Reflective telescopes have many advantages, such as: no chromatic aberration, can record information from celestial bodies in a wide range of visible light, and is easier to manufacture than refracting telescopes. But because of its inherent shortcomings: For example, the larger the aperture, the smaller the field of view, and the objective lens needs to be coated regularly.
For the material of the reflector, it is only required that its expansion coefficient is small, the stress is small, and it is easy to grind. The surface of the polished mirror is usually coated with a layer of aluminum film, which has a good reflection law in the infrared and ultraviolet regions, and is suitable for studying the spectrum and luminosity of celestial bodies in a wide range of wavelengths. In addition, the mirror barrel of a reflecting telescope is generally shorter. Large reflecting telescopes are mainly used for astrophysics research work, especially for dimming celestial bodies, photometry and direct photography.
The performance of reflecting telescopes depends largely on the objective lens used. The commonly used spherical objective lens has the characteristics of easy processing, but if the focal ratio of the designed telescope is relatively small, there will be more serious optical spherical aberration; at this time, because the parallel rays cannot be accurately focused on one point, the object image will change Got fuzzy. Therefore, the objective lens of the large-aperture, strong optical power reflecting telescope usually adopts an aspherical design, and the most common aspherical objective is a parabolic objective. Due to the geometrical characteristics of the paraboloid, the rays parallel to the optical axis of the objective lens will be accurately concentrated on the focal point, which can greatly improve the image quality. But even telescopes with parabolic objectives still have off-axis aberrations.
[Disclaimer: The above content comes from the Internet, and does not represent the views of this site. I hope some of the content can help you. 】
We (Alice) are a manufacturer specializing in the production of optical signs, focusing on providing supporting services for the furniture industry, machinery industry, electronic and electrical industry and other industries, mainly producing zinc alloy, aluminum, stainless steel, copper, brass, pvc Wait for different labels.
Contact us E-mail: sales03@alicelogo.com