1 /* 2 * - - - - - - - - - - - - 3 * g a l _ b j u p v 8 7 4 * - - - - - - - - - - - - 5 * 6 * This routine is part of the General Astrodynamics Library 7 * 8 * Description: 9 * 10 * Jupiter barycentric position and velocity, with respect to the 11 * FK5 Reference Frame. 12 * 13 * Status: 14 * 15 * internal support routine. 16 * 17 * Given: 18 * 19 * tt1 d TT epoch part 1 (Note 1) 20 * tt2 d TT epoch part 2 (Note 1) 21 * ref i Reference frame 22 * 0 = dynamical equinox and ecliptic J2000. 23 * 1 = FK5 (VSOP87) 24 * 25 * Returned: 26 * 27 * pv d[2][3] position/velocity (AU, AU/Day) 28 * 29 * Called: 30 * 31 * gal_vsop87 Compute VSOP87 position and velocity 32 * 33 * Notes: 34 * 35 * 1) The epoch tt1+tt2 is a Julian Date, apportioned in 36 * any convenient way between the two arguments. For example, 37 * JD(TDB)=2450123.7 could be expressed in any of these ways, 38 * among others: 39 * 40 * tt1 tt2 41 * 42 * 2450123.7 0.0 (JD method) 43 * 2451545.0 -1421.3 (J2000 method) 44 * 2400000.5 50123.2 (MJD method) 45 * 2450123.5 0.2 (date & time method) 46 * 47 * The JD method is the most natural and convenient to use in 48 * cases where the loss of several decimal digits of resolution 49 * is acceptable. The J2000 method is best matched to the way 50 * the argument is handled internally and will deliver the 51 * optimum resolution. The MJD method and the date & time methods 52 * are both good compromises between resolution and convenience. 53 * However, the accuracy of the result is more likely to be 54 * limited by the algorithm itself than the way the epoch has been 55 * expressed. 56 * 57 * 2) On return, the arrays pvh and pvb contain the following: 58 * 59 * pv[0][0] x } 60 * pv[0][1] y } position, AU 61 * pv[0][2] z } 62 * 63 * pv[1][0] xdot } 64 * pv[1][1] ydot } velocity, AU/day 65 * pv[1][2] zdot } 66 * 67 * The vectors are barycentric with respect to the FK5 Reference Frame. 68 * The time unit is one day in TT 69 * 70 * 3) The routine is a soution from the planetary theory VSOP87 71 * 72 * 4) The main version of VSOP87 is similar to the previous theory VSOP82. 73 * In the both cases the constants of integration have been determined by 74 * fitting to the numerical integration DE200 of the Jet Propulsion Laboratory. 75 * 76 * The differences between VSOP87 and VSOP82 mainly improve the validity time-span 77 * for Mercury, Venus, Earth-Moon barycenter and Mars with a precision of 1" for 78 * 4000 years before and after J2000. 79 * The same precision is ensured for Jupiter and Saturn over 2000 years and for 80 * Uranus and Neptune over 6000 years before and after J2000. 81 * 82 * The size of the relative precision p0 of VSOP87 solutions is given hereunder. 83 * That means that the actual precision is close by p0*a0 au for the distances 84 * (a0 being the semi-major axis) and close by p0 radian for the other variables. 85 * By derivation with respect to time expressed in day (d), the precision of the 86 * velocities is close by p0*a0 au/d for the distances and close by p0 radian/d 87 * for the other variables. 88 * 89 * Body a0 (au) p0 (10**-8) 90 * ---- ------- ----------- 91 * Mercury 0.3871 0.6 92 * Venus 0.7233 2.5 93 * Earth 1.0000 2.5 94 * Mars 1.5237 10.0 95 * Jupiter 5.2026 35.0 96 * Saturn 9.5547 70.0 97 * Uranus 19.2181 8.0 98 * Neptune 30.1096 42.0 99 * 100 * References: 101 * 102 * Bretagnon P., Francou G., : 1988, Astron. Astrophys., 202, 309. 103 * 104 * This revision: 105 * 106 * 2008 June 29 107 * 108 * Copyright (C) 2008 Paul C. L. Willmott. See notes at end. 109 * 110 *----------------------------------------------------------------------- 111 */ 112 113 #ifndef _GAL_BJUPV87_H_ 114 #define _GAL_BJUPV87_H_ 1 115 116 #undef __BEGIN_DECLS 117 #undef __END_DECLS 118 #ifdef __cplusplus 119 #define __BEGIN_DECLS extern "C" { 120 #define __END_DECLS } 121 #else 122 #define __BEGIN_DECLS /* empty */ 123 #define __END_DECLS /* empty */ 124 #endif 125 126 __BEGIN_DECLS 127 128 void 129 gal_bjupv87 130 ( 131 double tt1, 132 double tt2, 133 int ref, 134 double pv[2][3] 135 ) ; 136 137 __END_DECLS 138 139 #endif /* !_GAL_GAL_BJUPV87_H_ */ 140 141 /* 142 * gal - General Astrodynamics Library 143 * Copyright (C) 2008 Paul C. L. Willmott 144 * 145 * This program is free software; you can redistribute it and/or modify 146 * it under the terms of the GNU General Public License as published by 147 * the Free Software Foundation; either version 2 of the License, or 148 * (at your option) any later version. 149 * 150 * This program is distributed in the hope that it will be useful, 151 * but WITHOUT ANY WARRANTY; without even the implied warranty of 152 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 153 * GNU General Public License for more details. 154 * 155 * You should have received a copy of the GNU General Public License along 156 * with this program; if not, write to the Free Software Foundation, Inc., 157 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 158 * 159 * Contact: 160 * 161 * Paul Willmott 162 * vp9mu@amsat.org 163 */ 164