The convex lens with large diameter and long focal length in front of telescope is called objective lens; A lens with a small diameter at the back and a short focal length is called an eyepiece. The objective lens condenses the light of the distant scene into an inverted and reduced real image at the back, which is equivalent to moving the distant scene closer to the imaging place at once. The inverted image of this scene just falls on the front focus of the eyepiece, so looking at the eyepiece is like looking at things with a magnifying glass, and you can see the virtual image magnified many times. In that case, the scenery far away seems to be close at hand in the telescope. Telescopes, like other optical instruments, have experienced a long history of development, and various types of telescopes have come out. According to the optical principle, it can be divided into two categories: refractive type and reflective type. Refractive binoculars, commonly known as prism binoculars, are often used in military and field investigation because of their short lens barrel, large field of view and convenient carrying. Reflective telescope is an eyepiece composed of concave mirror crop mirror and convex lens, which is used to observe celestial bodies in the Observatory.
The first person to apply for a patent for a telescope
The first person to get a patent for the telescope was Hans Lipsch, a Dutch optical instrument manufacturer, who applied for a patent at 1608. According to Lippert's telescope, Italian scientist Galileo made one himself in 1609. He improved his design and soon used it to study planets and stars.