Cassegrain reflecting telescope of 6 inch aperture by Jesse Ramsden (~1762-1774).
Science Museum Group, CC BY-SA 4.0 via Cassegrain reflecting telescope, 1762-1774. 1913-281 Science Museum Group Collection Online. collection.sciencemuseumgroup.…
Cassegrain reflecting telescope, 1762-1774 | Science Museum Group Collection
Cassegrain reflecting telescope of 6 inch aperture by Jesse Ramsden, London on an adjustable equatorial mounting with 2 spirit levels and 3 levelling screws.collection.sciencemuseumgroup.org.uk