phaseAngle3 function
Phase angle from heliocentric ecliptic + cartesian.
Implementation
double phaseAngle3(double lon, double lat,
double x, double y, double z, double delta) {
final sL = math.sin(lon), cL = math.cos(lon);
final sB = math.sin(lat), cB = math.cos(lat);
return math.acos((x * cB * cL + y * cB * sL + z * sB) / delta);
}