I want to buy an astronomical telescope and give me some advice. Experts come in! !

In outdoor activities, such as exploration, hunting, surveying, traveling, etc., it would be great if you have a satisfactory telescope in your hand. Currently, there are many types of telescopes sold in the domestic market. But in general, it can be divided according to the following aspects:

Divided according to different places of origin, including foreign (Russia, Japan, the United States, Germany, etc.), domestic (Guangdong, Zhejiang, Sichuan, etc.) Shanghai, etc.); adventure brands are divided into different brands, including Xianlifu, Powerlong, Debao, Sakura, Kenco, Golden Triangle, etc.; they are divided according to different uses, including variable power mirrors, waterproof mirrors, and night vision goggles; and they are divided according to magnification. Divided into low multiples (2 to 5 times, mostly found in toy products), medium multiples (7 to 10 times), and high multiples (15 to 70 times). When people buy telescopes, they often see several Arabic numerals on the price list. So what technical parameters do these numbers indicate? Let’s give an example to illustrate. For example, if it is marked 10×50mm5°, it means that the magnification is 10 times, the diameter of the objective lens is 50 mm, and the field of view is 5 degrees (that is, the field of view width at 1000 is 87.4 meters). The following is a more detailed introduction to each function:

Aperture of the telescope: The larger the aperture, the larger the observation field and brightness, which is conducive to observation in dim light, but the larger the aperture, the larger the size. The greater the importance, the higher the cost, and the inconvenience of carrying. Generally, you can choose between 30-50mm according to needs.

Field of view: The field of view refers to the observable horizon at a kilometer, such as 1000/93m, which means that the telescope can observe a 93-meter-wide range at a kilometer, which can also be converted into " degree" expressed as 5°30′. The comparison of field of view must be done under the conditions of similar aperture and the same magnification. The key to the size of the field of view lies in the design of the eyepiece part of the prism system. Generally, high-end varieties and military telescopes from famous manufacturers adopt wide-angle and large-field designs. This wide-angle A large field of view telescope will give people a feeling of spaciousness, comfort, and relaxation.

Coating: The function of lens coating is to reduce reflection, increase light transmittance, and improve observation brightness. Different coating colors have nothing to do with quality. The lighter the coating, the smaller the reflection, the better. However, in recent years, various red and yellow telescopes with strong reflections and bright colors have appeared on the market, which are very attractive to consumers. In fact, this kind of inferior coating A lot of light is lost due to reflection, making the colors colder and darker, and the clarity reduced. What's more, some people actually deceive consumers by calling this inferior red-coated telescope a "dark-light night vision telescope" or "infrared night vision telescope". In fact, the real infrared night vision device uses photomultiplier tube imaging, which is completely different from the principle of a telescope. It cannot be used during the day, is expensive, and requires a power supply to work.

Material: In order to reduce costs, most ordinary telescopes on the market use plastic bodies and tubes. Only a few high-end products and military models use all-metal structures, which are expensive, but their sturdiness and durability are unparalleled. Although the appearance of several Soviet-made all-metal military telescopes from decades ago in the author's collection is very old, each part is still flexible in operation and has excellent optical performance.

Purchasing Guide:

Some people may think that the larger the technical parameters, the better, but this is not the case. Magnification is inversely proportional to the width of the field of view, that is, the greater the magnification, the smaller the width of the field of view, which is not conducive to search. The larger the diameter of the objective lens and the amount of light entering, the stronger the resolution when the light is insufficient, but this will inevitably lead to an increase in the size of the telescope, which is not convenient for portability. Having said that, you may feel at a loss as to what to do, but as long as you can learn from each other's strengths and weaknesses, you can still buy a satisfactory telescope. Here I would like to give you some suggestions for your reference when purchasing telescopes:

First, if you want to travel to the sea or the beach, please don’t forget to buy a waterproof telescope (especially recommended) Debao offshore series 7×50mm waterproof telescope produced in the United States).

Second, if you want to go out for sightseeing, you can buy a small telescope with a zoom function.

Third, if you plan to go hunting in dangerous areas that can be viewed from a distance but cannot be explored up close, you should buy a high-power telescope.

Fourth, if If you are going hunting or traveling for a long time, it is best to buy a variable magnification telescope. Here is a description of how to use it. Because the variable magnification telescope can be gradually adjusted from low magnification to high magnification, you should use low magnification first. , use a large field of view to conduct a rough search, and then use high magnification and a small field of view to conduct a careful observation.