In what year was the inventor of the Abbe prism born?
Ernst Abbe Ernst Karl Abbe HonFRMS (23 January 1840 – 14 January 1905) was a German physicist, optical scientist, entrepreneur, and social reformer. Together with Otto Schott and Carl Zeiss, he laid the foundation of modern optics. Abbe developed numerous optical instruments. He was a co-owner of Carl Zeiss AG, a German manufacturer of research microscopes, astronomical telescopes, planetariums and other optical systems.
Amici prism An Amici prism, named for the astronomer Giovanni Amici, is a type of compound dispersive prism used in spectrometers. The Amici prism consists of two triangular prisms in contact, with the first typically being made from a medium-dispersion crown glass, and the second a higher-dispersion flint glass. Light entering the first prism is refracted at the first air-glass interface, refracted again at the interface between the two prisms, and then exits the second prism at near-normal incidence. The prism angles and materials are chosen such that one wavelength (colour) of light, the "centre wavelength", exits the prism parallel to (but offset from) the entrance beam. The prism assembly is thus a "direct-vision prism", and is commonly used as such in hand-held spectroscopes. Other wavelengths are deflected at angles depending on the glass dispersion of the materials. Looking at a light source through the prism thus shows the optical spectrum of the source.