/*
* Copyright (C) 2021 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 .
*/
#ifndef ANTKEEPER_PHYSICS_TIME_UT1_HPP
#define ANTKEEPER_PHYSICS_TIME_UT1_HPP
#include "math/constants.hpp"
namespace physics {
namespace time {
/// Functions which operate on UT1 universal time.
namespace ut1 {
/**
* Calculates the Earth Rotation Angle (ERA) at a given UT1 date.
*
* @param t J2000 UT1 date.
* @return ERA at the given date, in radians.
*/
template
T era(T t);
template
T era(T t)
{
return math::two_pi * (T(0.7790572732640) + T(1.00273781191135448) * t);
}
} // namespace ut1
} // namespace time
} // namespace physics
#endif // ANTKEEPER_PHYSICS_TIME_UT1_HPP