"The great equatorial telescope in the Dome at Greenwich." Illustrated London News. Royal Observatory, Greenwich, London, England. This is the 12.75-inch Merz telescope, which was used for planetary observations. The mount is an equatorial mount, helping astronomers to accurately track stars and planets across the sky. This telescope, made by Merz of Germany, was mounted on this base in 1859. This telescope was replaced in 1893 by a larger telescope, the famous 28-inch refractor.