Here are two shots of the 15" (381mm) mirror, which is about f6. As you can see, it needed re-aliminising, and this has been done (see later pages).

Notice the extraordinary thickness of the mirror. Patrick is not sure who made the mirror originally, but it was re-figured by the great British mirror maker George Hole, who lived in Brighton. I am fortunate enough to own a 200mm mirror made by George Hole in the early 1970s.