The biggest in the World, apparently, and one of those bonkers ideas that the French seem to do with a flair others can't match. What you see here is the 'concentrator' which receives sunlight reflected from mirrors on a hill opposite.The concentrator mirrors reflect this light onto a target 40cm in diameter located in the building in front. This can reach temperatures of upto 3,500 °C, and is used for testing and developing advanced materials. Hotter than hell? Hopefully I'll never find out.
@granagringa The lens was a very simple accessory for Olympus cameras, a fixed aperture lens with a 9mm focal length that replaces the body cap. and gives the slight fisheye effect you noticed.
