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core/planetsephems/gust86.h

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