Universal stereoscope

A universal stereoscope is a viewer that allows different stereoview formats to be observed. These are typically open viewers that are not constrained by an enclosed housing designed for a specific stereo format. Different formats can be placed on a plate that is only limited by the largest supported format, as in Ernemann's Universal-Stereobetrachter, or they are inserted into a holder.

Universal stereoscopes are not regarded as a distinct stereoscope type, but occur within existing type classifications.