Is that were they stay all the time? I thought sun corals didn't like being in the light (I know, sounds strange considering the name). If that is where it has been and looks that good obviously your caring for it right.
General consensus used to be that they should be kept out of the light. During my research though, I noticed a few places stating it wasn't necessary. Like Grins said, they don't need the light to survive. Before I re-scaped it was in a slight cave and used to open up when lights went off. Since I've moved it here it opens up morning and night and sometimes during the day. So I'll let the pictures be the judge!!! (Oh and the fact I have baby ones popping up all over the tank!!!)
With regards to care, they're not that hard. You just have to target feed them every couple of days. I feed them with a mixture of mysis, krill and finely chopped mussel and try and put a piece in as many heads as possible.