The light chamber was a device designed by Prince Albert and George MacLeish to combat the threat of werewolves in the Scottish highlands. MacLeish built it by hand, spending much of his fortune to do so.
Most took it to simply be a telescope, as it had the appearance of one. However, if one attempted to use it in this manner, the image was out of focus.
The Eleventh Doctor kept the same device — or, possibly, either a copy, or a similarly looking telescope — in an observatory-like chamber in his TARDIS during the time he travelled with Clara Oswald. (TV: Journey to the Centre of the TARDIS)