The planetarium itself is a rather expensive experience, guided by knowledgeable experts, located in a specially designed room. I had promised my son a visit here while in London and he was very satisfied with the whole experience. My interest was maintained up until the point the guide told us to close our eyes and feel what it is like to be in darkness. At this point, because I was rather tired by that time I admit that I had a snooze in the overly comforatble chairs, waking up every now and then to an interesting sight on the ceiling which my son explained to me afterwards. But a visit to the planetarium can be combioned with many of the other activities offered in the same general area, and they are really worthwhile - which is why a visit to the planetarium is not a 1-hour affair, because you will be tempted to stay on for much longer.