Image formation through monoaxial plane-parallel plates.
A quantitative study of the formation of images through plane-parallel plates of a monoaxial birefringent material has been performed. Formulas for the transverse and longitudinal displacements of the image have been obtained, and it is shown that a first-order astigmatism appears which is due exclusively to the anisotropy of the crystal. An exact calculation by ray tracing proves that the approximate formulas are satisfactory.