The William Herschel Telescope
The William Herschel Telescope at sunset. . The William Herschel Telescope was for many years the biggest and best optical telescope in Europe (until GranTeCan opened in 2009). The main mirror is 4.2 m across (165″, or 13′ 9″) which astronomers call “a good light bucket”. It’s rather old as world-class telescopes go, since it opened in 1987, but it still produced excellent science. In fact data from the WHT…