| Subject | 
has acronym | 
has definition | 
| diffraction grating |   | An optical device containing thousands of very fine parallel grooves which produce interference patterns in a way which separates out all the components of the light into a spectrum. | 
| Fabry-Perot interferometer | FP | A device that measures distances and changes of distance very accurately, using the pattern of overlap of waves of light. | 
| interference filter |   | A method of constructing an optical filter to select a particular wavelength band for transmission and reject wavelengths outside this band. Similar to a Fabry-Perot etalon. The construction relies on constructive and destructive interference effects in a multilayer stack of quarter-wave reflective layers and half-wave spacer layers. | 
| objective prism |   | A small-angle prism placed in front of a telescope objective to transform each star image in a field of stars into an image of its spectrum. |