A grism is a combination of a prism and grating arranged to keep light at a chosen central wavelength undeviated as it passes through. In Optics, a prism is a transparent optical element with flat polished surfaces that refract Light. In Optics, a Diffraction grating is an optical component with a regular pattern which splits ( diffracts) light into several beams travelling in different Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency.
The resolution of a grism is proportional to the tangent of the wedge angle of the prism in much the same way as the resolutions of gratings are proportional to the angle between the input and the normal to the grating. Angular resolution describes the resolving power of any image forming device such as an optical or Radio telescope, a Microscope, a Camera
Grisms are normally inserted into a collimated camera beam. Collimated light is Light whose rays are nearly parallel and therefore will spread slowly as it propagates The grism then creates a dispersed spectrum centered on the location of the object in the camera field of view. In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency A spectrum (plural spectra or spectrums) is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The field of view (also field of vision) is the angular extent of the observable world that is seen at any given moment
Source
Space Telescope Science Institute
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic