In spectroscopic observations, sometimes you meet grism, sometimes grating.
Both of them could cause light dispersion, but what is the difference?
$\begingroup$
$\endgroup$
3
-
$\begingroup$ Grism: en.wikipedia.org/wiki/Grism $\endgroup$– Wayfaring StrangerApr 21 '15 at 10:45
-
$\begingroup$ I know that link. What is the function of a prism? A prism itself is enough to disperse light. $\endgroup$– questionhangApr 21 '15 at 11:04
-
1$\begingroup$ They disperse light with different dispersion functions, allowing astronomers to see different spectral features. $\endgroup$– Donald.McLean ♦Apr 21 '15 at 11:29
Add a comment
|
$\begingroup$
$\endgroup$
Transmission gratings on their own introduce chromatic aberration. This is because they change the effective focal length and do so as a function of wavelength. The chromatic aberration can be eliminated by introducing a prism of the correct dispersion. Known as a grism, the grating/prism combination provides an unaberrated image at the 0th order in addition to the spectrum, although the spectrum has fairly low resolution.
