This D90F900 glass objective lens is a high-performance DIY telescope accessory designed for refracting astronomical telescopes and optical parallel tubes. With a 93mm aperture and 900mm focal length, it gathers ample light for clear views of both deep-sky objects and planetary details. Its blackened separated structure reduces internal reflections, while the multi-layer broadband coating ensures high light transmittance and true-color imaging. Included spacers guarantee precise optical alignment, preventing light path deviation. Made of durable K9 optical glass, it withstands outdoor conditions, making it an ideal core component for astronomy enthusiasts building customized telescopes or optical devices.