💿🐜 Antkeeper source code https://antkeeper.com
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/*
* Copyright (C) 2020 Christopher J. Howard
*
* This file is part of Antkeeper source code.
*
* Antkeeper source code 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
* (at your option) any later version.
*
* Antkeeper source code 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 Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef ANTKEEPER_CELESTIAL_MECHANICS_HPP
#define ANTKEEPER_CELESTIAL_MECHANICS_HPP
#include "utility/fundamental-types.hpp"
namespace ast
{
/**
* Approximates the obliquity of the ecliptic.
*
* @param jd Julian date.
* @return Obliquity of the ecliptic, in radians.
*/
double approx_ecliptic_obliquity(double jd);
/**
* Approximates the ecliptic coordinates of the Earth's sun.
*
* @param jd Julian date.
* @return Ecliptic rectangular geocentric coordinates of the Earth's sun, with distance in AU.
*/
double3 approx_sun_ecliptic(double jd);
/**
* Approximates the ecliptic coordinates of the Earth's moon.
*
* @param jd Julian date.
* @return Ecliptic rectangular geocentric coordinates of the Earth's moon, with distance in Earth radii.
*/
double3 approx_moon_ecliptic(double jd);
/**
* Approximates the ecliptic rotation of the Earth's moon.
*
* @param jd Julian date.
* @return Rotation matrix representing the moon's rotation in ecliptic space.
*/
double3x3 approx_moon_ecliptic_rotation(double jd);
struct orbital_elements
{
double a; ///< Semi-major axis (km)
double e; ///< Eccentricity
double w; ///< Argument of periapsis (radians)
double m; ///< Mean anomaly (radians)
double i; ///< Inclination to the ecliptic (radians)
double n; ///< Longitude of the ascending node (radians)
};
//constexpr orbital_elements j2k_orbit_moon = {384400.0, 0.0554, 318.15, 135.275.16, 125.08};
struct orbital_state
{
double3 r; ///< Cartesian position
double3 v; ///< Cartesian velocity
};
} // namespace ast
#endif // ANTKEEPER_CELESTIAL_MECHANICS_HPP