The construction of the opera glasses is unusually simple – these are so called Galilean binoculars in which a lens focuses light and an eye-piece diffuses it. Such glasses do not magnify the picture to a large extent, however, it is perfectly enough for a viewer who is in the hall to see what is going on at the stage of a theatre or an opera. A simple construction of optics is most frequently compensated with a stylish décor, which indeed turns these items into real pieces of art.
