Ernst Karl Abbe was a German physicist, optical scientist, entrepreneur, and social reformer. His theoretical and technical innovations in optical theory led to great improvements in microscope design and a clearer understanding of magnification limits.

Together with Otto Schott and Carl Zeiss, he developed numerous optical instruments. He was also a co-owner of Carl Zeiss AG, a German manufacturer of scientific microscopes, astronomical telescopes, planetariums, and other advanced optical systems.

In 1873 he discovered the optical formula now called the Abbe sine condition, one of the requirements that a lens must satisfy if it is to form a sharp image, free from the blurring or distortion caused by coma and spherical aberration. The crater Abbe on the Moon was named in his honour.

To honour his contribution, German Postal Department has issued a stamp depicting microscope.

Image Source: Wikipedia.org