* @param b
* @return The visible angle (in rad) between two stars
*/
@Override
public double get(Astre a, Astre b) {
UserCoordinates uc = ((SkyMap) Front.userInterface.getSkyMap()).getUserCoordinates();
LocalHorizontalCoordinates ac = Coordinates.equatorialToLocalHorizontal(a.getCoodinates(), uc);
LocalHorizontalCoordinates bc = Coordinates.equatorialToLocalHorizontal(b.getCoodinates(), uc);
// double x = 2*Math.sin(Math.abs(ac.getHauteur() - bc.getHauteur())/2);
// double y = 2*Math.sin(Math.abs(ac.getAzimut() - bc.getAzimut())/2);
double x = Math.abs(ac.getHauteur() - bc.getHauteur());