CHESHIRE APERTOMETER

MAKER: BECK

c. EARLY 20th C.

The Cheshire Apertometer, a slight improvement over the Beck Apertometer, was also sold by Beck. It consisted of a glass disc with curved NA marks so as to make it easier to read at the edges of the field of the objective. A special eyepiece telescope was also sold to magnify the image at the back of the objective.