Schuster's is the best method of focusing the telescope and the collimator for parallel/paraxial rays within the space available in the dark room. Place the prism . Let the angle of incidence at minimum deviation be imin. For a prism the graph of angle of deviation against angle of incidence looks something. two horizontal steel rails; U1 is the upright carrying the slit S, U2 is the upright . Focusing for parallel rays: Schuster's method: This is the best method of. Schuster's method (details of which is given in another experiment). Details about reading angles in spectrometer are given in the manual for finding angle of . Shuster. 3The transition to a more normal personal life has been gradual. In the TRIAD method, invented in by Harold D. Black , one is given two. The diffraction pattern due to a grating is essentially the same as the diffraction . is done by the so called Schuster's method. First, the entrance slit of the. Appendix: Support manual for prism spectrometer. In some of the . (vi) Focusing for Parallel rays by Schuster's method: This is the best method of focusing the. let me give the schusters method in brief: Focus the eye piece of the telescope on the cross wires and do not disturb this adjustment here after. Obtaining the slit image in the field of view the table carrying the prism is slowly rotated. It is observed that the image moving in one direction suddenly reverses.