hello everyone! this is a new single-dish radio telescope, FAST, under construction: http://nextbigfuture.com/2011/06/chinas-five-hundred-meter-aperture.html The aperture is 500 m. But the illuminated aperture is only 300m. So what is the advantage of bigger aperture? is the angular resolution 1.22*wavelegth/300 or 500? if it is 300 so what is the preference of bigger aperture?