Analysis of the difference between red film and green film for astronomical telescopes

Owning a high-performance telescope is the wish of every travel enthusiast. At present, there are a wide variety of telescopes on the market, with varying quality, and there are few articles about telescope knowledge, which makes many people feel unable to start. Today, Avery Optoelectronics will introduce to everyone!

The function of lens coating is to reduce reflection, increase light transmittance, and improve observation brightness. The color of the coating has nothing to do with the quality. The lighter the coating, the smaller the reflection, the better. However, in recent years, various red and yellow film binoculars with strong reflections and brilliance have appeared in the market, which is very attractive to consumers. In fact, this poor quality coating The reflection loses a lot of light, making the color cooler and darker, and the clarity is reduced.

What's more, some people call this inferior red film telescope "dark light night vision" and "infrared night vision telescope" to deceive consumers. In fact, the real infrared night vision device is a photomultiplier tube imaging, and the principle of a telescope It is completely different, cannot be used during the day, is expensive and requires a power source to work.

The function of the lens coating is to reduce the reflection, increase the light transmittance, and improve the observation brightness. The color of the coating should be determined according to the optical material and design. The lighter the coating and the smaller the reflection, the better. Generally, the color of the astronomical telescope lens is interference The color of the magnesium fluoride film is determined by the thickness. The red film is slightly thicker and the green film is slightly thinner. From the visual perception, the red film has a colder tone and the green film has a warmer tone.

The coated film is an anti-reflection coating, that is, the light reflected from the front and rear surfaces interferes and weakens each other. Human eyes are most sensitive to green light, so green light should be anti-reflection, and the lens should be purple or red when looking at the glasses. The red film is the best because the light wavelength is different to the green light and the red-violet is increased.