Abbe, Ernst (1840–1905)

German physicist who, working with Carl Zeiss, greatly improved the design and quality of optical instruments, particularly the compound microscope. This enabled researchers to observe micro-organisms and internal cellular structures for the first time.

Abbe was born in Eisenach, Thuringia, and studied physics at Jena and Göttingen, becoming a professor at Jena 1870 and director of the observatory 1878. Zeiss supplied optical instruments to the university and repaired them. Abbe became a partner in Zeiss's firm.

Abbe worked out how to overcome spherical aberration in lenses and why, contrary to expectation, the definition of a microscope decreases with a reduction in the aperture of the objective; he found that the loss in resolving power is a diffraction effect. In 1872 he developed the Abbe substage condenser for illuminating objects under high-power magnification.