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/*
* orbital_elements.h - Declarations for orbital element support
* Copyright (C) 2010 Shiva Iyer <shiva.iyer AT g m a i l DOT c o m>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _ORBITAL_ELEMENTS_H_
#define _ORBITAL_ELEMENTS_H_
#include "kepler.h"
#include "julian_date.h"
#include "coordinate.h"
#define PARABOLIC_ORBIT 1.00
#define KEPLER_MAX_ITER 10
#define KEPLER_PRECISION 1e-14
/*
* Used wherever the osculating orbital elements of a celestial body are
* expected or returned.
*
* These values may be obtained from the circulars of the Minor Planet
* Center, the Astronomical Almanac or other publications. See mpc_file.c
* for some ways in which this structure is used.
*/
struct orbital_elements {
struct julian_date epoch; /* Epoch of osculation. */
double mean_anomaly; /* Mean anomaly in radians at epoch. */
double daily_motion; /* Daily motion in radians/day. */
double perihelion; /* Perihelion distance in AU. */
double eccentricity; /* Eccentricity of the orbit. */
/* The values for the orbit's orientation must be referred to J2000. */
double arg_perihelion; /* Argument of the perihelion in radians. */
double lon_asc_node; /* Longitude of the ascending node in radians. */
double inclination; /* Inclination of the orbit in radians. */
};
/*
* May be set to limit the number of iterations in the solution of Kepler's
* equations. The default value is KEPLER_MAX_ITER.
*/
extern u_short kepler_equation_max_iters;
/*
* May be set to specify the precision expected in the solution Kepler's
* equations. The default value is KEPLER_PRECISION.
*/
extern double kepler_equation_precision;
#ifdef _DEBUG
/*
* Set to the number of iterations required for the solution of Kepler's
* equations in the most recent call to the relevant functions.
*/
extern u_short kepler_equation_iters;
#endif
int elements_to_ephemeris(struct julian_date *tt, struct orbital_elements *elt,
struct rectangular_coordinates *eph);
int eccentric_anomaly(double mean_ano, double ecc, double *ecc_ano);
int hyperbolic_anomaly(double mean_ano, double ecc, double *hyp_ano);
#endif
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