1. The distance of a telescope is related to a person's vision:

For example, the letters on the eye chart: when tested at a distance of 5 meters, people with good vision can see the bottom line, while people with myopia may only see the first few lines. If the eye chart is placed at a distance of 50 meters, using a 10x telescope is equivalent to zooming in 10 times (the same as 5 meters).

2. The distance of a telescope is related to the size of the object:

There is an ant at 1000 meters. If you use a 10x telescope, it is equivalent to zooming the ant in to 100 meters. You will definitely still not see it. Can you say that this telescope cannot see 1000 meters? If there is a person at 1000 meters, you use a 10x telescope, which is equivalent to zooming the person in to 100 meters. You will definitely see it clearly.

For example, using the same telescope, the same person observes a billboard at 1000 meters. After rain, in sunny weather, you can clearly see the small words on the billboard. But on cloudy days without the sun, when there is car exhaust and dust in the air, you may not be able to see clearly. Furthermore, if there is fog, that is, there are a lot of suspended particles in the air, visibility is reduced, and you may not be able to see even 5 meters. This is why highways are blocked in foggy weather.

3. The distance of a telescope is related to the quality of the telescope itself.

For example, if there is a person 1,000 meters away, the clarity of the telescope seen by a 10x telescope and an ordinary 10x telescope that costs dozens of yuan is very different.

Two telescopes with the same parameters (magnification, aperture, field of view, exit pupil distance, exit pupil diameter), the price of telescopes with exactly the same size and appearance may differ by several times or even more, which is not surprising.

4. The price of a telescope has little to do with the magnification:

Military telescopes are almost never more than 10 times. The lens, prism, coating, and structural parts of the telescope determine the quality of the telescope. The transmittance of a good telescope can reach more than 90%, while that of a poor telescope is only 50%-60%, and the sky is obviously dark when the poor telescope is used.

Seeing this, you should understand why there is no data on the distance of the telescope? As long as there is an infinitely large object, the telescope can see infinity. We can see planets hundreds of light years away without a telescope, and we can also see them with a telescope. The moon is very far away from us (380,000 kilometers), but we can also see it with a telescope. But molecules, atoms, etc., no matter how good the telescope is or how close the distance is, you can't see them. Why? Because they are too small!

5. Misunderstandings about the magnification of telescopes

There are many things more important than magnification when choosing a telescope, such as exit pupil diameter and field of view. The magnification cannot be the only criterion. Because if the magnification exceeds the standard allowed by the telescope specifications, the clarity will decrease. For example, for a telescope with an objective lens diameter of 50 mm, the magnification should generally not exceed 50 times. In fact, a telescope of about 10 times is enough to meet most of our usage requirements.

Due to the public's lack of understanding of telescope expertise, they often blindly worship higher telescope magnifications, so some inferior products deliberately mark the magnification as hundreds or even thousands of times to mislead consumers. In fact, the indicator for measuring the power of a telescope is the aperture. For example, when mentioning the world's famous astronomical telescopes, people often say how many meters the aperture is, not how many times. Because our eyes cannot see things that are smaller than the retinal optic nerve cells, according to calculations, the visual resolution of the human eye is 60〃. Under a certain objective lens aperture, it is meaningless to increase the visual magnification infinitely without seeing more details. According to the Rayleigh criterion: the resolution of the telescope is proportional to the aperture of the light, from which it is deduced that if the aperture of the telescope is 60 cm, the normal magnification should be 23 times. If the magnification is higher than the normal magnification, it will not improve the resolution. Through comprehensive consideration, the magnification of the telescope can be equal to the aperture of the light (cm). Experienced people know that it is difficult to observe telescopes with a magnification of more than 20 times without support, because you can even feel the shaking caused by your own heartbeat being magnified. The actual magnification of those inferior telescopes is generally no more than six times. At present, the popular magnification of telescopes equipped by the military of various countries in the world is seven times.

Simply put, the visual magnification of a telescope is equal to the ratio of the focal length of the objective lens to the focal length of the eyepiece. However, it should be pointed out that our eyes cannot see clearly objects whose images are smaller than the optic nerve cells, and the visual resolution of the human eye is 60". Under certain objective lens aperture conditions, the diffraction resolution of the telescope is certain. Simply increasing the visual magnification will not see more details, but will only reduce the subjective brightness, so it is meaningless. In fact, the various parameters of the telescope are not isolated, but constrained by each other. You can't have your cake and eat it too.