It is an optical instrument that uses optical devices such as lenses or mirrors to observe distant objects. It uses the refraction of light through a lens or the reflection of light by concave mirror to make it enter a small hole and converge to form an image, and then it is seen through a magnifying eyepiece, also known as a "thousand-mile mirror".
The first function of the telescope is to enlarge the opening angle of distant objects, so that the human eye can see the details with smaller angular distance. The second function of the telescope is to send the light beam collected by the objective lens, which is much thicker than the pupil diameter (up to 8 mm), to the human eye, so that the observer can see dim objects that he could not see before.
1608, Hans Lippershey, an optician in middelburg, the Netherlands, built the world's first telescope. Once, two children played some scenes in front of Lipper's shop. They looked at the weather vane on the distant church through the front and rear lenses and were in high spirits. Liporsay picked up two lenses and saw that the weather vane in the distance was greatly enlarged.
Lippert ran back to the store and put the two lenses on a spool. After many experiments, Hans Lippert invented the telescope. 1608, he applied for a patent for his telescope, and made a binoculars according to the requirements of the authorities. It is said that dozens of telescope opticians in the town all claimed to have invented the telescope.