ProperMotion.h

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// -*- LSST-C++ -*-
/*
 * This file is part of jointcal.
 *
 * Developed for the LSST Data Management System.
 * This product includes software developed by the LSST Project
 * (https://www.lsst.org).
 * See the COPYRIGHT file at the top-level directory of this distribution
 * for details of code ownership.
 *
 * 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
 * (at your option) 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 <https://www.gnu.org/licenses/>.
 */
 
#ifndef LSST_JOINTCAL_PROPER_MOTION_H
#define LSST_JOINTCAL_PROPER_MOTION_H
 
#include <cmath>  // atan2
#include <iostream>
#include <memory>
 
namespace lsst {
namespace jointcal {
 
class Point;

class ProperMotion {
public:
    ProperMotion(double ra, double dec, double raErr, double decErr, double raDecCov = 0)
            : _ra(ra), _dec(dec), _raErr(raErr), _decErr(decErr), _raDecCov(raDecCov) {
        _offsetBearing = atan2(dec, ra);
    };
 
    ProperMotion(ProperMotion const &) = default;
    ProperMotion(ProperMotion &&) = default;
    ProperMotion &operator=(ProperMotion const &) = default;
    ProperMotion &operator=(ProperMotion &&) = default;
    ~ProperMotion() = default;

    Point apply(const Point& star, double timeDeltaYears) const;
 
    friend std::ostream &operator<<(std::ostream &stream, ProperMotion const &pm);
 
private:
    // Proper motion in ra and dec. Units are radians/year
    double _ra, _dec;
    double _raErr, _decErr, _raDecCov;
 
    // Cache the bearing along-which to offset.
    double _offsetBearing;
};
}  // namespace jointcal
}  // namespace lsst
 
#endif  // LSST_JOINTCAL_PROPER_MOTION_H