Monocular

A monocular is a modified refracting telescope used to magnify the images of distant objects by passing light through a series of lenses and sometimes prisms; the use of prisms results in a lightweight telescope. Volume and weight are less than half those of binoculars of similar optical properties, making it easy to carry. Monoculars produce 2-dimensional images, while binoculars add perception of depth (3 dimensions).