Choosing the Right Color for Telescope Lens Coating: Tips and Precautions
Observant individuals may notice a light-colored coating on their telescope lenses, especially when viewed from an angle. These coatings can appear blue, green, or even red. Have you ever wondered what this layer of color does? The colored film on telescope lenses is also known as the spectacle lens film and serves a specific purpose.
- Purpose of Spectacle Lens Film: The primary function of the spectacle lens film is to improve the quality of the image observed through the lens. By applying a polarizing film to the surface of the objective lens, light transmittance is increased, and light reflection is reduced. This allows the observer to receive more light, making it easier to see the observed object clearly.
- Color Classification of Lens Films: There are two main types of lens films: single-layer and multi-layer.
- Single-Layer Film: This type of film is typically used in entry-level telescopes and is often blue. It provides antireflection for a medium wavelength of light.
- Multi-Layer Film: This film enhances light reflection across multiple wavelength bands, reducing color deviation and improving observation brightness. Green films are common multi-layer films, with green film telescopes being widely available on the market. There are also red films, known as infrared films, which are multi-layered but often fakes.
- Choosing the Best Film for Your Telescope: Is blue or green film better? Based on the classifications, green film lenses are superior to red film lenses. Red film, being monochromatic, can be monotonous and may cause eye fatigue after extended use. Green film, on the other hand, provides a more comfortable and relaxed viewing experience with a wider anti-reflection passband and a broader flat field of view.
- Recommendations for Beginners: For novices, a cheaper blue film telescope is a good starting point. Entry-level users can learn the basics of using telescopes without the need for high-quality lenses. Blue film telescopes are more affordable and cost-effective for beginners. As users become more experienced and have higher requirements, they can opt for green film lenses or more advanced options.
By understanding the purpose and types of telescope lens coatings, users can make informed decisions when choosing the right telescope for their needs.