Principle and optical path diagram of telescope.

Telescopes can enlarge the small opening angle of distant objects by a certain multiple, so that they have a larger opening angle in the image space, and make objects invisible or indistinguishable to the naked eye become clear and distinguishable. Telescope is an indispensable tool in astronomy and ground observation. Telescope is an optical system that keeps incident parallel beams parallel to each other through objective lens and eyepiece.

Optical path diagram of telescope;

According to the principle of telescope, it is generally divided into three types:

1. An instrument for observing electromagnetic radiation of distant objects by collecting electromagnetic waves is called a radio telescope.

2. In daily life, telescope mainly refers to optical telescope.

But 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.

Extended data:

1, 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.

2. The second function of the telescope is to send the light beam which is much thicker than the pupil diameter (up to 8 mm) collected by the objective lens to the human eye, so that the observer can see the dim objects that were not seen before.

The role of the telescope:

1, zoom in on the main body

When shooting wild animals and inaccessible objects, you must use a telescope, which is suitable for shooting the sunrise, sunset, moon and other celestial bodies.

2. Realize shallow depth of field

The telescope head has a long focal length, so the field of view is narrow and the scenery is deep. Using this feature of the telescope head, you can also shoot scenes, but not distant scenes, but near scenes suitable for the depth of field of the telescope head. Pay attention to the position of the foreground in the picture when composing, and improve the atmosphere of the picture by blurring the foreground. At this point, the photographer can give full play to his imagination.

3, compression, overlapping effect

By using the compression superposition effect of the telescope head, you can shoot the scenery, superimpose the near and medium-term prospects together, and depict the special effects that are difficult to see with the naked eye.

Using the compression overlapping effect of the telescope head, you can also photograph the flowers in the crown, which is a little far from the subject, and you can overlap the flowers full of trees layer by layer, showing a gorgeous effect. However, due to the shallow depth of field, attention should be paid to accurate focusing.

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