Refraction of astronomical telescope
There are two types of prism materials, BAK4 and BAK7. These two materials have different refraction degrees. The refraction degree of BAK4 is as high as 95%, which is expensive, while the refraction degree of BAK7 is only about 80%. Relatively speaking, the price is cheaper
Choose the focal length of the telescope reasonably
Choosing the focal length of the telescope depends on the celestial body you want to observe. If you want to observe nebulae and look for comets, you should choose a short focal length lens; if you want to observe the moon and planets, you should choose a telephoto telescope; if you want to observe double stars, convergent stars, variable stars, and star clusters, it is best to choose a medium focal length lens. The middle focal length lens can take care of both ends and is more popular. Usually, a short lens means that the ratio of focal length to the aperture is less than or equal to 6, and a long lens means that the ratio of focal length to the aperture is greater than 15, and it is called a middle focal length lens in between.
Astronomical telescope multiples
According to the long-term observation experience of astronomers, the maximum magnification should not be greater than 1.5 times the aperture of the objective lens (expressed in millimeters), and with a telescope with an aperture of 100 mm, it should not be greater than 125 times when the atmospheric conditions are moderately quiet. The best tranquility can be up to 190 times; when the aperture is 200 mm, it should not be greater than 170 times when the atmospheric tranquility is medium. At the best tranquility, it can reach 340 times; in fact, for astronomers observing bright celestial bodies, the maximum magnification can reach twice, even 2.5 times the aperture of the objective lens (expressed in millimeters). However, too large a magnification makes the image larger and darker, and at the same time, the atmospheric jitter also enlarges, making the image more blurred.
According to the individual’s financial ability, try to choose a telescope with a large aperture
For beginners, it is recommended to choose 60mm, 70mm, and 80mm refractor if the conditions are better:
First of all, it is convenient to carry, use and maintain, and it can be taken out for observation frequently (above 100mm is relatively heavy and difficult to carry; the number of observations depends on the number of observations rather than the diameter of the telescope);
Secondly, even in cities with severe light pollution, you can view bright celestial bodies such as sunspots, moons, Jupiter, and Saturn. In addition, the price is low. When you buy a larger and better telescope in the future, you can upgrade it as a guide mirror and make full use of it.
The material of the astronomical telescope
Astronomical telescope materials are on the market: plastic mirrors, lens barrels, metal mirrors, etc. As long as a few military or high-end astronomical telescopes use metal materials.
Astronomical telescope bracket
In addition to the configuration of the astronomical telescope itself, the astronomical telescope bracket is also very important. A good bracket determines that the telescope will not tremble or shake during observation. The brackets of the astronomical telescope include: tripod, floor bracket, theodolite, equatorial mount and other brackets. Sex speaks for itself