Okay,.....this is all well and good, but be forwarned, this method takes a fair amount of render time, even on normal setting. And you may have to tweak the dome yourself to get exactly the effect you want. It does however produce very nice results. I have used it in several images recently. Do an author search for sackrat and look at the image "Sax and Edison" This image was my first using this method, hence the simplicity. But it's pretty trick as far as the final render, just be prepared to wait for the results.

"Any club that would have me as a member is probably not worth joining" -Groucho Marx