Title: 4mm Apochromatic Objective with Correction Collar

Identifier: LL02.48.06.20   (https://digital.lib.ecu.edu/22067)

Description: Abbe developed objectives that corrected spherical aberration for two colors as well as the achromatic corrections during the 1880's. The higher powers also required correction for the cover glass thickness. This objective has a magnification of about 63X. Apochromatic objectives are still manufactured. The photograph also includes two other Zeiss apochromatic lenses manufactured in the early twentieth-century around 1935.