contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +** POSSIBILITY OF SUCH DAMAGE. +** +*/ |