What is the diameter of the eyepiece of the telescope?

The diameter of the eyepiece of a telescope is called inches. ?

The diameter of the eyepiece of most telescopes is 1.25 inch (3 1.75mm), and the actual upper limit of the focal length of the eyepiece with this diameter is about 32 mm. The eyepiece with longer focal length, the eyepiece with focal length longer than 32 mm, and the edge of the lens barrel diameter limit the size of the field of view to less than 50, which is the minimum field of view that most amateurs think is acceptable. A 30 mm filter can be placed in this cylindrical diameter spiral.

An eyepiece with a barrel diameter of 50.8 mm is often used. The focal length limit of 2-inch eyepiece is about 50mm, and the diameter of lens barrel larger than 2 inches (50.8 mm) is mainly used to help expand the focal length limit of eyepiece. This kind of eyepiece is usually expensive, and it may be so heavy that the telescope is overturned.

Extended data

Telescope is a visual optical instrument used to observe distant objects. It can enlarge the small opening angle of distant objects according to a certain proportion, so that they have a larger opening angle in the image space, and make the objects that were invisible or unclear to the naked eye become clear.

Therefore, the telescope is an indispensable tool in astronomy and ground observation. It is an optical system that makes the incident parallel beams pass through the objective lens and eyepiece and still exit in parallel.

According to the principle of telescope, it is generally divided into three types. An instrument for observing electromagnetic radiation of distant objects by collecting electromagnetic waves is called a radio telescope. In daily life, telescopes mainly refer to optical telescopes.

In modern astronomy, astronomical telescopes include radio telescopes, infrared telescopes, X-ray telescopes and gamma-ray telescopes. The concept of astronomical telescope has been further extended to gravitational waves, cosmic rays, dark matter and other fields.

References:

Baidu encyclopedia-telescope