Square section terrestrial telescope, c. 1745.

Square section terrestrial telescope with brass quadrant and mahogany bracket

Square section terrestrial telescope, c. 1745. This telescope, with a brass quadrant and a mahogany bracket, was made by William Robertson, who was primarily a microscope maker. It was probably used by Dr. Stephen Demainbray (1710-1782), a lecturer in experimental philosophy, in his lecture on the construction of telescope.