photoscope

from The Century Dictionary.

• noun An instrument or apparatus for exhibiting photographs.
• noun An instrument consisting of a selenium-cell, or an arrangement of some other substance whose electrical resistance varies with the degree of illumination, together with a telephone-receiver placed in the same electrical circuit, by means of which the varying intensities of light may be detected.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Physics) Anything employed for the observation of light or luminous effects.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Anything employed for the observation of light or luminous effects.