Long Keplerian binoculars
Keplerian binoculars became obsolete after Zeiss invented prism binoculars in the 1890s. They need to be long in order to have a lens inside to make the image appear upright. They were sometimes called twin telescopes.
Keplerian binoculars became obsolete after Zeiss invented prism binoculars in the 1890s. They need to be long in order to have a lens inside to make the image appear upright. They were sometimes called twin telescopes.
