Friends who observe carefully may find that there is a faint color on the lens of their telescope, especially when viewed from an angle. Some are blue, some are green. Did you think of the effect of this layer of color?
The function of the lens film
The physical principle is to destroy the scene you observe from the lens under direct light, resulting in unreal imaging. In order to enhance the authenticity of vision, a layer of polarizing film will be coated on the surface of the eyepiece and objective lens. Increase the light transmittance and reduce the reflection of the eye lens to the light so that the observer can receive more light to facilitate observation.
Color classification of glasses film
There are two types of single-layer film and multi-layer film. The single-layer film can only be used in simple entry-level telescopes for the antireflection of light of one mid-wavelength, and the blue film telescope is more common. The multi-layer film can enhance the reflection of light of many bands, can well eliminate the color deviation of the magnification of the scene, and improve the brightness of the observation. The green film is a common multilayer film, and the more formal one on the market is the green film telescope. Of course, there are red ones called infrared films which are also multilayer films, but most of them on the market are fakes.
What kind of film is good for telescopes?
Whether the blue film is good or the green film is good is what we care about. From the above classification introduction, it can be seen that the green film lens is better than the red film. The red film as a monochromatic film will appear very dull and boring, and it is easy to feel discomfort and cause eye fatigue after observation. The green film is technically more difficult to achieve than the red film. The green film will make the scene you see more comfortable and easy, and the anti-reflection band will be wider and the flat field of view will be wider.
Novice friends can still choose the cheap blue film telescope when buying because the entry-level friends just learn more about the use of telescope knowledge and skills through it. The quality requirements of the mirror are not so high, and it is more affordable and cost-effective. First, try to get good quality. Friends who have higher requirements for telescopes can choose green film lenses or even more advanced lenses.