Sky Dome

Whilst replacing a bulb in a sun pipe, I took this photo looking up the pipe out to the roof light. When I first removed the cover in the room and looked up, my brain was quite disorientated for a few seconds until it worked out what it was seeing.

For those who are not familiar with these devices they allow daylight into a room where the roof is not directly accessible and can transform a dark room. They have a light bulb for night time and so can also double as a room light. They are known by various names such as sky dome, sun pipe, light pipe. See Wikipedia under "light pipe" for more information.