Tips on buying telescopesApexeloptic
If you’re a novice photographer, you might have all sorts of doubts when it comes to buying your favorite pair of binoculars because you don’t know anything about telescopes. So with that in mind, the author has compiled this guide to give novice photographers a few tips on buying telescopes to help you get the telescope you want.
1. Common knowledge of telescope specifications
The size is mainly determined by the multiple and the aperture of the objective lens. The multiple of a telescope is how much it brings something far away closer together. In addition, the higher the multiple is not the better. If the multiple is too high, the object looks very shaky and not so clear, and it is not convenient for us to carry. The telescope’s physical environment is also important. The larger the aperture, the more comfortable we are looking at objects, but it is the same as the multiple, the larger the aperture, the larger the volume of the telescope, so we have to choose the telescope according to their own choices.
2. Common knowledge of selecting telescope optical components
The telescope market is mixed, and the development of telescope materials is changing with each new day. Before 2000, inferior telescope manufacturers used substandard optical components to replace them, and after 2001, resin lenses emerged as a rookie, with lower costs and further reduced optical performance. The prism of the optical element identification method, because of the large volume of telescope prism, is difficult to manufacture with resin, so it is a shoddy method.
It is also easy to identify, turn the telescope upside down, and look at it from the objective end to the bright and open place. If there is a broken black line or black stain in the inner part, it means that the telescope is assembled with waste. The broken black line and black spots are broken back and broken points of the prism. In the lens identification section, look carefully at the eyepiece of the telescope. If it is not pale blue but white (actually colorless), the eyepiece is not coated.
Why is there no coating? Because it is pressed with plastic resin, put in the coating machine before coating in the preheating stage of the coating material was baked in high-temperature deformation or melting. The eyepiece system of a telescope, however, consists of several lenses, some of which use the outermost lens with optical elements and the inner one with resin lenses.
So this kind of colophony lens has a shortcoming, it is like quality is bad, especially chromatic aberration and distortion are extremely serious, might as well take a telescope to look at the distant rod-shaped object, had better be a light color. For example, telephone poles, if the edge of the image is covered with a rainbow-like coat, and the telescope’s edge field of view is very blurred, it is a fake.
3. General knowledge of optical effects of telescopes
Generally, when we buy telescopes, we will see the same specifications of the telescope, the price is very different, which is mainly our telescope lens coating is different, because it affects the quality of the telescope optics. Military telescopes are usually the brightest, and the brighter they are, the farther they can see.
The better the coating, the more transparent and darker the lens. There is also a telescope is red film telescope, the lens of the red film can not only increase the brightness of the telescope but also make the image more like, you can also choose this type of telescope.
4. Common sense of telescope multiples
There are no technical difficulties with high-power telescopes. You can go as high as you want, but there are a lot of negative consequences. The first is brightness. The higher the multiple, the worse the surface brightness of the object will be, because the area of the object is magnified proportional to the quadratic magnification, and the brightness decrease will be very obvious.
Of course, if the telescope aperture is large, the multiple can be appropriately high, but the hand-held telescope aperture is generally not more than 50mm. Even more important is the jitter caused by high power. Handheld telescopes have slight jitter, but this slight jitter becomes very noticeable when magnified.
What is the use of enlarging the magnification of the telescope when the wobble of the image makes it impossible for the human eye to fully observe the details of the image? If the telescope can be fixed on the tripod, the magnification can be higher, of course.
However, for the ground-to-ground telescope, due to the limitations of brightness and resolution mentioned above, the magnification can not be too high, otherwise, the image will be very dim and fuzzy, and the field of view is too small, and it is difficult to find the target. In general, the highest magnification we see in large binoculars for ground observation is 60 times larger and has diameters of more than 100mm.
5. Buying common sense on telescope functions
The nitrogen inside the telescope has the effect of water and also prevents the internal lens from fogging and mildew, which is mainly because the telescope is well sealed, so this increases the durability of the telescope. There are generally Porro prism and roof prism. Porro prism, although large, has a simple structure, high light transmittance, and good imaging quality. Roof prism, though smaller in size, has a complex structure and low light transmittance.