Information about opera glasses

Opera glasses are also known as theatre binoculars or Galilean binoculars (named after the Italian astronomer Galileo Galilei who used the same structure for astronomical observation in 1609). They are compact, low-power optical magnification devices, usually used at opera, ballet and other performance events.

Crystar (Japan)

Crystar were founded in 1953, under the name Crystar Kōki KK Crystar manufactured cameras as well as optics.

Emil Busch AG (Germany)

Emil Busch AG was a prominent German company specialising in optical and precision instruments. The origins of the company date back to 1845, when Emil Busch, a pioneer in optics, took over a family business in Rathenow, Germany, focusing on the production of optical instruments