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Diffstat (limited to 'ast/erfa/icrs2g.c')
| -rw-r--r-- | ast/erfa/icrs2g.c | 170 |
1 files changed, 0 insertions, 170 deletions
diff --git a/ast/erfa/icrs2g.c b/ast/erfa/icrs2g.c deleted file mode 100644 index cf59118..0000000 --- a/ast/erfa/icrs2g.c +++ /dev/null @@ -1,170 +0,0 @@ -#include "erfa.h" - -void eraIcrs2g ( double dr, double dd, double *dl, double *db ) -/* -** - - - - - - - - - - -** e r a I c r s 2 g -** - - - - - - - - - - -** -** Transformation from ICRS to Galactic Coordinates. -** -** Given: -** dr double ICRS right ascension (radians) -** dd double ICRS declination (radians) -** -** Returned: -** dl double galactic longitude (radians) -** db double galactic latitude (radians) -** -** Notes: -** -** 1) The IAU 1958 system of Galactic coordinates was defined with -** respect to the now obsolete reference system FK4 B1950.0. When -** interpreting the system in a modern context, several factors have -** to be taken into account: -** -** . The inclusion in FK4 positions of the E-terms of aberration. -** -** . The distortion of the FK4 proper motion system by differential -** Galactic rotation. -** -** . The use of the B1950.0 equinox rather than the now-standard -** J2000.0. -** -** . The frame bias between ICRS and the J2000.0 mean place system. -** -** The Hipparcos Catalogue (Perryman & ESA 1997) provides a rotation -** matrix that transforms directly between ICRS and Galactic -** coordinates with the above factors taken into account. The -** matrix is derived from three angles, namely the ICRS coordinates -** of the Galactic pole and the longitude of the ascending node of -** the galactic equator on the ICRS equator. They are given in -** degrees to five decimal places and for canonical purposes are -** regarded as exact. In the Hipparcos Catalogue the matrix -** elements are given to 10 decimal places (about 20 microarcsec). -** In the present ERFA function the matrix elements have been -** recomputed from the canonical three angles and are given to 30 -** decimal places. -** -** 2) The inverse transformation is performed by the function eraG2icrs. -** -** Called: -** eraAnp normalize angle into range 0 to 2pi -** eraAnpm normalize angle into range +/- pi -** eraS2c spherical coordinates to unit vector -** eraRxp product of r-matrix and p-vector -** eraC2s p-vector to spherical -** -** Reference: -** Perryman M.A.C. & ESA, 1997, ESA SP-1200, The Hipparcos and Tycho -** catalogues. Astrometric and photometric star catalogues -** derived from the ESA Hipparcos Space Astrometry Mission. ESA -** Publications Division, Noordwijk, Netherlands. -** -** Copyright (C) 2013-2016, NumFOCUS Foundation. -** Derived, with permission, from the SOFA library. See notes at end of file. -*/ -{ - double v1[3], v2[3]; - -/* -** L2,B2 system of galactic coordinates in the form presented in the -** Hipparcos Catalogue. In degrees: -** -** P = 192.85948 right ascension of the Galactic north pole in ICRS -** Q = 27.12825 declination of the Galactic north pole in ICRS -** R = 32.93192 longitude of the ascending node of the Galactic -** plane on the ICRS equator -** -** ICRS to galactic rotation matrix, obtained by computing -** R_3(-R) R_1(pi/2-Q) R_3(pi/2+P) to the full precision shown: -*/ - double r[3][3] = { { -0.054875560416215368492398900454, - -0.873437090234885048760383168409, - -0.483835015548713226831774175116 }, - { +0.494109427875583673525222371358, - -0.444829629960011178146614061616, - +0.746982244497218890527388004556 }, - { -0.867666149019004701181616534570, - -0.198076373431201528180486091412, - +0.455983776175066922272100478348 } }; - - -/* Spherical to Cartesian. */ - eraS2c(dr, dd, v1); - -/* ICRS to Galactic. */ - eraRxp(r, v1, v2); - -/* Cartesian to spherical. */ - eraC2s(v2, dl, db); - -/* Express in conventional ranges. */ - *dl = eraAnp(*dl); - *db = eraAnpm(*db); - -/* 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. -** -*/ |