Binoculars

**Binoculars** are simply small **refractors**. Binoculars are used to see distant objects. They allow us to see in **stereo**. They give superb wide-angle views of star-fields. Most good binoculars are better than **Galileo’s telescopes**.



There are two **prisms** arranged specially in each half of the binoculars.***Light rays from distant objects undergo total internal reflection in the prisms before entering the eyes of the observer***. The pair of prisms inside binoculars rotates the image through **180 degrees**. One prism rotates the image through **90 degrees**. Then the next prism flips it onto its side again, so the two prisms effectively turn it upside down. This process helps to solve problems with an image created by a convex lens.



When light rays from a distant object pass through a convex lens, they cross over. Binoculars are based on the science of optics and some very clever principles that lenses pull on light.