望远镜的放大倍数faq（Magnification of the telescope FAQ）Telescope magnification FAQ (FAQ) -- for beginners
Originally wanted to write a telescope FAQ, becau first wrote the telescope multiples related topics, first stick out.
Without careful consideration, mistakes are unavoidable. Plea correct them.
First, what is the magnification of the telescope?
Is an object with the naked eye obrvation angle with telescope in the same place to obrve the same object angle magnification. For example, the angle of a bird is 6 cents per eye, and a telescope is 60 angles, and the telescope has a magnification of 10 times.
横的读音Two, how to calculate the magnification?
Magnification = objective lens focal length / eyepiece focal length.
If the telescope does not indicate the focal length of the object lens, it can be measured practically. For example, measure the diameter of the sun image, and calculate the diameter of the sun according to th
e imaging diameter of 8.7mm. In addition, the focal length of the objective lens can be estimated from the length of the lens barrel. For some special telescopes, the light path may be refracted by the internal prism or plane mirror, which will shorten the length of the actual lens barrel, and the ridge shape refraction is not easy
to obrve even outside. In addition, the telephoto lens has a special structure, although it has no reflection, it can also make the length of the tube far smaller than the focal length.
Three, whether amplification is bigger, the better?
No, it isn't。 The magnification of telescopes should be moderate, and the main limitations are as follows:
李明足球
1, amplification is too large, should not be stable
Binoculars are generally hand-held, more than 10 times or so, shaking badly, is not conducive to obrvation, eye fatigue, and even cau naua. Fixed ratio is too large will telescope becau the wind sways grass caud by vibration. For yourlf, 12 times the handheld limit, and the best elbow is supported by the obrvation, the body or telescope attached to some fixed object.
2, when the magnification is large, the actual field of view will decrea correspondingly
In general, the larger the multiplier, the smaller the area that can be obrved simultaneously. This is not only due to the eyepiece, even if the eyepiece can keep the viewing angle unchanged (e.g., 60 degrees) when the focal length changes, and the view field is inverly proportional to the magnification due to the decrea of the viewing area. In this way, it is not conducive to the discovery and arch of the target, especially the obrvation and obrvation of the frequently changing targets. Even if you get a good target, it's easy to lo your
target when it's slightly wobbly. For automatic tracking devices, manual adjustment is often required to keep the target within sight.
3, in the ca of the same objective aperture, the greater the magnification, the lower the inver square of brightness. For example, 50mm in diameter, 7 times the brightness (index) was 50, 10 times 25, 15 times, 25 times 11 is 4, and the brightness of the object decreas will directly affect the effect of the human eye (eye resolution, color brightness decreas with wor). Generally speaking, the daytime brightness is less than 5 and the nighttime brightness is less than 20, it is difficult to obrve faint objects. Large aperture telescopes have the advantage at this point, for example, when
the aperture 300mm mirror is magnified 50 times, the brightness is still 36 (very bright). In addition, the brightness of the solar system is obrved
High, basically not subject to this restriction.
4, the acquisition of large multiples usually through the short focal length of the eyepiece. The focus of the eyepiece is short, which will result in the small distance between the eye and the eye, the small angle of view, etc., resulting in the discomfort of obrvation and unfit for wearing glass.
5, the atmosphere itlf and other obrvation conditions are not ideal also limits the maximum magnification.
There is a good atmosphere of peace, can achieve the following 1 conds, though, the best 1 points for the human eye angle
resolution, magnification of more than 100 will be affected, such as watching the moon will generate steam rising jitter effect, low angle is more rious. If the atmospheric tranquility is good, you can choo a higher magnification.
6, multiple lection is too large, beyond the theoretical resolution limit, will cau invalid amplificatio
n
团圆酒Theoretically, there is a limit to the resolution of the telescope, 140/ millimeters,灵芝孢子粉有什么功效
The unit is angular conds (bad on the obrvation of Huang Lvguang, the most nsitive human eye). A good telescope can't exceed the limit, but it can only be clo. One of the functions of the telescope is to obrve the details. After the choice of multiples is too large, there will be no more details becau of this theoretical limit, so it will lo its meaning. However, the choice of magnification is not only related to the theoretical resolution of the telescope, but also to the obrvation conditions at that time, especially with the obrver's own eyesight. The choice multiple is the number of millimeter of objective aperture multiplied by 1.5 (also multiplied by 2), which is a reference value for ordinary conditions. Bad eyesight, good quality can have multiple telescope choice; on the contrary, the eyesight is very good (or do not want to e when the obrvation is not ideal imaging too much), you can put the general quality of the telescope, multiple choice low point. For example, the aperture 80mm refractive mirror, the maximum can choo 120 times to 160 times.1月1日
Four, caliber 50mm binoculars, how to choo multiples to buy it?
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50mm binoculars is a very good size in price, performance, portability and so on. It's worth choosing
for beginners.
If the main handheld, multiples should choo about 10 times.
I ud to have 16 times, holding unstable, so it has been nt to people;
If you can put on the three tripod, and the obrvation target is mainly solar system objects (such as the moon, Jupiter, etc.), multiples can choo a larger point, such as 16-20, but must be careful.
神潭大峡谷In terms of faint objects as the obrvation object at the same time the night obrvation, optional low multiples, such as 7-8 times.
If you have multiple us, you can choo 10 times, that is, 10x50 is the most versatile: the pupil is 5, the brightness is good, the hand is just right (I usually u 7x35 and 12x60 two, the exit pupil is 5mm)
Five, binoculars can choo to zoom?
男宝宝的名字You can choo, but you'd better not change it too much.
The zoom telescope is very convenient and suitable for many purpos. It is at the cost of sacrificing the following indicators:
