Compound achromatic microscope

Description

Coppock (1837-1900) was a partner of the well-known firm of Smith & Beck, he opened his own workshop in 1882.
The microscope has a horseshoe-shaped brass foot, filled with lead. On the foot a brass pillar with on top a compass joint, between which the upper part of the microscope can be inclined over 90 degrees. Coarse adjustment is by means of a sliding tube in a sleeve, lined with velvet. Fine adjustment is by a micrometer screw acting on the limb. The body tube is adjustable between 144 and 214 mm by means of a draw tube. The microscope has a simple square stage, on which a Leitz / Wetzlar mechanical stage is attached. Below the stage the concave mirror in a bracket, it can be moved out of the optical axis. Mounted is a paraboloid condenser with a concave front, when removed there is a simple revolving stop. Mounted on the limb in front of the microscope is a bull’s eye.
The microscope has a Huygenian eyepiece, its focal length is 22.67 mm, its magnification is 11.03×.
The objective is unsigned, it uses the standard RMS thread. There are three systems, the front in an adjustable tube, without a graduated correction collar.
It was investigated using the Bleeker microscope with a 160 mm body tube and a 5× Huygenian eyepiece: focal length 3.30 mm, magnification 252.6×, numerical aperture 0.55 and a resolving power less than 1 µm.