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00001 /************************************************************************ 00002 00003 COMPUTATION OF THE COORDINATES OF THE URANIAN SATELLITES (GUST86), 00004 version 0.1 (1988,1995) by LASKAR J. and JACOBSON, R. can be found at 00005 ftp://ftp.imcce.fr/pub/ephem/satel/gust86 00006 00007 I (Johannes Gajdosik) have just taken the Fortran code and data 00008 obtained from above and rearranged it into this piece of software. 00009 00010 I can neigther allow nor forbid the usage of the GUST86 theory. 00011 The copyright notice below covers not the works of LASKAR J. and JACOBSON, R., 00012 but just my work, that is the compilation of the GUST86 theory 00013 into the software supplied in this file. 00014 00015 00016 Copyright (c) 2005 Johannes Gajdosik 00017 00018 Permission is hereby granted, free of charge, to any person obtaining a 00019 copy of this software and associated documentation files (the "Software"), 00020 to deal in the Software without restriction, including without limitation 00021 the rights to use, copy, modify, merge, publish, distribute, sublicense, 00022 and/or sell copies of the Software, and to permit persons to whom the 00023 Software is furnished to do so, subject to the following conditions: 00024 00025 The above copyright notice and this permission notice shall be included 00026 in all copies or substantial portions of the Software. 00027 00028 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 00029 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 00030 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 00031 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 00032 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 00033 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 00034 SOFTWARE. 00035 00036 My implementation of GUST86 has the following modifications: 00037 1) Rotate results to "dynamical equinox and ecliptic J2000", 00038 the reference frame of VSOP87 and VSOP87A: 00039 The rotation matrix Gust86ToJ2000 can be derived from gust86.f, 00040 the rotation J2000ToVsop87 can be derived from vsop87.doc. 00041 2) units used in calculations: julian day, AU, rad 00042 3) use the same function EllipticToRectangular that I use in TASS17. 00043 4) calculate the orbital elements not for every new jd but rather reuse 00044 the previousely calculated elements if possible 00045 00046 ****************************************************************/ 00047 00048 00049 #ifndef _GUST86_H_ 00050 #define _GUST86_H_ 00051 00052 #ifdef __cplusplus 00053 extern "C" { 00054 #endif 00055 00056 #define GUST86_MIRANDA 0 00057 #define GUST86_ARIEL 1 00058 #define GUST86_UMBRIEL 2 00059 #define GUST86_TITANIA 3 00060 #define GUST86_OBERON 4 00061 00062 void GetGust86Coor(double jd,int body,double *xyz); 00063 /* Return the rectangular coordinates of the given satellite 00064 and the given julian date jd expressed in dynamical time (TAI+32.184s). 00065 The origin of the xyz-coordinates is the center of the planet. 00066 The reference frame is "dynamical equinox and ecliptic J2000", 00067 which is the reference frame in VSOP87 and VSOP87A. 00068 00069 According to vsop87.doc VSOP87 coordinates can be transformed to 00070 FK5 (=J2000=ICRF for our accuracy requirements) by 00071 X cos(psi) -sin(psi) 0 1 0 0 X 00072 Y = sin(psi) cos(psi) 0 * 0 cos(eps) -sin(eps) * Y 00073 Z FK5 0 0 1 0 sin(eps) cos(eps) Z VSOP87 00074 with psi = -0.0000275 degrees = -0.099 arcsec and 00075 eps = 23.4392803055556 degrees = 23d26m21.4091sec. 00076 00077 http://ssd.jpl.nasa.gov/horizons_doc.html#frames says: 00078 "J2000" selects an Earth Mean-Equator and dynamical Equinox of 00079 Epoch J2000.0 inertial reference system, where the Epoch of J2000.0 00080 is the Julian date 2451545.0. "Mean" indicates nutation effects are 00081 ignored in the frame definition. The system is aligned with the 00082 IAU-sponsored J2000 frame of the Radio Source Catalog of the 00083 International Earth Rotational Service (ICRF). 00084 The ICRF is thought to differ from FK5 by at most 0.01 arcsec. 00085 00086 From this I conclude that in the context of stellarium 00087 ICRF, J2000 and FK5 are the same, while the transformation 00088 ICRF <-> VSOP87 must be done with the matrix given above. 00089 */ 00090 00091 void GetGust86OsculatingCoor(double jd0,double jd,int body,double *xyz); 00092 /* The oculating orbit of epoch jd0, evatuated at jd, is returned. 00093 */ 00094 00095 #ifdef __cplusplus 00096 } 00097 #endif 00098 00099 #endif