A prism has a constant cross-section throughout its length. When the cross-section is a triangle, the prism is called a triangular prism. When the cross-section is a hexagon, the prism is called a ...

Reader inquiries frequently concern the optimal binocular type for astronomical observation. Two primary binocular prism designs are distinguished: Porro prism and roof prism. Porro prism binoculars ...

Rotate and reverse images and deflect light at 90° bends. Suitable for telescopes and any optical instrument that requires the image to be flipped from the objective, turned over to the right, and ...