just in case you want to post-mortemly (post-work'ly?) add a halo around that perfectly round Sun, with animated streams and a halo, even tracking the motion of the sun through a few keyframes as the camera moves, here's something I did: www.thebest3d.com/carrara/spaceship > look towards the bottom, where the Sunwent from similar to yours to glary and animated streaks. Sometimes one forgets about the visual fx you wanted and a few hours or days of rendering later you wonder how you could make it more what you had in mind.