Napoleon Carreau (Score 2, Interesting)

In this article, it says the mirror for the telescope was ground by the astronomer himself. However, in my family it has always been said that the LENS in the telescope used to discover Pluto was ground by my great-grandfather, Napoleon Carreau. I know nothing about astronomy or the history book version of Pluto's discovery, so I'm a little confused. I was also under the impression that the "planet X" telescope was in a museum right now. Is it possible that this telescope uses a lense in addition to a mirror? Or perhaps that the telescope my great-grandfather helped make was a completely different one? Or something else that I'm not considering?