Goniometers are used for high resolution angle measurements of surfaces with angular differences in excess of the range of an
autocollimator.  A precision rotary stage and encoder is combined with an electronic or visual autocollimator to make
measurements through 360°.

The Goniometer can be used for the precision measurement of refractive indices of transparent media in the UV-VIS-IR from
254nm - 2325nm.  Refractive index measurements are accurate to 1 in the 5th decimal place.  Liquids can be measured using a
special hollow prism.