phaseAngleEcl function

double phaseAngleEcl(
  1. double lon,
  2. double lat,
  3. double delta,
  4. double lon0,
  5. double r,
)

Phase angle from ecliptic coordinates.

Implementation

double phaseAngleEcl(double lon, double lat, double delta,
    double lon0, double r) {
  final cPsi = math.cos(lat) * math.cos(lon - lon0);
  final sPsi = math.sin(math.acos(cPsi));
  return math.atan2(r * sPsi, delta - r * cPsi);
}