Astronomy   View all facts   Glossary   Help

physical object > artifact > device > instrument > optical device > wavefront modifier > spectrograph dispersing element > diffraction grating > grism

grism comparison table

Subject	is a kind of	has definition
diffraction grating	spectrograph dispersing element	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.
grism	diffraction grating	This is a right-angled glass prism with a transmission diffraction grating deposited on the hypotenuse surface. The spectrum produced by the grating is deflected by the prism to remain on the optical axis and the apex angle of the prism is chosen to get a certain wavelength in the center of the detector. Grisms can be placed in a filter wheel.

Next diffraction grating: objective grating    Up: diffraction grating    Previous diffraction grating: echelle