public static void calc_geocentric(ref double longitude, ref double latitude, ref double rektaszension, ref double declination, double date) { //var double epsilon; //: extended; double delta_phi; //: extended; double alpha, delta; //: extended; calc_epsilon_phi(date, out delta_phi, out epsilon); longitude = GPMath.putIn360(longitude + delta_phi); alpha = GPMath.arctan2Deg(GPMath.sinDeg(longitude) * GPMath.cosDeg(epsilon) - GPMath.tanDeg(latitude) * GPMath.sinDeg(epsilon), GPMath.cosDeg(longitude)); delta = GPMath.arcsinDeg(GPMath.sinDeg(latitude) * GPMath.cosDeg(epsilon) + GPMath.cosDeg(latitude) * GPMath.sinDeg(epsilon) * GPMath.sinDeg(longitude)); rektaszension = alpha; declination = delta; double xg, yg, zg; xg = GPMath.cosDeg(longitude) * GPMath.cosDeg(latitude); yg = GPMath.sinDeg(longitude) * GPMath.cosDeg(latitude); zg = GPMath.sinDeg(latitude); alpha = GPMath.arctan2Deg(yg * GPMath.cosDeg(epsilon) - zg * GPMath.sinDeg(epsilon), GPMath.cosDeg(longitude) * GPMath.cosDeg(latitude)); }