I was fortunate to be at the Tate for that exhibition and got to see when they turned the 'sun' off at closing time. I was visiting my brother in London at the time, he wasn't a big fan of modern art, so we split up, I went to the Tate, he went elsewhere to sight see, then later at dinner after effusing over the 'sun' exhibit and showing him photos of how cool it was, we rushed across town to get in just before closing. We got to see it together for about 10 minutes, before they turned it off. It went from a Sun to the Moon. Spectacular.