optical (optics) instrument maker who invented the telescope (Schmidt telescope) named for him, an instrument widely used to photograph large sections of the sky because of its large field of view and its fine image definition.

Schmidt worked as a telegraph operator, photographer, and designer until 1898. In 1901 he went to the engineering school at Mittweida, Germany, to study and remained there until 1926 to install a small workshop and observatory. The parabolic mirrors and the 16-inch telescope he made during this time established his reputation as an optical technician.

In 1926 Schmidt joined the staff of the Hamburg Observatory, Bergedorf, and three years later he conceived a new mirror system for telescopes. All previous reflecting telescopes designed to view large areas were subject to image defects, particularly the type known as spherical aberration when spherical mirrors were used, and to a type of blurring of the image, known as coma, even a short way off the optical axis if parabolic mirrors were used. Schmidt succeeded in designing a telescope in which these distortions were eliminated by a combination of a specially figured lens and a spherical mirror placed some distance behind it.