|MadSci Network: Astronomy|
The "angle of minimum deviation" method (Schuster's method) was first based on the observation that when turning a face of a prism in front of a light source, the refracted light transmitted by the prism reaches a minimum angle of "deflection" with respect to the incident beam. That means the angle of deviation is always bigger on either side of this minimum. Since prisms can disperse light, it was also seen that each wavelength of light has its own specific minimum angle of deviation. It was determined that one could find the index of refraction of a tranparent material easily by this method. Rather than write down the equation you would need to do this, I've got a handy URL for you using this "prism equation" demonstrating the angle of deviation in this way.
I am a bit confused by utilizing this method for setting up a diffraction grating spectrometer and your short description. Hmmm. If you could describe the experiment further I might be of better assistances.
---* Dr. Ken Beck
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